Model Engine Maker

Engines => From Plans => Topic started by: gary.a.ayres on February 10, 2019, 11:34:07 PM

Title: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 10, 2019, 11:34:07 PM
This is my first ever attempt at building an engine, so I decided to keep it as simple as possible and start with a half inch (12mm) single acting oscillator. Given the levels of knowledge and skill that many of you have I suspect you may find such a basic build less than exciting, though I am adding a couple of touches of my own to the project which may take it a little bit away from the ordinary.

Fundamentally the engine will be a version of the single-acting oscillator designed by Steve of Steve's Workshop http://steves-workshop.co.uk/steammodels/simpleoscil/simpleoscil.htm (http://steves-workshop.co.uk/steammodels/simpleoscil/simpleoscil.htm), where plans and guidance are posted. My main reason for choosing this version out of the many similar engines that are out there is that like most of my tooling, it's metric. My version differs from Steve's original in a few non-critical dimensions due to the materials I have available. I have also opted for a particular look of my own devising which has nothing whatsoever to do with functionality. Call it steam meets dieselpunk meets Flash Gordon...

I marked out the frame on 12mm aluminium plate and the pulley on a slice of brass bar, making sure that the frame was bigger in all dimensions than the rectangular frame of the original:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824191.jpg)

I can hear you gasp at what is to all appearances a very scrappy bit of marking out. However, there was method in my madness. CNC would be perfect here (one day...) but I used the same approach that I have used to create irregular but clean-edged forms in abstract paintings such as 'Trident', below, where I would sketch roughly on the canvas in pencil first, then gradually refine the lines with paint until I got the forms I wanted:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824193.jpg)

 I did the same with the engine frame,  but instead of refining the form with acrylic paint and brushes, I tried a variety of tools and methods before settling on a combination of chain drilling and small drum sanders of various sizes held in the mill chuck. I'd rather have used my drill press for this but the vibration shook the MT3 shank  of the chuck out of the spindle (why don't drill presses have drawbars as standard...?).

If the flywheel looks oversized relative to the frame it's because it is. It needs to be turned down to size.

The bottom of the frame needed to be trued up then drilled and tapped to to make two threaded mounting holes to attach it to the base. I attached it upside down to an angle plate using two toolmaker's clamps, then checked the level of the scribed line with a height gauge before squaring the piece with an endmill and drilling and tapping it M5:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824189.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824190.jpg)

A recess was then milled in the flywheel using my small rotary table with its four-jaw self-centring chuck:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824188.jpg)

And that's as far as I have got so far. Pictures below. A reasonable start I suppose:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824192.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824187.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824186.jpg)

 :)



Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on February 10, 2019, 11:43:11 PM
Good choice on a first engine, its where most of us started out, you will learn from it and move up quickly, jusdging by your other work!
 :popcorn: :popcorn:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on February 10, 2019, 11:46:25 PM
Looking good Gary, it's nice to see a new approach to standard design  :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Johnmcc69 on February 10, 2019, 11:52:39 PM
 :ThumbsUp:
Excellent start Gary! Parts looking good!

 John
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: AOG on February 10, 2019, 11:57:21 PM
Itís looking good but I do have a general suggestion based on my own painful experience. When you are going to do a shaped part like that do the shaping last. Start by squaring up a rectangular blank. The straight edges make it very easy to align and hold the part while you put in the interior holes and features. When those are in then shape the outside. It isnít going to be much of a problem with the part you are making now but trust me, the lack of good square references can bite you.

Tony
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 11, 2019, 12:04:27 AM
Many thanks gentlemen.

@ Tony - yes, that makes sense. Next time...!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on February 11, 2019, 12:58:04 AM
Always enjoy watching first engines Gary. I am excited along with you and will definitely be following along.

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: 10KPete on February 11, 2019, 03:04:52 AM
 :popcorn: :popcorn:

Pete
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 11, 2019, 09:30:43 AM
Many thanks guys - very kind of you.

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Ramon on February 11, 2019, 10:05:10 AM
Congratulations on making that start on your first engine Gary :ThumbsUp: I remember it well. Believe me when you see it run for the first time you will have a grin from ear to ear :D

I would reiterate the sound advice offered by Tony - get the parameters right before letting those obvious creative juices you possess take hold - work the outside to the details and not the other way round  ;)

Good luck with the rest of your build - your perseverance with your boiler will hold you in good stead :ThumbsUp:

Tug
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 11, 2019, 10:21:29 AM
Thanks for this Ramon - much appreciated.

Now that it has been pointed out to me it's very clear that it's better to keep things square for as long as possible and leave the fancy stuff to the end. I reckon I'll get away with it this time, as Tony says, but I can see how it could be a big problem with more complex parts.

I was partly driven by enthusiasm for my idea but also partly by uncertainty about how easy it would or wouldn't be to make curves of this kind in aluminium plate given the limits on the equipment I have. I didn't want to drill all the ports and so on, only to then spoil the piece when trying to shape it. Now that I have found a way of making these curves it should be easier to leave it until the end in future builds.

Cheers,

gary

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 11, 2019, 10:31:08 AM
Believe me when you see it run for the first time you will have a grin from ear to ear :D

Tug

PS - yes - I can't wait for that moment!   :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 11, 2019, 11:46:43 PM
Another session today. First, a recess was milled on the flip side of the flywheel to match the first one:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824260.jpg)

Most of the subsequent work on the flywheel will be done on the lathe. To try to avoid a wobble, I intend to turn it in one setting, between centres on an arbour made of the same stock as the main axle.

The base was then marked out on a piece of the same aluminium plate as was used for the frame. It was also marked out in a similar style. Gives new meaning to the term 'scratch built'. Or maybe that's where the term came from in the first place:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824259.jpg)

I swear I'm starting to like the smell of that stuff just a bit too much...

This time, as I had only external curves to deal with, I used a coarse grit on the belt sanding attachment of my Coronet Major woodturning lathe to shape the piece, followed by a medium grit flap wheel in the drill press. As it happened I did not work to the scribed lines because a pleasing shape began to emerge before I reached them, so I just flipped the part over, gave it a few more passes on the sander and called it done, minus the finishing. I used M5 transfer screws to transfer the hole positions from the bottom of the frame to the base:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824263.jpg)

The position of the frame on the base was judged by eye, but the distance between the holes needed to be retained, hence the transfer screws. First time I've ever used them, but it will not be the last   :ThumbsUp:

Once the clearance holes were drilled, they were counterbored on the underside of the base to accommodate the heads of the M5 cap head screws:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824264.jpg)

Looks a bit spooky here, but less so since I cleaned off the layout fluid...

Finally, the frame was screwed to the base:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824262.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824265.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824261.jpg)



Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on February 11, 2019, 11:56:11 PM
Great progress!


 :popcorn:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on February 11, 2019, 11:56:20 PM
Very nice looking shape to it Gary. I noticed on the second picture in this post it looks like a 3D effect. No doubt just the combination of colors and patterns but I did do a double take. Was looking on my phone though. Anyone else getting the same effect....kind of cool.

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 12, 2019, 12:03:09 AM
Many thanks guys.

Your interest and support are greatly appreciated.

 :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 12, 2019, 12:05:32 AM
I noticed on the second picture in this post it looks like a 3D effect. No doubt just the combination of colors and patterns but I did do a double take.
Bill

Yes, now that you mention it it does look like the blue floats above the background. All I did was up the contrast and brightness slightly and sharpened it up a little (like I do with most photos).

The blue really pops!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: cnr6400 on February 12, 2019, 02:31:11 AM
Great progress Gary, well done!  :ThumbsUp: :popcorn:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Ramon on February 12, 2019, 07:08:41 AM
Hi Gary, your engine will certainly have some character  :ThumbsUp:

A thought, as I can't see you've mentioned it - your standard is aluminium - I assume you will be making the cylinder from brass? If so, I would bond a brass wear plate to the standard where the cylinder pivots against as aluminium will quickly wear and possibly score quickly spoiling the seal. Were you thinking of it, a cylinder made from aluminium will gall and pick up even more so. Brass to brass is fine - aluminium to aluminium is not.

Standard epoxy with a couple of small pins would be fine.

Hope you don't mind the comment - Tug
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 12, 2019, 09:45:50 AM
Thank you both.

@Ramon - my plan is to use brass for the cylinder. In the Steve's Workshop plans he uses brass for the standard and the cylinder. I decided to use aluminium because I had some available but also because I fancied the look. I have in fact been wondering how the ali would stand up to wear, and the idea of some form of protection had occurred to me but only in a vague and unformulated sort of way and I had no clear thought about what to do about it. So thank you for your suggestion, which I will follow.   :ThumbsUp:

Similarly, in the plans the brass standard is bushed with bronze for the main axle, but the narrower cylinder pivot just goes straight through a hole in the brass. I'm now wondering if - given I'm using aluminium - whether the hole for the cylinder pivot should also be bushed?

Cheers,

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on February 12, 2019, 10:21:56 AM
Taking shape nicely, not sure how well a piston will run in a matching curved cylinder though  ;)

As for the bushing, as you are taking the time to make a more elaborate 'delux' oscillator it makes sense to spend another 10 mins making one even if it isn't essential.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 12, 2019, 10:57:47 AM
No problem Peter. Banana-shaped piston.

On the bushing - I agree   :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Ramon on February 12, 2019, 11:24:39 AM
Hi Gary, yes I would agree with Peter it would be well worth putting a bush in. The humble oscillator may have a simplicity about it but it still has it's issues that can easily be improved upon.
The main one is usually the lack of true squareness of the pivot to the cylinder block and the subsequent misalignment and wear that rapidly results as a consequence.

One way to overcome that problem is to make the pivot a composite one - a short stud in the cylinder with the pivot pin itself tapped a slightly loose fit which will then pull up to the  face square in both directions. The other benefit gained from this is that the pin is not pivoting on a threaded surface but a smooth one which can be made much larger in diameter for a much better wearing surface - within the constraints of any internal passage ways of course.

The pin can be made as a simple tube tapped right through and faced square on the end with a further stud to lock it or can be made as one piece as in the image (Note 'stud' here need only be a piece of threaded rod)

This should give you the idea
(https://lh3.googleusercontent.com/Wz4HpgCMR5iG38aknF9QyAXCfDV1xzfDKKrUgmTYRHvkbOxjNzTV-syhWqg15ic5A8ECcfFR0Oj0OPFRKPTc3d5gq9yrPDNC7PZrIjGmu1IjgtzWc00zeW-PS7Eed7MUVTAPDyJ0YL_M81d5SVKrUfC90SUB9WrGfn8qm05mloqLsmiIBMY1KcmEDrdaVhaTGuKM8l7LHPU-igj6FwKsquCjG9v7gX7ZXv95Nb3tyRJV8ox5UPUfjUTLjFYE5Upq3zSP2MdIMmOsKZQLu6uCngoScqjNBxUqz_G-5OFf8X5X_VwCDGftHujFgCHsFVtdS_SQ_ra4xwOZwj2ogiYMdCrUBWAfYVl0x6Tg4GKCaZV8zu3o638WlGjEjBYWuJs72cQO4ip0vLkjLvqcpS9OHN7GGWi5NwA1-D6kBbmQGs_gp4tqz-vOYF8ZLQsVFDqWhsoRSE1yJPXyrZwS7m4ks1Y04flde6nGpaRJvpupPe9pE7aBiDUotkwOBN3SAT8q-N7RRxGCEMevpUVrFkb_tOLfei-XAb39ZmvO3R2fP_G5oJMV--fj_ONXJAZmS21X-aeVXTWLfiOScZoecvOhc6VGpyVq1cpfYfMS8rqQiClLu-cAVRcrSieJU8X3bpSZ9HXZd4lzqzFH9t9GIq_eXELlN5_g_GU=w1218-h913-no)

Hope that's of use - Tug
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on February 12, 2019, 11:43:13 AM
Tug, the idea of a composite pivot makes a lot of sense and is a simple solution  :)

I watched a video by mrpete222 on youtube recently, the way he ensures squareness of the pivot is to drill right through the cylinder so that if there is any out of squareness on assembly he passes a rod right through the cylinder then machines the port face square in the lathe. Once all is ok he plugs the extra hole.  I can see the idea working but it seems to me like an awful lot of messing about.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Zephyrin on February 12, 2019, 11:47:04 AM
Hi Gary,
don't forget that large chunks of metal to heat make starting difficult for a little steam engine...
I agree with the upper statement on aluminium and brass together, and with a bronze bushing.

the cylinder pivot hole has to be absolutely perpendicular as should be the cylinder face with its axle for a good runner.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Jasonb on February 12, 2019, 01:12:16 PM
Off to a good start Garry. We had best not tell you about the RMC engines as you will get even more carried away with the unusual shapes :-X

J
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 12, 2019, 01:28:59 PM
Thank you all  :)

@Tug - yes, the composite pivot idea makes a lot of sense in terms of solidity and a snug perpendicular fit. I'll most probably go with it.  :ThumbsUp:

@ Peter - agreed - mrpete222 is a treasure but when I first saw his practice of drilling right through the cylinder then plugging the outer hole (in one of his earlier oscillator builds) I thought 'hmm... I don't fancy that much...'.

@ Zephyrin - I'll try to get it as perpendicular as possible. Also, I have just ordered a bunch of nice metric reamers to make proper holes with in this and in future projects (heck, it's not cheap, this game...). On having a lot of metal to heat - I'll be honest - I never thought of it. I do plan to make some decorative holes in the standard once everything else is done and I can see what room I have left and according to the look (you can see some roughly sketched in on the first picture at the start of this thread). The flywheel will also have a circle of holes drilled through the recessed part. I don't know if these will make any difference but in the worst case scenario I could always radically revise the whole standard. Hopefully it won't come to that, though I have picked up that you know quite a bit about the thermodynamics of such things   :)

@Jason - RMC engines, eh? Aha... Google is my friend!   ;)

Cheers,

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 12, 2019, 01:35:43 PM
We had best not tell you about the RMC engines as you will get even more carried away with the unusual shapes :-X

J

Just took a look, and I like! Ideal for a browse later when I have more time.

If I ever get any good at this, and when my little furnace is operational.... *daydreams about exotic engines of the future...*   8)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on February 12, 2019, 06:43:45 PM
Just a thought Gary but if you are interested in making engines with an artistic flair have you considered buying a set of French curves?

They cost next to nothing but could prove useful in marking out curved profiles etc.

https://www.ebay.co.uk/itm/French-Curves-Technical-Draughtsman-Drawing-Stencil-Set-of-3-Ruler-Template/191907678398?epid=1675145184&hash=item2cae96c8be:m:mXWeUGxp5qpxareDktwawpA:rk:7:pf:0

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 12, 2019, 07:17:22 PM
Peter -

that's a really good idea. I don't foresee any more curves on this one, but may well procure a set for the next one.

 :ThumbsUp:

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 12, 2019, 11:41:08 PM
This evening I started working on the cylinder and the main axle.

The plans call for a piece of 25 mm round brass bar as the starting point for the cylinder. I found one small piece among some offcuts on my shelf. It was only a little longer than the required 30 mm and by the time I had faced it at both ends (which entailed a silly mistake that I should not have made) it was 29.65 mm long. I know that 0.35 mm is actually quite a lot, but I assume that in a single acting oscillator the length of the cylinder isn't critical to that degree. The alternative would be to order some more brass bar online (as these materials are hard to get hold of where I live) and that would seem to be overkill for 0.35 mm off the length of an oscillator cylinder. However, please correct me if I'm wrong.

The main axle is 6.0 mm in diameter in the plans. The nearest I had was round bar of 6.25 mm diameter in what I think is silver steel (it came as part of a whole bunch of stock with a Myford lathe that I bought from a man who had built a loco). I turned a length of it down with very light cuts and polished it with emery paper. It's now sitting at about 6.10 mm and I think it will need some further polishing but I'll leave this until my new reamers arrive and make a 6 mm reamed hole to test the axle with so I can hopefully bring it to a nice running fit. The length is arbitrary at this point - I deliberately left it on the long side because I might put a pulley on it at the end of the build, and in any case better too long than too short at this point.

Pictures:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824372.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824373.jpg)

I'm unlikely to be doing anything to the engine now for about a week as I have to work for the next two days and am then visiting my daughter for a long weekend...

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on February 13, 2019, 12:30:32 AM
You can likely adjust the thickness of the piston to compensate for the slightly short cylinder. Shouldn't be a big issue.

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 13, 2019, 06:09:16 AM
Bill - that had occurred to me. I can look at that if needs be.

Thank you.

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: MJM460 on February 13, 2019, 07:03:32 AM
Hi Gary, itís coming on well and will look interesting when you have it finished.  (Unlike my square blocks.)

While 0.35 mm is a long way out for a 3 mm bolt hole, let alone the shaft bearing diameter, it may not matter at all, or even improve things when in the cylinder length.

Draw a little sketch with the crank at top dead centre.  Calculate the distance through the frame from the crank shaft cylinder pivot pin and inside of the cylinder top head.  Then calculate from the shaft through the crank pin at top dead center, piston rod and piston.  Then you can do the subtraction to see how much clearance there is above the top of the piston.  If it iis supposed to be around millimetre, a reduction by 0.35 will not matter.  The main thing is to keep an eye on that clearance at top dead centre and not allow it to disappear as other components are made with their inevitable tolerances which inevitably add up the wrong way.  That is what Murphyís law is all about.

The piston sides are the bearings through which the piston causes the cylinder to oscillate, and longer is better, so long as the bottom of the piston stays within the cylinder.  So if you do run out of clearance at TDC, I would suggest making the piston rod a little shorter rather than shorten the piston.  Though you also have to check that the crank web/disk clears the bottom of the piston (and cylinder) as it goes through TDC.

That is why an oscillator is such a great place to start, even with such a simple engine, there is so much to learn as you build it up.  With more parts in a more complex engine, there are more places where the dimensions of one part affect the clearances for another.  Part of the preparation before you start on a more complex model, is to identify these critical dimensions.

Like your boiler project, you are learning so much from each step.  Well done.

MJM460



Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 13, 2019, 10:12:40 PM
Thanks for your kind words MJM460.

I take your point about shortening the rod rather than the piston. I didn't get it at first until I realised what you said, i.e. the piston causes the cylinder to oscillate (or at least is the final link in the system that does so), and the force for the lateral movement is transmitted through the sides of the piston. It seems to me that for this reason piston length could be more important in an oscillator than in a fixed cylinder engine...?

Not sure how much difference that 0.35 mm will make in my case, but I will carry out the calculation you suggest because I plan to have a go at machining the piston assembly as one, so it won't be possible to shorten just the rod after it's made. It would be different if the piston head and the rod were two components.

I think your engines and plants look great, btw.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: MJM460 on February 14, 2019, 03:52:37 AM
Hi Gary, yes you have got it on the piston length.  The calculation will tell you if you need to make any adjustments to the position of the crank pin bearing location before you finish off that end of the rod.

And yes, if the design has a rod packing and cross head, both of which keep it pretty square, the piston does not have to be so long.  Just enough for rings, or grooves or what ever you are doing to reduce leakage past the piston.  But at the same time, those same components have to be lined up very well or will result in extra friction, which is an extra complication for a beginner.  You already know more about what you will need to do, just from the experience of building that oscillating engine, things that are not always so obvious from a first look at a design.  Drilling a hole is easy, getting it in the right place is more difficult, and if you really need a precise location or alignment, another level again.

Thanks for your comments about my engines.  I think I was a bit harsh on myself, after all Elmerís engines are mostly square, along with so many other designs, and they all look pretty good.  I was just saying that I donít have the artistic flare that you clearly demonstrate in your projects.

MJM460

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 14, 2019, 06:22:01 AM
Yes - I'm with you regarding the piston. The calculation will tell me by how much the crank pin bearing needs to move by, as you say. That's the right way round to look at it. Even if the difference in this case proves to be insignificant in practice, it will be good experience for me to do the sums anyway.

Agree re Elmer's engines - there was a real aesthetic sensibility going on there, alongside the creative engineering. A lot of them are quite rectilinear in style but graceful nonetheless in a modernist kind of way. His #36 reversing wobbler is a good example of that I think.

Thanks again for your interest.

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 15, 2019, 01:07:29 PM
Just a thought Gary but if you are interested in making engines with an artistic flair have you considered buying a set of French curves?

That was a good suggestion Peter, and in response I have ordered these:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824546.jpg)

I won't need the actual French curves until I start another project of this kind, but the small circle templates will come in very handy for laying out the decorative holes that I plan to make in the standard of this one when it's done.

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 15, 2019, 01:11:28 PM
You can likely adjust the thickness of the piston to compensate for the slightly short cylinder. Shouldn't be a big issue.

Bill

Bill - I'm sure that's right, but having thought a bit more, given I'm a newbie at this and working from the plans, I decided not to take any risks with getting the ports to line up as exactly as possible. Probably being over-fussy but no harm. I also remembered that to get more bar I wouldn't need to order online, as a local small engineering firm owned by one Adrian have a scrap bin which is a veritable treasure trove. I found a piece of 25 mm brass bar at 37 mm long, which he kindly gave me for nothing. Perfect!

I'll turn it down to 30 mm and carry on with the build next week when I come back from my daughter's.   :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on February 15, 2019, 01:21:52 PM
Gary, where did you order the curve stencils, I thought about buying some but the ones I've seen don't come with the regular shapes like circles, triangles etc.

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Jasonb on February 15, 2019, 01:29:08 PM
The curves look to be knock offs of Rotring ones and some orange copies of Linex templates for the others.

Regarding the cylinder with such a small difference in length you could just leave the end cap a little thinner and have the piston travel  closer to the open end, provided you set out the ports from the pivot point it won't make any difference and you can put the extra brass away for the next engine.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 15, 2019, 03:06:04 PM
@ Peter:    https://www.amazon.co.uk/gp/product/B079L1XGKH/ref=ppx_yo_dt_b_asin_title_o01__o00_s00?ie=UTF8&psc=1 (https://www.amazon.co.uk/gp/product/B079L1XGKH/ref=ppx_yo_dt_b_asin_title_o01__o00_s00?ie=UTF8&psc=1)

@ Jason: I have no doubt you are correct. However, I've already started on the new bit of brass (quick fix of shop for 20 minutes before I  head off) and in any case it will be good practice for me to work to a plan as exactly as I can (apart from the frame and base of course!) for my first build. I guess a better understanding of the various tolerances will come in time. I'll keep the first bit of brass for the next engine, so nothing wasted.   :)

Cheers both   :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: JC54 on February 15, 2019, 07:49:21 PM
Hello Gary, this is the first engine that I made, mainly because it had no silver soldering. I just measured my cylinder and it is 29.85mm the piston protrudes 1.84mm when at BDC. It runs really well and will tick over at 2psi. One thing that I did find was that I lapped the cylinder and piston and then drilled holes for the endcap bolt threads. These made a slight "bulge" into the cylinder so I had to lap again. Next time I will drill and tap holes before final reaming/lapping.
     As several people have said it will take days to get that silly grin off your face when it first runs. I am now on my second engine a very simple beam engine. Best of luck John :old: :DrinkPint: :DrinkPint:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 16, 2019, 01:05:18 AM
Hi John -

thanks for the encouragement and advice.

I'd never have considered that the screws for the end cap could cause a bulge. Well worth being aware of.

Best of luck with the beam engine   :ThumbsUp:

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 17, 2019, 06:56:06 PM
So here we are with a little off-topic meander...

My daughter lives in Hove, East Sussex, on the South coast of England. We spent a very nice weekend hanging out together - we're like pals really. In Hove there is a Victorian pumping station which was converted to a steam museum some years ago - The British Engineerium. There are two engine houses, each containing a lovely original beam engine, I believe. Unfortunately it closed several years ago and has been standing intact but unused - and up for sale - ever since.

I was aware that it was closed but decided to make a pilgrimage there anyway, just to stand outside the inevitable locked gate:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824798.jpg)

This is what I would like to have seen:

http://www.youtube.com/watch?v=vKJg-15q0M0

What a waste. I wish someone would buy it and reopen it. Me - I can't afford it. How about you guys?  ;)

I did, however, decide that I could just about afford this nice old hand vice which I found in a huge second-hand emporium in the neighbouring city of Brighton (one of the coolest cities anywhere, never mind the UK). Ten quid. Not bad, I reckon:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/824796.jpg)

Back to the engine soon...

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on February 17, 2019, 07:30:05 PM
I've never heard of Hove pumping station but one that I'd really like to visit in the south of England is Crossness.

Just look at the pride the Victorians took in building magnificent cathedral of engineering - it's like some elaborate masonic hall.

2PGvO62zhss
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Jasonb on February 17, 2019, 07:34:10 PM
I went to the Engineerium years ago, they had a good collection of model engines on display all unique one offs of a good vintage.

I think I read that the guy who had bought it and started work and been jailed so it is up on the market again.

I have this photo of the engine down in the workshop stored away in my "future projects" file.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on February 17, 2019, 07:36:04 PM
Jason, as a matter of interest have you been to Crossness? It's in your neck of the woods isn't it?
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 17, 2019, 07:43:07 PM
I've never heard of Hove pumping station but one that I'd really like to visit in the south of England is Crossness.

Yeah - I have just been watching a video about it.

I'd like to see them all but this one really appeals:

http://www.youtube.com/watch?v=KhlJp1VZMB8

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 17, 2019, 07:45:28 PM

I think I read that the guy who had bought it and started work and been jailed so it is up on the market again.

I have this photo of the engine down in the workshop stored away in my "future projects" file.

Yes I believe so, Jason. A worker was killed in an accident and I believe the owner was found culpable, presumably through inadequate safety measures. It has been closed for quite a time I understand.

Looks like a great future project  :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 17, 2019, 08:02:03 PM
And then there's Kew Bridge Steam Museum in London, where they have the big pumping beam engine plus a collection of other engines too. I was there a few years ago and definitely plan to go again:

http://www.youtube.com/watch?v=YGoQQCM4SMU
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 18, 2019, 10:30:51 PM
...one that I'd really like to visit in the south of England is Crossness.

Just look at the pride the Victorians took in building magnificent cathedral of engineering - it's like some elaborate masonic hall.

Wow, yes Peter -

I just re-watched the video but this time at a more relaxed pace. Absolutely stunning. Seems to me that Crossness and Kempton Park are two awe-inspiring examples, each in its own way, both from very different stages of the steam era.

And both not far from London - one East and one West.

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on February 19, 2019, 12:19:38 AM
And then there's Kew Bridge Steam Museum in London, where they have the big pumping beam engine plus a collection of other engines too. I was there a few years ago and definitely plan to go again:

...
What an amazing machine!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 19, 2019, 08:55:51 PM
Yes indeed Chris. When I was there a few years ago, some of the other engines in their collection were running but this one wasn't. It was still magnificent though - the atmosphere in the engine house was like that of a temple, with its lofty fluted columns and strange sense of stillness. I felt this, and others have said similar.

Next time I go there, though, I'll make sure it's on a day when it's running.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 21, 2019, 11:27:43 PM
Meanwhile, back to an engine which is slightly smaller and a tiny bit less sophisticated than the above.

Slow progress.

The photo below shows the new cylinder blank, which is now the correct length of 30mm. Also, my metric reamers arrived and I have drilled and reamed the flywheel to 6mm, and have faced the rim and hub of one side of it..

So far so good. However, I have struggled with the main axle. The plans ask for a length of 6mm diameter silver steel. I didn't have any, so decided to turn down some thicker stock. It's not the money, as silver steel is cheap as chips in small quantities - I just thought 'use what you have'. The attempt shown in a previous post turned out to be tapered, so I abandoned it and adjusted my lathe tailstock. Since then I have been wasting metal, creeping up on the required diameter... and then past it to create a too-narrow axle and a slightly rattly fit for the flywheel. The last effort was the best, but I still wasn't happy with it and have rejected it.

This reveals my inexperience. It has been a frustrating couple of evenings. I then found some steel which is about 5.85mm diameter, which I had overlooked. The flywheel slides along it nicely, but still rocks a bit from side to side if encouraged to do so. The bearing worries me too, as it will be drilled and reamed for the same 6mm shaft.
Part of the problem is that I don't know what to expect and what would be considered acceptable, but I assume that I should be looking for a nice sliding fit with no lateral play. Am I correct?

Meanwhile, I'm just going to temporarily admit defeat and order some 6mm silver steel, which hopefully will do the trick and at the very least will give me a baseline idea of how well these things can be expected to fit together 'off the shelf'. For all I know at this point it still might not be perfect... That said, it does occur to me that keeping a small stock of round bars of various diameters might be smarter than turning down to diameter every time one wants to make a straight shaft.

Overall, a humbling experience showing me that I have a lot to learn about accurate turning. I'll need to up my game when it comes to the piston on this engine and all kinds of parts on subsequent builds  :-\ . Any advice welcome...

So, the picture shows the story so far, but tbh I had hoped to be further on at this point. But having spent a day and a half sanding and varnishing floors this week I can probably feel justified in some extra shop time over the weekend...

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825193.jpg)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: AOG on February 22, 2019, 12:45:03 AM
Welcome to the fun. Fits and clearances are something I still struggle with to a certain extent. In general terms being a little undersized is ok. Putting a 6mm shaft into a 6mm hole is a press fit. That is not what you want on your bearings. I usually try to be 2-3 thousands of an in ( about .05 to .07 mm if my math is correct ) smaller for a bearing fit. I use the same fit on my flywheels. The reality is that when I started I was lucky if I could hold +/-  8-10 thousandths (.2 - .25 mm) on my first few engines and they worked just fine. Your fits will improve with time and experience.

Tony
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: steamer on February 22, 2019, 12:45:45 AM
Parts look great to me Gary!   keep em coming!    8)

If it goes round and round and up and down....it's right.

Dave
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: steamer on February 22, 2019, 12:46:43 AM
And dont be afraid to say....Hey!?    Glad to help...everyone is.

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on February 22, 2019, 01:04:59 AM
Nice looking parts Gary. It's all about learning, and it really never ends. Still following your adventures and progress.

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 22, 2019, 09:31:05 AM
Welcome to the fun. Fits and clearances are something I still struggle with to a certain extent. In general terms being a little undersized is ok. Putting a 6mm shaft into a 6mm hole is a press fit. That is not what you want on your bearings. I usually try to be 2-3 thousands of an in ( about .05 to .07 mm if my math is correct ) smaller for a bearing fit. I use the same fit on my flywheels. The reality is that when I started I was lucky if I could hold +/-  8-10 thousandths (.2 - .25 mm) on my first few engines and they worked just fine. Your fits will improve with time and experience.

Tony

@ Tony - that is very reassuring. Much appreciated. TBH I was thinking that maybe it's just me. I don't mind having a learning curve to negotiate, which is different from feeling a failure and giving up (which I have no intention of doing). Knowing that you and others have been there too gives me vital encouragement. What I'll do now is shift to other parts until the 6mm steel arrives, then look at my options for the shaft when it does. Will report back on that later.

@ Dave and Bill - thanks for the encouragement. It helps, and really is appreciated   :ThumbsUp: :ThumbsUp:

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: steamer on February 22, 2019, 10:21:11 AM
Gary, and others

Consider the good book!     Machinery's Handbook.

https://www.amazon.com/s/?ie=UTF8&keywords=machinery%27s+handbook&tag=googhydr-20&index=aps&hvadid=213926653103&hvpos=1t1&hvnetw=g&hvrand=15141559827872613349&hvpone=&hvptwo=&hvqmt=e&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9001782&hvtargid=kwd-324143135994&ref=pd_sl_9bh0gjicgc_e

Many of the answers you seek....such as press fit tolerances....can be found there.   Good Stuff    the 23rd edition has been next to me since 88'  8)

Dave
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on February 22, 2019, 10:21:45 AM
Gary, I've found that for making crankshafts etc where accurate running is necessary it is better just to buy silver steel of the required diameter, it's hardly worth the effort of turning down the diameter. I bought a metric set of budget reamers from Tracy Tools, they didn't cost the earth and cover exact mm sizes from 3mm to 12mm, for the price I paid they have been a great buy.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 22, 2019, 10:49:22 AM
@ Dave - yes, Machinery's handbook looks like a great resource, though it could be almost a bit too comprehensive for a rookie like me. I might try to find something similar but a bit less expensive in the first instance, if such a thing exists. I notice that one of the editions of Machinery's has an 'expanded metric section'. Metric would be a criterion for me, though info on imperial would also be useful.  :ThumbsUp:

@ Peter - I was hoping someone would say that. I feel relieved! It would be great to have a small bespoke rack holding lengths of silver steel of various diameters, just to pick out what you need  :)

That said, having drilled and reamed a 6mm hole, might I not find that when the 6mm silver steel arrives it makes a press fit in it (which as Tony notes above is of course no good for a bearing)? Maybe will  just have to suck it and see...

I got my reamers from Tracy Tools too - not the set, but all the metric sizes I need for this engine. No doubt will be acquiring more in the future...

Another question - do you harden your silver steel shafts or do you just use it as it comes?

Cheers,

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: steamer on February 22, 2019, 10:57:56 AM
umm   OK.    If I come up with something less comprehensive I'll let you know..    by the way, google is your friend.   Hunt around and I'm sure you can find old copies in PDF  format for free.

Dave
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 22, 2019, 11:00:25 AM
Thanks Dave. Good point - I'll have a browse for it later online. Free pdf sounds good to me    :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Jasonb on February 22, 2019, 11:04:54 AM
Most reamers you buy in the UK will be H7 or H8 tolerance, with H8 being slightly looser and they will give a fit that is fine for a shaft run rotate in with minimal play. This will vary a tiny amount depending on meterial being cut, pilot drill size and condition of reamer. This is why I don't like to ream flywheels as the slight clearance can cause a wobble.

If you want a press fit then if you have hand reamers you can take advantage of the long tapered lead in and not go all the way through, machine reamers won't do this. On little engines like this Loctite is your friend.

I tend to use PGMS - Precision ground Mild Steel which is easier to work than silver steel particularly if you need to thread it. If I did use Silver steel I would not harden it.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on February 22, 2019, 11:06:08 AM
Not really Machinerys Handbook but you may find some interesting reading here :

http://campkahler.com/files/How_to_Run_a_Lathe_SB_1of2.pdf

http://campkahler.com/files/How_to_Run_a_Lathe_SB_2of2.pdf
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Ramon on February 22, 2019, 11:08:14 AM
Gary - you'll probably find your silver steel will be a tight fit as stock as said by Tony but that's not a real problem to overcome.

Firstly - just check the ends of the piece of silver steel - sometimes it is cut off with a grinding wheel and this can harden the very end by it's action. Just cut off the first 5-6mm off the end. Cut a piece long enough for your shaft plus a piece for chucking. Hold in the lathe and just reduce the diameter with emery - about 240 grit. Failing emery you can use wet and dry but this will not last as effective as emery to do this. Begin dry and then use light oil as a lube.  Make sure you have a small chamfer on the end of the shaft and keep trying the shaft - gently at first until it will slide nicely in it's bearing. This will give you the nice running fir required. If you can back the abrasive with something nice and flat that will give you better control. Make sure you clean the shaft each time otherwise any grit from the process will bind and give you a false impression

If you are canny you'll just do the area that fits the bearing leaving the stock size to Loctite into your crank disc  ;)

Good luck - you're doing fine

Tug
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: steamer on February 22, 2019, 11:14:27 AM
Not really Machinerys Handbook but you may find some interesting reading here :

http://campkahler.com/files/How_to_Run_a_Lathe_SB_1of2.pdf

http://campkahler.com/files/How_to_Run_a_Lathe_SB_2of2.pdf

Always good stuff!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: steamer on February 22, 2019, 11:17:59 AM
Most reamers you buy in the UK will be H7 or H8 tolerance, with H8 being slightly looser and they will give a fit that is fine for a shaft run rotate in with minimal play. This will vary a tiny amount depending on meterial being cut, pilot drill size and condition of reamer. This is why I don't like to ream flywheels as the slight clearance can cause a wobble.

If you want a press fit then if you have hand reamers you can take advantage of the long tapered lead in and not go all the way through, machine reamers won't do this. On little engines like this Loctite is your friend.

I tend to use PGMS - Precision ground Mild Steel which is easier to work than silver steel particularly if you need to thread it. If I did use Silver steel I would not harden it.

Additionally, pay attention to which reamers you buy.   As Jason pointed out, they come standard undersize, Standard Size and Standard Oversize.   As denoted by the ISO tolerance letter number that Jason has listed.    And Yes   Agreed about the Loctite!!!    used sparingly.

Dave
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 22, 2019, 11:26:55 AM
Thanks all.

@ Jason -I don't know what tolerance my reamers are but I will investigate. They are machine reamers. Once the steel arrives I'll have a better idea, and I take on board your point about precision ground steel. Next time!

@ Tug - I was using an abrasive paper and a flat piece of wood last night - not sure what it is; may be wet and dry: cheap, black in colour and sold by the sheet in various grades. It was working but I think I was expecting it to remove too much metal and I'd have been there all night  :-). Great advice though - I can see how emery would reduce that diameter to a sliding fit without it being too much of an ordeal. Thank you!

@ Peter and Dave - thanks for the info.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on February 22, 2019, 02:05:33 PM
Just as an aside re: shafting....if you know of an injection molder or mold maker nearby, ask them about cut off bits from ejector pins used in mold making. Typically these some in standard lengths and must be cut off to the mold's requirements. The cutoffs can be long enough in many cases to be used for shafting up to about 3/8". Ejector pins are case hardened and usually a few tenths undersized for a nice slip fit in a standard reamed hole. Their hardness also helps in terms of grub screws not digging into them.


Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on February 22, 2019, 02:17:17 PM
It looks like they can even be had from Amazon. Something like this is what I am talking about:

https://www.amazon.com/TCI-Nitrated-Straight-Diameter-Annealed/dp/B06Y3N4X1G/ref=sr_1_145?ie=UTF8&qid=1550844560&sr=8-145&keywords=ejector+pins

Looks for precision ground ones and nitride is even better. The above example seems to be for a package of 12. Other sizes, lengths, and metric are listed too if you look around amazon.

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 22, 2019, 02:32:16 PM
Thanks Bill.

The idea of that easy slip fit quite appeals. It's becoming clearer to me that the advantages of using a ready made bar of the correct diameter are widely recognised.

Will keep this in mind for the future.

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 24, 2019, 10:35:59 AM
Not a bad day yesterday.

I spent some time checking that the mill was in tram ( :ThumbsUp:), then aligned the lathe tailstock as precisely as I could. Found my new digital clock gauge to be very handy and user-friendly for these jobs.

Then, in keeping with the plans, I milled a flat on the cylinder to a depth of 2.5 mm:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825352.jpg)

The flat forms the port face but also creates an offset when held in a 3-jaw chuck which correctly positions the bore. I then drilled and reamed the bore to 12 mm (sorry no photos). The port face was cleaned up by some fine-grit sanding on the surface plate. The cap was then made via a simple turning operation. I'm quite pleased with the results. The outside of the cylinder ended up with a few marks but it should be easy enough to deal with them at a later stage:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825353.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825354.jpg)

Back out to the shop again shortly to continue...

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on February 24, 2019, 01:07:19 PM
Gary, that is an interesting vise you are using on the mill. Any information on it? Manufacturer, etc? The cylinder looks good too!!

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 24, 2019, 02:20:13 PM
Hi Bill -

I don't know the make of the vice and it doesn't seem to have any manufacturer's markings on it (though I will check the underside of the base when I take it off the mill). It's almost certainly British and of a fair age. It came with my Dore Westbury milling machine http://www.lathes.co.uk/dore-westbury/ (http://www.lathes.co.uk/dore-westbury/) and that mill was made in the late 1960's or possibly early 70's. The vice probably isn't bespoke to the DW though. My DW is currently at my place in France, awaiting a bearing change and a new motor. The vice is really good - well-made and accurate, as things were in those days.

Thank you re the cylinder.

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on February 24, 2019, 09:27:21 PM
Taking shape nicely Gary, a bit of drilling and making the piston/conrod then you are nearly there.

What is your intention with the piston? I know most small oscillators don't have rings but I found a shallow groove to accommodate a bit of graphite yarn helps. Even if it doesn't work you'll have an oil groove that won't do any harm.

Soon be time to get your boiler earning its living  :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 24, 2019, 09:46:43 PM
Yep, getting there Peter, and another post to follow this one.

My aim is to make the piston and con rod in one piece. I hadn't given the graphite yarn / groove question any thought, but it sounds like a good idea - thanks.

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 24, 2019, 10:12:26 PM
I have a box full of stainless steel M2 cap head screws complete with taps and tapping and clearance drills which I had built up for a currently sidelined project, These came in very handy today. In order to drill the three clearance holes in the cylinder cap for the fixing screws, I used my cheapo Dremel clone on its stand with a small rotary table fitted with a 4-jaw self-centring chuck and a dividing plate:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825417.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825416.jpg)

The drilled cap was then used as a template for drilling the holes in the cylinder. I followed the usual common-sensical procedure  of drilling and tapping one hole first and fixing the cap before drilling the other two. I did the tapping on the mill using a piloted spindle tap wrench. Taking no chances with these small taps!  :ShakeHead:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825415.jpg)

The result:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825414.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825413.jpg)

I then turned the main bearing from some round bronze bar, leaving the flange some 5mm wider than in Steve's plans to make a bit more of a feature of it given that my standard is wider than the original. Again, the clearance holes were drilled on the Dremel clone dividing setup:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825419.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825418.jpg)

Quite a satisfying day's work. I'm getting hooked on this...
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on February 24, 2019, 10:36:54 PM
Yup, you are hooked! Welcome to the club!!   :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 24, 2019, 11:02:39 PM
Cheers Chris. Pleased to be a member.   :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Kim on February 25, 2019, 02:31:36 AM
Looking great, Gary!  You're making good progress  :ThumbsUp:
Kim
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 25, 2019, 09:30:11 AM
Thanks Kim.

 :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on February 25, 2019, 01:04:21 PM
The cylinder cap holes look good. Just curious, why use the Dremel for the cap holes rather than the mill?

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 25, 2019, 01:50:24 PM
Good question.

I have found that some standard drill chucks don't hold very small bits very well, while the Dremel type tool uses small collets specific to bit sizes.

In fairness, though, I haven't tried the drill chuck that came with the mill on such a small size, so it may actually be fine. However, I knew the Dremel would work, so I used it.

Just habit really.  :)

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 25, 2019, 11:45:19 PM
The silver steel arrived today - 6mm for the main shaft and 3mm for the crankpin.

I tried the flywheel on it and found that it still made a loose, rattly fit. I'm not sure why this was the case, but there it was. Strange, because the bronze main bearing - which was drilled and reamed with the same tools - was at first reluctant to even go on the same shaft.  I was initially dismayed, but this gave way to the idea of drilling out the central hole of the flywheel and bushing it. This may be a blessing in disguise, I thought, because the bush could also be extended as a boss on one side of the wheel which could be cross-drilled and tapped for a grub screw - something which I had fancied from the start but for which there was previously no room for on the hub of the wheel.

So... I drilled and reamed the flywheel to 12mm:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825492.jpg)

I then turned a bush from brass which was drilled and reamed to 6mm. This is a stepped part with a narrow section of just under 12mm which goes through the new bore of the wheel. I followed Ramon's advice on page 5 of this thread for using abrasives to creep up on a diameter, and it worked a treat on the bush. The wider section of the part is of a similar diameter to the existing hub of the wheel, and this was cross-drilled and tapped M4:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825493.jpg)

 For the cross-drilling I used my new DRO for the very first time, in conjunction with an edge finder to locate the centre of the boss. So far I have only installed the DRO on the Y axis (waiting for material to arrive to make a mounting bracket for the X), but one axis was all  that was needed for this. It gave me a sense of what a fabulous thing a DRO is...

The part was then glued into the flywheel with Loctite. Well, not Loctite... 'Interseals R41 Bearing Fit', which Interseals tell me is just as good as Loctite but less expensive. Well, we shall see:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825489.jpg)

The photo below gives a sense of the part in situ in the flywheel. The long section at the 'back' of the wheel can easily be reduced or turned off later. The boss is also possibly a bit on the long side so it can also be reduced a bit if it will improve the look:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825490.jpg)

Finally, here are the flywheel and the main bearing temporarily mounted on the 6mm silver steel, just for show. They both now make a lovely sliding fit with no lateral play:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825491.jpg)

If the grub screw arrangement causes any wobble problems I can always still Loctite the wheel to the shaft, but I'm hoping that won't be necessary and of course there is more work to be done using an ER-32 collet chuck in the lathe to persuade it to run true.

gary





Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: steamer on February 26, 2019, 12:12:30 AM
Gary,  next time you try reaming a hole, slow everything way down, and feed gently and deliberately.   Once you feel it go through, STOP the lathe...like immediately.

Then back the reamer out with the spindle stopped.

I've had way better luck using reamers like that... 

Dave
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 26, 2019, 12:28:49 AM
Dave -

I did slow the lathe down and fed slowly.

However, I didn't stop the lathe immediately and I *think* it was still running when I backed it out. Maybe that's why the hole in the flywheel was too big initally. It's sorted now, though.

Thanks for the tip!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: steamer on February 26, 2019, 12:31:52 AM
Dave -

I did slow the lathe down and fed slowly.

However, I didn't stop the lathe immediately and I *think* it was still running when I backed it out. Maybe that's why the hole in the flywheel was too big initally. It's sorted now, though.

Thanks for the tip!

That's happened to me before.  What I think happens is a chip gets between the bore and the reamer on the way back out, and pushes the reamer sideways, and makes the opposite side cut in deeper.        A way to get a reamer to cut bigger, is with a cigarette paper.    Zig Zags are 0.0008" thick, if you put it on a tooth of the reamer, it will make it cut slightly bigger....but exactly how much is a little bit vague.  Depends on material.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 26, 2019, 12:35:49 AM
Wow.. I'd never have thought of that. Could be what happened I guess.

Tricks of the trade as well!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: steamer on February 26, 2019, 12:39:40 AM
Well...I got the opportunity to tell you because John Klunk   ( yeah that was his real name  Native American, and one of the best Manufacturing Engineers at Heald machine) taught me.     Each one teach one.

Oh and with the paper trick...run the reamer through without it first obviously....the paper is just a little "push"..

Dave
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 26, 2019, 12:44:49 AM
Makes sense all the same.

My main bearing (unlike the flywheel) was too tight on the shaft at first. I just ran the same reamer through it a couple of times more and now it's fine.

I haven't used reamers very much in the past, but it seems they're like everything else - they have a 'feel' to them that you have to learn...

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: steamer on February 26, 2019, 12:49:01 AM
You should try a D bit or a tool makers reamer.    They work fantastic.   Very predictable.

And if you make them, they're cheap as dirt!

Dave
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 26, 2019, 12:57:05 AM
OK - will keep in mind for the future.

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 26, 2019, 11:05:59 PM
More work on the flywheel today. First, I turned off the protruding section of the bush that I glued in last night with 'Interseals Loctite', and turned down the boss to make it a bit smaller.

Next, a flat was milled on the shaft to provide a positive location for a grub screw, and the conical end of an M4 grub screw was ground off (using my new vintage hand vice for the first time  :) ) to form a flat end to bear against the flat on the shaft. This did not add any appreciable wobble and the wheel feels rock solid on the shaft.

The flywheel and shaft assembly was held in the lathe with an ER-32 collet chuck in the headstock and a live centre at the other end:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825553.jpg)

The turning commenced with some chatter at first, but this reduced with the diameter, which I turned down to 55mm. This is 5mm wider than the plans call for, because the original by Steve is a solid disc, whereas mine has some detailing which removes mass, the extra diameter being intended to compensate for this.

The outer aspect and sides of the rim posed few problems and soon ran true, but the recesses were tricky and there was a slight wobble on the inner rim on each side. This is where 'wet and dry' sandpaper and a spot of cutting oil came into their own. I worked away at the recesses for quite some time with this and it occurred to me how valuable an adjunct to turning tools abrasives are. There are still a couple of marks which run out of true and I may go back and  fix these later but overall the wheel is good and as far as I can see the wheel and shaft assembly is sound and runs true. My intention is to never take the flywheel off the shaft again unless I have to.

Next, over to the mill and rotary table dividing setup to make a six-hole pitch circle:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825552.jpg)

... and the flywheel / shaft assembly more or less complete (with bearing):

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825551.jpg)

At this stage I'm quite happy with It. Both ends of the shaft will be shortened but the end you can see will be left sticking out a bit because I've a notion of putting a pulley on it...

I also honed the cylinder this evening, using two 12mm 'Flex-Hones' (120 grit then 240). These are imported from the USA and not easy to find here. They're damn expensive but I just decided to go for it instead of the split dowel method as sometimes time is more valuable than money. They left the recommended cross-hatched pattern on the inside of the cylinder. No photos of this, as they were all blurry.

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on February 26, 2019, 11:11:07 PM
Very nice Gary. Flywheel run-out can be annoying, but sounds like you have it sorted out well!!

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 26, 2019, 11:14:53 PM
Cheers Bill.

Prevention is better than cure, I reckon, though sorting out the inner rim was a bit of a mission. A wobbly flywheel would drive me crazy though!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on February 26, 2019, 11:21:05 PM
I hear ya Gary. A bit on the inner rim isn't nearly as visible though, but the main thing is you are happy with it.

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 26, 2019, 11:41:42 PM
Happy enough for now, Bill.

If the inner rim bugs me over time I'll go back to it...

Thanks for your interest.

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: bent on February 27, 2019, 04:24:15 PM
Dunno why the brush hones are expensive overseas - $20 for typical sub-inch sizes here, and available in all kinds of grit sizes and materials (aluminum oxide is a preferred grit for brass/bronze/aluminum over the more common silicon carbide hones).  If you pay substantially more than that for a 12mm hone, we should set up an import business and make a killing.  The shop I work for will hone/deburr about a thousand parts before the hones see any significant wear, so we consider them pretty cheap tool for what they do.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on February 27, 2019, 09:51:15 PM
Hi -

I paid $82 worth of British pounds for two brushes (including postage and packing).

I found that hardly anyone over here sells them, so those who do can charge what they like.

 ::)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 03, 2019, 11:00:45 AM
Gary, the Flex hones are relatively easy to buy in the UK in a 12mm size, not sure how good they are though ?

https://www.machinemart.co.uk/p/gunson-77075-3-piece-flexible-honing-brush-se/

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 03, 2019, 11:16:35 AM
Damn! I searched, but only found the more expensive ones that I bought. Somehow managed to miss these. Whether they are as good, who knows, but at the price I'd have bought them and saved myself fifty quid. And it's not like I'll be using them much because my future engines will be bigger. Maybe for spool valve cylinders though I suppose...
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 03, 2019, 11:23:17 AM
Damn! I searched, but only found the more expensive ones that I bought. Somehow managed to miss these. Whether they are as good, who knows, but at the price I'd have bought them and saved myself fifty quid. And it's not like I'll be using them much because my future engines will be bigger. Maybe for spool valve cylinders though I suppose...

Ebay has quite a few also  :)

On a slightly different note, I recently ordered the new Sealey Tools catalogue, it's free for the asking on their website. It arrived yesterday - all 1200 pages of it - The only snag is there are no prices in it. Definately worth a few seconds to email them for a copy though.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 03, 2019, 01:34:36 PM
Ah... must have had an impatience-based blind spot that cost me 50 quid.

On ebay all I saw were the kind of cylinder hones with three stones and they all seemed to be too big for my purposes. Never mind... my next engine will have twice the bore and I'll look more closely when it comes to cylinder hones.

The Sealey catalogue sounds good. I love leafing through catalogues, dreaming about having room for all the tools that are in them...
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 03, 2019, 11:34:07 PM
Next up was the piston. In Steve's plans the piston, con rod and big end are all machined from one piece of brass, and the forms are all left cylindrical. I also made mine from a single piece of brass, but added a couple of details, just for the look.

Some curves at the ends of the con rod, cut with my new round-tipped carbide profiling tool (which I already love):

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825944.jpg)

And a flattened big end:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825943.jpg)

I ruined my first effort by making it too short. No idea why it happened, but there we are. I gave it to my dear lady to put on her keyring. The second effort seems fine. I had been quite anxious about making the piston, thinking that it would probably be beyond me to make a piston and cylinder that fit together. However, it was surprisingly easy, just coming in slow on that final dimension with a fine grit paper, a flat stick and some oil. Both pistons (the reject and the good one) create a good vacuum in the cylinder, springing back up when pushed down, or making a nice 'plup' sound when pulled out with a thumb over the other end of the bore. A good step forward:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825941.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825942.jpg)

That done, I started on the crank. A slice of bronze was marked out and drilled:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825940.jpg)

Now, in the plans the crank is just a circular disc, but I have always liked the look of the crank on Ade Swash's 'Cornish Blue Pepperpot Wobbler'

https://www.youtube.com/watch?v=nIKJXt2b8yQ (https://www.youtube.com/watch?v=nIKJXt2b8yQ)

so I thought I'd have a go at making something similar. I sawed, filed and sanded it by hand, then milled the groove on the rotary table with a round-nosed endmill. The inherent inaccuracies in my bench work caused the hole for the crank pin to end up slightly out of alignment (i.e. nice and perpendicular but not quite in the right place). However, the two holes are the correct distance apart and I reckon that once the thing is assembled it will be hidden by the big end and even I won't notice it. Overall, I'm pretty pleased with it:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825947.jpg)

Here it is with the 3mm silver steel crank pin Loctited ('Intersealed') in place:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825946.jpg)

And here jury-rigged on the end of the main shaft, just for fun:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/825945.jpg)

Both the main shaft and the crank pin will be cut to the correct length at the end of the build.

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on March 04, 2019, 12:24:16 AM
I like that crank too Gary. Ade's engine in a fine looking oscillator too. I can see why you like it.

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 04, 2019, 12:41:05 AM
Yeah - these little touches can make all the difference.

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 04, 2019, 12:49:26 AM
Its looking good  :)

Not long now before we can see it running on the hot stuff.

Are you going to invite us all round for a cheese and wine evening to celebrate the inaugural steam up  ;)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 04, 2019, 12:56:09 AM
Are you going to invite us all round for a cheese and wine evening to celebrate the inaugural steam up  ;)

Of course - but it will be at your own risk. The boiler hasn't been inspected, so it's likely to explode   :wine1: :Mad:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Tennessee Whiskey on March 04, 2019, 01:01:45 AM
Fireworks, wine, cheese, what more could you ask for?  :Jester: Looks great gary.

Cletus
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 04, 2019, 09:42:41 AM
Pressure, scalding heat, metal parts at high velocity, and alcohol.

What could possibly go wrong?

Cheers Eric  :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: JC54 on March 04, 2019, 06:46:12 PM
Evening Gary, really like your piston/conrod, it took me 5 attempts to get mine as I wanted it. Have I led a sheltered life or is the turning tool that you used a common item? Enjoying your build, been there on this engine... but made a lot more mistakes... :embarassed: :old: :DrinkPint: John
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: bent on March 04, 2019, 06:52:29 PM
That is a neat looking crank, may have to try that sometime - thanks Gary!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 04, 2019, 10:50:33 PM
Many thanks guys.

@ John - I'm not sure how common the round nosed tools are, but I'm already sold on mine having had them a few days. I got them from RDG tools.
There are still a few opportunties for me to make mistakes on this build - see my next post   :disappointed:

@ bent - thank you.. The credit goes to Ade Swash on youtube.

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 05, 2019, 12:13:09 AM
Pulleys.

With a pulley, an engine bespeaks connectedness and possibility. It is not a closed system. Even a little half inch wobbler - which may never actually drive anything other than itself - takes on a more 'networked' aspect with the addition of a pulley. So, while waiting for some other bits and pieces to arrive, I set about making one.

Drawing inspiration from my new round-nosed carbide tools, I ordered two small round drive belts from an interesting company called Motionco. This was just to gauge the size of the pulley groove, which was just as well as I didn't think to order a sensible length and so ended up with the below, which are fine for sizing purposes but not much else. My bad.

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826027.jpg)

The bigger of the two is far too big for this engine, and the smaller may be too small for the groove cut by the smaller tool. We shall see. I can always buy a belt somewhere between the two if I ever actually hook anything to the engine.

I started making a pulley out of aluminium bar (to contrast with the brass flywheel):

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826025.jpg)

This came together quite quickly and was finished on the shaft with the flywheel, resulting in two wheels turning together with zero wobble:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826026.jpg)

Result!

Then disaster struck. Like a damn fool I impulsively decided to shorten the protruding length of the shaft you can see in the picture above by facing it (I know...). The tool caught the end and bent the shaft.  :ShakeHead: I took it apart and tried to salvage a straight piece, but to no avail. Two wobbly wheels until yesterday's order of more silver steel arrives, with me on tenterhooks until it does.

Bent shaft notwithstanding, today's progress:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826029.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826028.jpg)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 05, 2019, 12:29:05 AM
That's a pain that you ruined the shaft, but I guess you can take comfort in knowing nearly everyone else has done the same.  :(

As for drive belts if yours are unsuitable others can be bought here :-

https://www.glrkennions.co.uk/belting.html

https://www.maidstone-engineering.com/materials/misc-materials

Not sure how well the jointed GLR ones work on a tight radius though.

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 05, 2019, 12:34:00 AM
Oh yes, been there, done that!  Great progress still!


 :popcorn:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on March 05, 2019, 12:36:12 AM
What a bummer Gary. Hope it left the pulley and flywheel bores undisturbed though.

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 05, 2019, 12:59:37 AM
Thanks Gentlemen.

@ Peter - the test belts in the picture do seem a bit hard, but perhaps longer ones would soften up with a bit of handling and provide some grip. If not, there are options as you suggest.

@ Chris - thanks.

@ Bill - I hope so too. It'll be bleak if the bores are knackered. However, I think they are probably ok. In fact, thinking it through, after the screwup I cut what I thought was an undamaged part of the shaft (it was behind the ER-32 collet when it happened), put the wheels on and just nipped up the grub screws and it seemed to be running true again. I then took the wheels off, milled flats on the shaft for the grubscrews, reassembled, and it seemed to be only after that that it wobbled. I admit I was perhaps a bit overenthusiastic in milling the flats - each one down 1mm, on opposite sides of the shaft. More like notches really. I'm now wondering if this distorted the bar by creating or relieving stresses in the steel (or even just mechanically bent the bar by taking too-heavy cuts). It didn't happen the first time, but still...

I hope that new 6mm bar arrives tomorrow!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: steamer on March 05, 2019, 01:41:27 AM
Hey Gary

My very first crank...turned on a AA109...I was on the last cut, and I fouled the tool...BANG!   Instant pretzel....I was gutted....

I took it to work, and I showed one of my machinist friends in the prototype shop...."Think we can straighten it?
"
He picks up a babbit hammer and gives it a mighty WACK!..........     I say hmmm    Looks good!....I put it between centers   0.003" run out.....I called it done!!

 :lolb:

If you have issues after this when the new shaft comes in...post it up ...we'll talk ya through it. 8)

Dave
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Jasonb on March 05, 2019, 07:08:25 AM
It's coming along well Gary

You may want to think about swapping the pulley around so the forces from the belt are not as far from the bearing, as you only have a single bearing any pull from a belt will tend to make the bearings bind. Also diameter could be another issue, smaller the pulley the more mechanical advantage the poor little engine will have - think of a Mamod with the pully groove cut into the flywheel's hub.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 05, 2019, 09:32:17 AM
@ Dave - yes - it's that horrible moment of realization, when you hope you just imagined it but really know that you didn't.
I could try whacking mine with a hammer but I don't have the Jedi touch that your friend does. I'd be at it for 10,000 years and still it wouldn't be straight.

@Jason - thanks. I'd be a fool to ignore your advice. I'll reverse the pulley and reduce the diameter (perhaps not to Mamod-like dimension but a bit less chunky than it is now).

This morning when I woke up, I suddenly remembered what probably caused the runout after the initial mishap. Having shortened the bent shaft and re-chucked the assembly, it ran true. However, after I had milled the flats it didn't. It came into my mind that while the shaft was held horizontally in the rotary table chuck for milling, I was changing chucks in the mill and I accidentally dinged the shaft with one of them. That's probably what did it, though I convinced myself at the time that it wasn't hard enough (the power of denial!). Fortunately the pulley and flywheel were lying on the bench at the time so the bores *should* be ok...  ;)

Strange, the way that memory works (or doesn't, as the case may be...).
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 05, 2019, 10:17:28 PM
Today's endeavours:

The new silver steel didn't arrive but I found an undamaged offcut from the original piece. Flats (shallower than last time) were milled for the grub screws and the flywheel and pulley were mounted on the shaft, with the pulley the other way round as per Jason's advice. A very fine skim cut saw the flywheel running true, and the diameter of the pulley was significantly reduced (again as suggested by Jason):

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826097.jpg)

Then, moving on, I marked out a piece of French walnut which in due course will become a sub-base for the engine. This was from a tree at my place in France that sadly I had to have cut down as it was too near the house and threatening to do damage. The upside was that I now have a supply of walnut that will last me for years. Never thought any of it would end up supporting a steam engine though:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826096.jpg)

Next, I broke out the yummilishious red layout dye ( DO NOT :wine1: !!!) and did some initial measuring and marking out on the standard. Ramon advised me that a brass cylinder oscillating against an aluminium port block is not ideal, and suggested that I make a brass wear plate. It appears in situ (but not attached) in this photo:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826095.jpg)

The plate is cut from thin brass sheet and it was much easier to shape than I thought it would be (pair of snips and a small drum sander in the drill press). After shaping it was a bit bent, but responded well to a small planishing hammer applied to the reverse side on the anvil of the vice. Now it is in the vice, being squeezed mightily for a couple of days between two flat pieces of wood (which at the very least will do no harm). The plan is to fix it to the frame with epoxy and tiny cap head screws, but as you can see it will first require some fine sanding and polishing to achieve the appropriate surface quality:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826094.jpg)

Finally, the story so far:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826093.jpg)

Many thanks to all you guys for your support with this simple build. Even though your skills are way beyond the level of single-acting oscillators, so many of you have checked in to this thread with encouragement and sound advice. I truly appreciate it.

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on March 05, 2019, 10:36:50 PM
Looking great Gary. The wear plate should work well no more that the engine will run. The main thing is lubrication between the cylinder and wear plate, that will help as much as anything. Love the walnut btw.

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 05, 2019, 10:47:15 PM
Fine progress Gary!

One thing I like to do on mating surfaces like your cylinder and plate is to lap them on a diamond stone to be dead flat and no bumps. I have a couple different grits that I bought for sharpening chisels and plane blades, they are flat steel plates with the surface covered with diamond grit. You can do the same thing with a sheet of fine emery paper taped to a glass plate, or use diamond lapping paste on the sole of a wood plane (have one I use for that which is no longer used for wood work).
 :popcorn:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 05, 2019, 10:57:30 PM
Many thanks both.  :ThumbsUp:

@ Chris - is this the kind of thing you mean? :

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826100.jpg)

If so, I have one for sharpening wood chisels. Should I use it with water for the port face and wear plate?
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 05, 2019, 11:02:28 PM
Taking shape nicely  :)

I can see the thinking behind the wear plate but my only concern is if it allows leakage between the plate and the aluminium upright. I guess with air it wont be noticable but it you want to run it on your boiler I think you'd need to solder some sort of intake tube (and probably exhaust) to penetrate into the aluminium with a leak proof seal.

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 05, 2019, 11:10:54 PM
Ah... the plot thickens!   :stir:

Peter, I will be running it on steam. After Tug suggested the wear plate my thought was just to give it a good thick coat of epoxy, stick it on, clamp it until it sets, put screws in for good measure (and appearance), then drill the ports and pivot hole through the brass, epoxy and ali in a oner. In other words with the epoxy forming a seal.

Wouldn't that work? Or would the wet steam mess with the epoxy? And if so, I wonder if there's an alternative adhesive / sealant as the soldering idea sounds a bit fiddly...
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 05, 2019, 11:14:32 PM
The lapping plates I have are solid blocks, about 3/16" thick so no flexing. Not sure how rigid the one you showed is. If it can flex its no good, you would wind up with a curved plate. I use mine with oil to float off the metal dust.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 05, 2019, 11:17:34 PM
Chris -

Under the steel it's hard plastic so I think it's pretty rigid, but I will check.

Thanks again,

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 05, 2019, 11:20:17 PM
I appreciate that the steam wont be of high pressure but knowing how steam highlights even the tiniest of leaks I think you'll get leakage around the plate, on a little engine like this it isn't really going to affect performance but as you've taken care to make it attractive looking I think steam leakages may detract. The problem may be worsened if you apply load to the engine.

The thing to do is try it and see what happens  :headscratch:

Soldering shouldn't be a problem, I'm not sure where you intend to mount the intake but if it is on the back the same soldered tube could be the intake pipe.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 05, 2019, 11:29:36 PM
The thing to do is try it and see what happens  :headscratch:

I'll probably do that in the first instance Peter, but if there are leaks I'll be wanting to fix them so could consider the solder then.

I presume we're talking soft solder here if I go down that road?

 I'm waiting for some pipe-to-thread connectors to tap in as steam supply and exhaust. I'll see what they're like before deciding where to put them but straight in the back for them both would be my preference so as not to detract from the outline of the engine's shape.

Cheers   :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 05, 2019, 11:35:34 PM
It's got to be worth trying with your original intention, you haven't anything to lose.

I'm not sure how far the ports are apart (4mm?) but unless the epoxy holds up well it will be easy for the inlet steam to start finding it's way into the exhaust. Mind you that may give it a great V8 sound  ;)

I can't say I know a lot about epoxy but if it softens under heat could it block the ports ?
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Kim on March 06, 2019, 01:47:55 AM
Go with JB-Weld.  That's a high temp epoxy and should work well under heat.  That is, if you want to go the epoxy route.
Kim
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 06, 2019, 02:08:32 AM
Go with JB-Weld.  That's a high temp epoxy and should work well under heat.  That is, if you want to go the epoxy route.
Kim
Definitely, normal epoxy softens well well below steam temperatures, jb should be fine. Sand the mating surfaces with coarse grit to give it extra tooth, and be sure no oils on it.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 06, 2019, 07:26:31 AM
Thanks guys:

@ Peter for raising the question and suggesting an alternative method.

@ Kim and Chris for suggesting JB Weld.

I already have some Araldite 'Steel' epoxy for metals, but it only works up to 65 degrees C, so I have just ordered some JB Weld from Amazon (287 degreees C). Am working the next two days, so hopefully it will arrive by Friday when I'm off again...

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 10, 2019, 11:42:03 PM
It pains me when I am pulled away from the workshop at a weekend to fulfil other obligations. The sting is lessened, however, when these obligations include brewing 20 litres of Trappist-style pilsner:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826575.jpg)

I did get some time in the shop though. Following the advice of Chris, above, I looked to lapping the wear plate with a diamond-coated surface. As he thought may be the case, the diamond sharpening 'stone' that I already had (as in post #127 above) tended to flex and risked creating a curved surface, so I went to a local shop and bought this:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826574.jpg)

It is much more rigid than the other one, and has a coarse side and a fine side, though no specifications appear on the packet. To be honest, the job was trickier than I expected and I ended up using a 400 grit paper which seemed to create a better surface finish than the tool did. However, the wear plate got thinner to the point it was tending to flex as I lapped it, so I decided to stop:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826573.jpg)

 Perhaps it's fine, and I may have put in a lot of unnecessary work. Perhaps it's not fine. I decided the best thing was to leave it and see how it performs when I first hook up the engine to the boiler. If at that point it haemorrhages steam, it will probably be easier to lap it further when it's JB Welded to the standard than it was as a standalone. Equally, a new wear plate could be made and fixed on top of this one if this one is too uneven. But it might all be ok...

I'm guessing that the diamond tool could also be good for lapping pistons.

As the JB Weld hasn't arrived yet, I busied myself making the decorative holes at the top of the standard. These ranged from 12 mm down to 4 mm. They were marked out with a dry-wipe marker and a plastic drawing stencil featuring circles of many different sizes as well as other shapes. The centres were then picked out with a scriber, followed by an automatic centre punch  and a traditional centre punch. The wiggler was used to locate the punch marks, then they were centre-drilled and drilled to size. I was pretty careful to position these holes well, as one even slightly out of place would ruin the effect and make the whole engine look pretty clunky. Actually, I was pretty pleased by how it turned out:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826572.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826571.jpg)

 :cheers:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 11, 2019, 11:40:52 PM
Today it was time to embrace the sticky stuff.

JB Weld - 'America's Toughest Weld', according to the packet - so if it's good enough for gluing together the steel girders of Manhattan skyscrapers, it's good enough for me in my little shed in a remote corner of the British Isles.

I glued the standard and wear plate together and clamped the assembly between two pieces of hardwood:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826664.jpg)

While I was waiting for it to set I completed the installation of the DRO on the x axis of my mill, so I now have a functional DRO, give or take some fine adjustment and the fitting of protective covers. Now I can get some serious machining done on the little engine and bring it closer to completion...

After six hours I thought I'd take the clamps off the JB Welded assembly in case some of the adhesive had squeezed out on to the surface of the part. I assumed that it might still be relatively easy to remove any excess after that period of time rather than leave it overnight until the stuff was rock hard. This appears to have been a good call. At first I thought the thing had welded itself to one of the pieces of hardwood, but a little leverage with a screwdriver sorted that out. There was indeed surplus JB Weld on the surface of the standard and plate, but it came off easily enough. There's still a slight line of it round the plate but I decided not to disturb that until it has cured overnight. Meanwhile, it's back between clamps again.

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826663.jpg)

The next job tomorrow is to drill through the holes in the plate and tap for M2 cap head screws:



Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 12, 2019, 10:23:11 PM
A productive day today. First, I drilled and tapped holes for the screws at the edges of the wear plate. I was so relieved at not breaking the brittle M2 tap that I took my eye off the ball afterwards and sheared off the head of the bottom right screw (visible in picture below). Disappointing, but the screws are decorative anyway and it was easy enough to drill out the headless screw and JB Weld another one (actually longer) in as a pin. I then set up the standard properly on the mill, using both axes of the DRO (install completed yesterday) for the first time. I have to say that using a DRO is transformational... :whoohoo:

The main holes were then all drilled from the numbers on the readout. I diverged from Steve's original plans by making the hole for the cylinder pivot 8 mm diameter instead of 4 mm, as I plan to add a bronze bush due to the standard being aluminium. Also, I may make a composite pivot (suggested by Tug on page 2 of this thread) if I can fit everything in.

The plans specify a rectangular standard with the steam inlet on the top edge. Due to the shape of mine I decided to bring the steam in at a jaunty angle on the left side. The picture shows the drilling setup for this:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826717.jpg)

I was on tenterhooks drilling that L-shaped passage and at one point I thought I had misread the quill DRO and overshot into the exhaust, but fortunately that was just paranoia  :paranoia:

The resulting hole was then widened to sufficient depth and tapped to accommodate a pipe-to-thread connector to match the pipe from the steam valve on my boiler. It could be argued that this is out of scale with the engine but I have to say I like the effect:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826714.jpg)

The main bearing was also screwed to the flywheel side of the engine.

With the standard complete, I cut the crankshaft to length, pushed it through the bearing and Loctited the crank in place:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826716.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826718.jpg)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/826715.jpg)

Pleased to report that the flywheel and pulley run sweet and true. They are secured by grub screws so if I need to remove the crankshaft I'll  have to take them off given the crank is fixed with Loctite. This is something I'll avoid if possible as I'm afraid they may not run so nicely if I disturb them....
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 12, 2019, 10:36:26 PM
Looking good, you must be in a position now to try a test run   :)

The base reminds me of an old fashioned flat iron.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 12, 2019, 10:37:37 PM
Excellent!!  :popcorn:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 12, 2019, 10:59:25 PM
Thanks guys   :ThumbsUp:

@ Peter - I still have to make the pivot and nut, and find a suitable spring. Also not sure I did a great job on the wear plate, so it may need more work. Working next two days, so test run maybe beginning of next week...?

Agree the base looks like an iron, though each side is a different length   :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on March 13, 2019, 12:38:43 AM
It coming along well Gary. Looking forward to the run test.

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 13, 2019, 06:42:29 AM
Cheers Bill.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 16, 2019, 05:23:13 PM
Poked three more decorative holes through the bottom of the standard, then enlarged the hole for the pivot and made a bronze bush for it. I'm going with Ramon's suggestion of a composite pivot (page 2 of this thread). The bush made a press fit into the hole. First press fit I have ever done, and I'm well chuffed. Hitherto, I considered press fits to be highly esoteric and not the business of mere mortals like me. I pushed the bush in in my bench vice, and OK it's not the tightest press fit in the world, but I don't think it's going anywhere, and if it doesn't then it's a press fit in my book. And if I can do it once...   :)

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827004.jpg)

Only the pivot left to do, but that's tomorrow's job as now it's cider time!   :cheers:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 16, 2019, 06:19:55 PM
Coming along great - can't be too many more parts to do before first spin.
 :popcorn: :popcorn: :popcorn:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 16, 2019, 06:21:38 PM
Cheers Chris.

Just the pivot pin, the nut and the walnut base...

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 16, 2019, 06:41:35 PM
Cheers Chris.

Just the pivot pin, the nut and the walnut base...

 :ThumbsUp:

On the home straight now Gary  :)

Are you going to add some sort of exhaust pipe on the rear? I think even something like a short piece of brass pipe will enhance it even more.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 16, 2019, 06:46:24 PM
Hi Peter -

Yep... hoping to have it finished tomorrow (apart from the wooden base, which will need at least three coats of Danish oil).

Am planning to put a bit of copper pipe in as the exhaust which in due course will be extended and routed up the chimney of the boiler.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 17, 2019, 10:17:50 PM
Yep... hoping to have it finished tomorrow (apart from the wooden base, which will need at least three coats of Danish oil).

I knew I shouldn't have tempted providence like that.

The day started well as I began work on a composite pivot as suggested by Tug on page 2 above. The main section was turned from 8mm precision ground mild steel (tip from Jason), and the studs from 4mm stainless threaded bar. The nut also went well. I have only tried knurling twice before, without much success, but this time it went ok (youtube is my friend). Here is the nut half way through being made:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827180.jpg)

I also opened out the last few millimetres of the exhaust port at the back of the standard and added a curved copper pipe which will eventually be extended and routed up the boiler chimney (no photo).

Then a minor disaster befell me. There is only about 5mm between the port face of the cylinder and the bore. This only allows for a very short tapped hole for the pivot. The plans call for a 5BA thread but I don't have any BA taps so I just went with M4 - and stripped the thread by giving the wrench one twist too many   :facepalm:
This left me with a shallow, threadless hole with a rounded bottom. I decided to resort to JB weld:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827181.jpg)

I ground a point on the threaded stud to maximise the depth of penetration into the hole. The wider section of 8mm steel (which fits the bearing) is drilled, tapped and faced at both ends and sits flush with the port face so should stabilise the stud and hold it perpendicular to the face. Only the 4mm stud reaches down into the hole. There is JB weld between these two components for added stability (though this version loses Tug's composite pivot in which a loosely tapped thread allows wiggle room for the cylinder to bed against the port block).

The JBW is curing now, and I did clean off the excess that can be seen in the pic.

The problem is that only about 3mm of the stud, ground to a point, goes down into the hole and bottoms out. I know JB weld is good, but is it that good? In effect, this is little more than a butt joint in a location that receives a lot of torque.

I was wondering what to do if (when?) it shears. I'd rather not remake the cylinder (which might also mean another piston), so I came up with the idea of counterboring the hole down to about 3.5 mm with an 8mm endmill to create a flat-bottomed seat for a section of the 8mm bar, which would be pre-drilled and tapped for the 4mm stud. This assembly could then be fixed into place. I suspect the JB weld would do better on a joint of that kind.... or would I need to silver solder it... or could it be soft soldered...? Or perhaps Loctite...?

And of course, maybe I'm wrong and the JB weld fix that I am trying now might do the job.

I'd value your thoughts on any of this, and of course you may have ideas for a completely different way of doing it.  All suggestions welcome!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 17, 2019, 10:43:23 PM
Hi Gary, that's a pain that the threading didn't go to plan.  :(

I guess everyone will have a different solution but I'd be tempted to drill out the damaged thread to form a flat bottomed hole slightly larger (and as deep as you dare go), if you then turn a close fitting plug and secure it with Loctite 638 you ought to be able to redrill it.

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 17, 2019, 10:58:05 PM
Thanks Peter.

I take it the Loctite 638 would be ok at steam temperature?

Do you think that if Loctite and a plug would do, then maybe Loctite and the 8mm shaft straight into an 8mm diameter flat-bottomed hole would do too? It would save me the horror of drilling twice and tapping once...

There really isn't much metal there to work with and even my M4 plug tap doesn't really get going until it's in deeper than that (which contributed to the issue in the first place).
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 17, 2019, 11:09:33 PM
To be honest I'm not sure what the specs say about Loctite 638 but the pivot on my biggish wobbler is secured with it and I've steamed it many times and it is still solid. I guess on a real working application it may not be ideal but for a small ornamental engine that will only see light use I think it will be strong enough.

Do you mean have the 8mm cylinder secured solid to the cylinder and have it oscillating? I thought the 8mm was a fixed bush to be secured in the upright?
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 17, 2019, 11:16:58 PM
I just looked - it's good for 180 celcius.

I have some 603 which does for 150 degrees. Do you think that will do?

Yeah, I mean the 8mm fixed to the cylinder and oscillating. The bush in the upright is 8mm ID and 12 mm OD. The 8mm bar makes a nice running fit in it.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 17, 2019, 11:21:38 PM
638 seems to be better at filling gaps than 603 is though. 603 is more of an anaerobic thing.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 17, 2019, 11:27:07 PM
I don't know how hot the metal gets but as I say 638 seems to hold up without any problem. I've never used 603 but 638 cures in a lack of air (oxygen?) and is incredibly strong if there is a small space between the components for enough of the liquid to spread.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 17, 2019, 11:36:48 PM
The main difference seems to be that 603 is close-fitting but 638 will fill gaps up to about 0.25mm.

You'd need to be Alan Turing to crunch the numbers of all the different Loctites and know what each one does.

Meanwhile, my JB weld repair is beginning to cure and I'm still hoping against hope. JB weld is good, but it's not a promising joint. You never know though...
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: MJM460 on March 17, 2019, 11:56:42 PM
Hi Gary, there is actually not much torque on that joint, it can be a nicely sliding pinhole a bearing, as it is in the standard.  The main force is the axial spring force which is required to hold the cylinder against the standard.  The only torque is from the friction as the cylinder oscillates by rotating around that pin.  I have even seen designs where the cylinder is held against the port face by a spring pushing on the opposite side, so no axial force on the pin.

I would see no issue with using your milling cutter to enlarge the hole, providing you are very careful to set it up square in both directions.  (This is the critical step in which ever method you use to recover, take plenty of time and double check.)  But instead of using an 8 mm pivot, I would turn down the pivot section of the pin, perhaps to your original intended diameter, as the side forces on a smaller diameter pin will result in less torque resistance due to friction.  And you can then use your spring and nut without modification.  (Well done on that knurling, by the way).  The larger diameter insert in the cylinder gives the loctite more surface area to develop its shear strength.

Going well and not far to go,

MJM460

P S - For another time, I have found that an extra bottom tap, ground down on the end to minimise the lost thread, used after your normal plug or bottom tap helps with tapping those holes where the depth is limited.  But it is always a tricky job for those of us with less experience.  Maybe for the others too!

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 18, 2019, 12:29:55 AM
Hi MJM -

I initially made the pivot 8mm wide to make a composite pivot as suggested by Ramon on page 2.

However, due to today's events that has (at least temporarily) been shelved.

If I go back to a narrower pivot, I'll probably screw it into a plug before Loctiting the plug into a larger hole in the cylinder. That way I could avoid having to tap that thin wall and risk the same thing happening again. I'll also need to rebush the standard for a smaller pivot but no big deal there.

First, though, I'll wait and see if the present repair attempt works, and if it does I'll probably just keep the 8mm pivot. That of course remains to be seen.

On keeping it square - I nearly drove myself crazy obsessing over that today, and it looks like I may have to do so again!

Great suggestion about grinding the tap!

Thanks for your help,

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Jasonb on March 18, 2019, 07:02:23 AM
The JB Weld will hold, its only a weedy little spring that will be pulling against it, if in doubt look back at Ramon's tests on the stuff.

I've gone over to using Spiral Flute taps for almost everything metric now, just need the one and goes just about as deep as a plug tap
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 18, 2019, 08:20:46 AM
Jason -

having just checked it this morning I had pretty much come to the same conclusion. It seems to be pretty solid (and perpendicular  :))

Will definitely check out spiral flute taps.

Cheers   :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 18, 2019, 05:14:29 PM
Yay!

A great day for me   8)

My first engine, and it certainly won't be my last.

Here she is, 'Wasp', running on live steam:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827250.jpg)

Video to follow over the next day or so.

Just some fettling left to do and I still have to make the walnut base.

Thanks for all your support, guys. I wouldn't have been able to do it without you.

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 18, 2019, 05:30:41 PM
Yay, well done - it looks great  :)

Good to see we have lift off, I look forward to seeing a video.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 18, 2019, 06:28:07 PM
Excellent! Looking forward to the video!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: AOG on March 18, 2019, 06:28:59 PM
It looks great.

Tony
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Ramon on March 18, 2019, 07:53:59 PM
Congratulations Gary - absolutely top marks for an excellent build log and even more for your dedicated persistence in overcoming the issues and problems as they arose :ThumbsUp: :ThumbsUp:

There's nothing to beat any 'first run' except perhaps on that first runner made :) - well done indeed.

BTW nice save with the JB - I don't think you will have any issues, it's amazingly tough and resilient and at steam temperatures too.

As ''Nothing breeds success like success'' all the best for the next build whatever it may be  :ThumbsUp:

Regards -Tug



Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 19, 2019, 07:35:50 AM
Thanks, all - very kind of you.

As you'll see from the video that I'll post soon, it does leak quite a bit of steam around the ports. If you have any thoughts about whether I should do more work on the port face or just run it plenty on air and let it gradually fix itself as it wears in, I'd be keen to hear them.

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Robert Hornby on March 19, 2019, 07:49:24 AM
Well done Gary, very nice  :whoohoo: :cheers:
Robert
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 19, 2019, 07:52:13 AM
Thank you Robert!

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: PJW on March 19, 2019, 08:33:58 AM
Excellent job looks better than my first effort!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: MJM460 on March 19, 2019, 09:10:45 AM
Hi Gary, great to see you reaching a major milestone.  Well done.  Itís a great tribute to your attitude and persistence in overcoming the inevitable problems.

When you have the base done, do remember to make some neat piping to connect the engine to the boiler.  Then on to the next one.

MJM4607
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 19, 2019, 11:42:34 AM
Thank you guys for your kind words.

@MJM - I plan to return to the boiler now and make it perform and look as well as I can. Already have some nice elbows for the piping.  :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 19, 2019, 11:45:33 AM
Here's the video. I'd really appreciate any feedback you may have for me on how it performs, and on whether I need to do more work on the port faces or if it will just improve with wear.

I certainly need to learn to control the wild wee beastie that is the boiler, that's for sure!  :Mad:

http://www.youtube.com/watch?v=cp6Ja-6BrZg
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: cnr6400 on March 19, 2019, 12:18:25 PM
It's a runner! Congratulations!  :ThumbsUp: :ThumbsUp: :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on March 19, 2019, 12:34:56 PM
Well done Gary. It certainly runs very well from the video and has been a joy to   watch your progress on #1.

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 19, 2019, 12:57:42 PM
Well done! Not uncommon for a oscillator to leak a bit, takes very little uneveness on the two surfaces to leave a gap, should wear in. The spring pressure can make a difference even with a perfect fit. If you press in on the cylinder with air pressure on but the engine not running and the leak stops, needs more spring, if still leaks than it needs to be worn in. The metal right around the pivot is often the culprit, any round transition there can be filed off.


All round, great job!!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 19, 2019, 03:22:26 PM
Nice one Gary it looks and runs great  :)

All little wobblers like yours will leak a bit of steam so I wouldn't get caught up in altering things, it runs fine as it is. I agree with Chris about adjusting the spring pressure tho, you may find a bit of tweaking helps. A tiny bit of oil in the inlet now and again may help also.

Any thoughts yet on your next build?
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Jasonb on March 19, 2019, 04:18:22 PM
Running good

It would be worth taking apart to see where the most contact has taken place between cylinder and the port plate, it only needs for that pivot to be slightly out and one side won't seal as well as the other. If there is an obvious area of contact then that can be lapped down, this is where just having contact around the port area rather than the whole surface helps as there is less metal to lap away.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Kim on March 19, 2019, 05:38:52 PM
Congratulations Gary!  It's great to see your little oscillator running so well!
Kim
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 19, 2019, 09:05:32 PM
Thank you guys. I am reassured. Much appreciated!

@ Jason - I'll run it for a couple of weeks then take a look as you suggest.

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 19, 2019, 09:17:03 PM
Any thoughts yet on your next build?

I knew you would ask me that!   :Lol:

1. Finish the walnut base for this engine.
2. Finish DRO install on my mill by making protective covers for the scales.
3. Sort out the utterly chaotic mess that has consumed my workshop during the build. Small engine, big mess.
4. Test the Indian pressurizing kerosene stove as the heat source for this engine.
4. Optimise the boiler both functionally and visually.

and then...

5. I'm not done with single-acting oscillators yet. In due course I will move on to double-acting ones and fixed cylinder engines with valves. And of course there's the PMR #6 kit but that's further down the line again. However, for my next project I plan to build two single-acting oscillators at the same time.  Twice the size of this one (24 mm bore); one single cylinder and one twin. The main working components will be the same so I'll be able to get three times the benefit out of each setup. And again, the look and aesthetics will be a bit 'different'...
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 19, 2019, 10:26:27 PM
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827326.jpg)

 8)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: MJM460 on March 20, 2019, 12:54:39 AM
Hi Gary, great to see it running on steam with your boiler.  Certainly appropriate to be basking in the glory of that first run.

I believe it will already be worthwhile taking off the nut and spring to remove the cylinder and closely inspect the port face, I think you will already be able to see if the wear pattern is even around the ports or not.  I have found that each of my oscillating engines benefited from some extra work on the port faces of both the cylinder and the standard.  I hesitate to call it lapping, I used 800 grade wet and dry, possibly even 1000.  Some will probably say not fine enough, but I found it wears in quite quickly from there.  I also tried Brasso on the face, assembled the spring to hold the faces together while I turned the engine by hand.  An electric drill might have been better for this.  Not sure whether brasso is course or fine compared with the wet and dry.  I only had a machined wooden block with a hole for the pin to back the abrasive, and punched a hole on the paper so it would lie flat.  With that stand, you might have to square off the end of a dowell in the lathe and drill it for a wood locating pin, and again punch a hole in the paper.  Obviously both surfaces have to be flat to seal.

As far as I remember you donít have a superheater so the boiler only produces saturated steam.  Then that long copper tube makes quite a nice condenser, so the engine is probably seeing very wet steam.  That may be increasing the dramatic effect of the leakage.  Perhaps it would be worth setting the engine on a block and trying a quite short pipe, insulated by wrapping with strips of rag.  Might help a little, though port face sealing is the key.  Then a little exhaust separator to reduce the water condensing everywhere.

Looking forward to seeing the next build.  I also tried a double acting one before I started on the slide valve ones.

MJM460

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 20, 2019, 01:12:25 AM
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827326.jpg)

 8)
Great shot! 
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 20, 2019, 06:59:35 AM
Hi Gary, great to see it running on steam with your boiler.  Certainly appropriate to be basking in the glory of that first run.

I believe it will already be worthwhile taking off the nut and spring to remove the cylinder and closely inspect the port face, I think you will already be able to see if the wear pattern is even around the ports or not.  I have found that each of my oscillating engines benefited from some extra work on the port faces of both the cylinder and the standard.  I hesitate to call it lapping, I used 800 grade wet and dry, possibly even 1000.  Some will probably say not fine enough, but I found it wears in quite quickly from there.  I also tried Brasso on the face, assembled the spring to hold the faces together while I turned the engine by hand.  An electric drill might have been better for this.  Not sure whether brasso is course or fine compared with the wet and dry.  I only had a machined wooden block with a hole for the pin to back the abrasive, and punched a hole on the paper so it would lie flat.  With that stand, you might have to square off the end of a dowell in the lathe and drill it for a wood locating pin, and again punch a hole in the paper.  Obviously both surfaces have to be flat to seal.

As far as I remember you donít have a superheater so the boiler only produces saturated steam.  Then that long copper tube makes quite a nice condenser, so the engine is probably seeing very wet steam.  That may be increasing the dramatic effect of the leakage.  Perhaps it would be worth setting the engine on a block and trying a quite short pipe, insulated by wrapping with strips of rag.  Might help a little, though port face sealing is the key.  Then a little exhaust separator to reduce the water condensing everywhere.

Looking forward to seeing the next build.  I also tried a double acting one before I started on the slide valve ones.

MJM460

Thanks MJM. I'm working for the next two days but will look at the port faces at the weekend. I have a tube of 'Autosol'. Don't know if you have that brand in Australia or not, but I'd say it's a bit coarser than brasso and comes in the form of a cream, so it may do the trick. I think that maybe running the faces together with a drill and abrasive between them could be better than trying to isolate high spots to work on (which is a bit like shortening the legs of a table).

Regarding the piping - the long pipe was only provisional to try it out, but yes, I hadn't considered it's acting as a condenser. Also, I discovered last night that I hadn't soldered one of the nipples on to it properly so it was leaking!  You can probably see it in the video, at the engine end of the tube. So I might as well shorten the tube when I redo it. As for a condenser, that's something I'd like to do in due course (in the pipeline, so to speak   :) )

@ Chris - thanks!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: MJM460 on March 20, 2019, 10:12:03 AM
Hi Gary, the main problem with any cream, brasso or other with the engine assembled is that it might get in around the piston, I try to use the brasso (or any other brand) with the parts separate so I can clean them well before reassembling.  Now I think a bit more about it, that is why I turned the cylinder by hand rather than with the piston in place using the drill.  But it was slow, however the drill was a thought bubble that should have been pricked with a pin.  It might be easier if you can remove those screws holding the brass port face in place so the standard can be moved around on abrasive paper on a flat surface.  Because my stand was made of brass, it had a flat surface, which made it easier to ensure the abrasive was flat.

I should have been clearer about the condenser.  It takes a lot of area to completely condense the steam used by the engine, but that long tube will ensure that the engine sees very wet steam.  A shorter one will help, especially with a bit of insulation.

 After the engine, I find a simple separator collects the small amount of water that has condensed, while the remaining exhaust seems to spread out in the atmosphere as higher humidity, and does not create as much mess.  Just a simple tank with a tangential inlet and the outlet on the centre line so any water droplets tend to get separated by the tangential velocity and the change of direction to the final outlet.  It works better than intuition would tend to suggest.  And relatively simple to make as it does not see any pressure.  I have attached a picture of two that I have made.  The vertical one is more effective, the horizontal one needs a bit larger diameter for the horizontal section.

Once you have the engine running with the boiler, it is quite satisfying to complete these small steam plants.  Now I need to follow the lead from others and include a feed pump and feed water tank.

MJM460

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 20, 2019, 10:10:31 PM
Thanks MJM460.

What you say about Brasso etc and the risks to the piston and bore makes a lot of sense, so I'll avoid that.

I could remove the screws but one of them is JB Welded in due to a booboo I made so I'd have to take the head off and redrill, so I'll look at the port faces and lap any obvious high spots then let it wear for a while and see how it goes before I look at other options.

On condensers and steam separators, yes, it will be fun to explore these avenues in due course. Relatively low stress compared to engines, I suspect.

 :ThumbsUp:

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 22, 2019, 03:27:20 PM
Disaster! Catastrophe!! Apocalypse!!! Cataclysm!!!!

Well, I exaggerate. Pest, nuisance...

No. Actually, opportunity for learning and an improved engine.   :-)

I was running it today, and the JB Weld repair failed. The cylinder came off the pivot, leaving a jet of steam shooting out of the port into thin air. I know JB Weld is good stuff; I just think that in this instance it didn't have much of a platform to adhere to:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827505.jpg)

My solution will be to lightly skim the port face of the cylinder with an endmill, then solder on a piece of flat brass bar to create a block on the back of the cylinder into which a new port and pivot hole can be drilled. A new pivot will be made. The crank pin is plenty long enough to accommodate this. Indeed, it seems to me that the thin cylinder wall left after the flat is milled is the weakest point in Steve's design (which otherwise I like) as it leaves little room for the threaded end of the pivot. In fact I had already planned to solder on a block as above when I build my next (x2 scale) version of this engine, so this will be good practice.

It will also give me a second chance to add Tug's suggested composite pivot and Peter's suggested recess.

I take it soft solder will be ok for this job?
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Ramon on March 22, 2019, 04:04:29 PM
Commiserations Gary - sorry to hear that the JB wasn't enough to hold but as it appears that it was just a small fillet around the pin it's not surprising given the movement involved.

Your thoughts on soldering a plate to increase the thickness are on the right track - I had thought you were going to do that originally for as you say once the cylinder is milled to give a flat it leaves very little left in which to drill and tap a hole of decent depth to hold the pin.

FWIW - some time back I rebuilt a Blackgates Vee twin Oscillator and had to make new cylinders. I did not post on here but on a model boat forum. (That was where the image of the pin previously posted here emanated from) Given what's occurred it may be worth your time to take a quick run through before setting out again ? Anyway it's here if you think so https://www.modelboatmayhem.co.uk/forum/index.php/topic,53472.0.html (https://www.modelboatmayhem.co.uk/forum/index.php/topic,53472.0.html)

Soft solder will be OK to hold a plate on but if you do be aware that you will not be able to silver solder it after unless all traces of solder have been removed (usually re-machining is required - see the thread mentioned)

A slight set back but one which I'm sure you will soon overcome - good luck :ThumbsUp:

Regards - Tug
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 22, 2019, 04:12:28 PM
Thank you Tug.

Yes, in the design there is no plate but I think one will effectively be an upgrade to take forward into future projects.

I'm aware of the incompatibility between soft and silver solders but I don't think I'll need to use silver solder on the cylinder anyway so it should be ok.

I will read your v-twin thread with interest at some point over the weekend.

All the Best, and have a great weekend.

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 22, 2019, 05:04:41 PM
Sorry to hear it failed on you but I guess it is proving to be a good model to learn on  :(

It's a pain to have to modify it but it sounds like what you are wanting to do will improve things. Once it is up and running again I'd experiment with different springs, I'm not saying the one in your photo is necessarily too strong but it looks a bit rough and ready and I think the look of the engine could benefit from something a little more delicate.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 22, 2019, 05:10:14 PM
Bummer on the broken joint, but your solution sounds like a good plan. If you drilled/threaded the new block for the pivot before soldering on, you could through-thread it?
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on March 22, 2019, 11:21:52 PM
Hang in there Gary. You will overcome this I am sure.

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Kim on March 23, 2019, 04:50:16 AM
Sorry about the mishap.  It's all a part of learning though, isn't it?  And that's what makes this hobby fun!

Kim

You can rebuild it...  make it better than it was before... faster... stronger... 
(that's my reference to the Six Million Dollar Man :))
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 23, 2019, 09:48:20 AM
Sorry about the mishap.  It's all a part of learning though, isn't it?  And that's what makes this hobby fun!

Kim

You can rebuild it...  make it better than it was before... faster... stronger... 
(that's my reference to the Six Million Dollar Man :))

Gentlemen. I shall rebuild it.    :)

Agreed Kim - that's the way to look at it. A learning experience, and it wouldn't be fun if it was all easy.

@ Chris - sorry, I'm not sure what you mean. Any chance you could say a bit more?

@ Peter - I never gave the look of the spring much thought - just went out to local shops and bought a few different springs, tried them, and that one seemed to be the best one. Will keep my eyes open for one that looks better though.

@ Bill - yes indeed. I'm happy enough as the engine should be the better for it.

Thanks for all your feeedback guys  :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: MJM460 on March 23, 2019, 10:21:58 AM
Hi Gary,

Most unfortunate that, but the breakage shows the weakest point.  And perhaps you will be able to work out how to make it stronger another time by looking carefully at the break line.  Looking at the photo, I think the epoxy does not appear to have taken over the whole available contact area, I wonder if there was a little oil left from when it was running.  But soldering is probably better in the long run than epoxy, however good the epoxy.  And making that section thicker on future engine will make anchoring that pin a little easier.  I  have found it the trickiest bit of each of the oscillating engines I have made.

Just another hurdle, I am sure you will overcome it.

MJM460

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 23, 2019, 10:50:22 AM
Hi MJM -

I only epoxied it because I accidentally stripped the thread in the hole in the cylinder that the pin was to be screwed into. In this engine the design issue is that because of the flat milled on the port side of the cylinder there is not much thickness so the hole is of necessity very shallow. I think that Steve, the designer, made it that way to keep the making of the cylinder as simple as possible for beginners. I'm going to rectify that by soldering a brass plate on to allow a deeper hole, redrill the port and the pivot pin hole and tap the latter for a composite pivot of the kind proposed by Ramon on page two of this thread. I reckon that will give me a better engine than it would have been if I hadn't stripped that thread in the first place   :)

Cheers  :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 24, 2019, 10:35:06 PM

 Given what's occurred it may be worth your time to take a quick run through before setting out again ? Anyway it's here if you think so https://www.modelboatmayhem.co.uk/forum/index.php/topic,53472.0.html (https://www.modelboatmayhem.co.uk/forum/index.php/topic,53472.0.html)

Regards - Tug
Very interesting and informative thread that, Ramon.

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Ramon on March 24, 2019, 10:41:15 PM
Hi Gary

Glad that was worth a look - at least it may give you an idea or too but bear in mind there's always more than one way to skin a cat  ;)

Tug
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 24, 2019, 10:44:14 PM
Yes indeed!

 :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 26, 2019, 12:04:33 AM
I'm still waiting for the arrival of the flat brass bar from which I'm going to make the plate to attach to the cylinder barrel, so I went out today and picked up some bits and pieces for soft soldering. Tinning the components then joining them was suggested to me as an appropriate way to proceed, so tonight I had a practice on some bits of scrap brass:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827718.jpg)

Not much of a photo, I know, but it was that kind of a session...

The tinning and joining procedure was trickier than I expected but I began to get the hang of it with the help of a combination of advice and reading. Wiping the tinned surfaces with a damp sponge while the solder was still liquid worked well, leaving a uniform and very thin layer of solder on the surfaces. The parts then went back in the pickle for half an hour before joining. I tried a couple of different ways of positioning the work for heating, settling finally on a G clamp (holding the parts together, but not too tightly, with the faces for soldering held level), and the clamp in turn held in the vice. Initially they didn't seem to want to solder together, which I think was the result of not enough heat. I overcame that by working in the dark so I could see what was going on, using the Sievert torch to bring the parts to a dull red glow before quenching them in the pickle.

Now, at the end of the evening, I feel *fairly* confident that I'll be able to join the plate to the cylinder by tinning, and hopefully the brass flat bar will arrive tomorrow.

Flippin' heck, I didn't know how much time and work that stripped thread in the pivot hole was going to cause! All good experience though...

I'd welcome any comments you may have about the way I approached this. If I'm doing anything silly I'd rather know about it before I ruin the cylinder!

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 26, 2019, 12:13:26 AM
Good experiment! You don't need to quench it, just letting it cool works too. On thinparts quenching could distort it slightly.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 26, 2019, 12:23:44 AM
Ah, ok Chris. Thanks for that.

I decided to quench the parts to try to thermally shock the flux residue etc off them.

Will heed your advice when it comes to the real thing. Don't want any distortion, especially as it's the cylinder...
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 26, 2019, 12:42:13 AM
(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827734.jpg)

Antidote to photo three posts above    :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: 10KPete on March 26, 2019, 02:18:12 AM
Something everyone needs to know about soft soldering brass/bronze is that a strong acid flux must be used for the first wetting of the brass. Unless that 'layer' is removed, follow on soldering is done with mild (rosin) fluxes to reduce coloring and ease clean-up.

I've had 'opportunities' to test that requirement over the years and will say that while one may get away without acid once in a while, defective joints will result way more often. It's not worth the pain of a re-do for me to 'risk' it.

My two coins.

 :cheers:

Pete
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Jasonb on March 26, 2019, 07:10:29 AM
Your G-clamp will be sucking all the heat away from the parts, if you do need to hold them in place then a thin third hand that has minimal contact is the way to go.

As soft solder flux stays soft you don't need to "shock" it off that is a method that can be used for silver solder flux which sets glass hard, should also not really need to pickle as there will be minimal discolouration (when you can heat properly) and the flux will just was off with warm soapy water and an old toothbrush. Then quick rub with a grey Scotchbrite pad.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 26, 2019, 07:35:39 AM
Thanks guys. Noted.

@ Pete - will check the flux I bought yesterday and buy some strong acid today if it doesn't fit the bill.

@ Jason - I bought some soft iron wire yesterday. Might try that.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Ramon on March 26, 2019, 09:48:56 AM
Hi Gary,

I've not heard what Pete suggests regarding an acid based flux but don't dispute his advice. I have used bakers fluid before which is acid based but usually use Fluxite and smear the faces to be tinned liberally with it before heating. The faces should be nice and clean preferably straight from a rub across some wet and dry paper (400-600 grit). Heat until the solder flows then wipe off across the face with a piece of folded kitchen roll paper with a smear of flux on it. Coat the faces with flux again before bringing them together for soldering

Jason is right about the clamp taking the heat away - there is also absolutely no need to get the parts to a dull red as you describe to make the joint - just heat until you see the solder flow.

I use a bent piece of piano wire to act as a clamp which keeps the heat sink effect to a minimum - might be worth a try?  Something like this.
(https://lh3.googleusercontent.com/ztiDwopRQpiZdOcaP1gYgDNGwviJOCEM-zW2LyUEpFjiiiYwR5lWVbZOe-7Y9tIBf3-aucs_LsUrFAfHL3bw2ADLa8yvXoAQRjVHdHlIn9OsPkf2B1F-wK-xCQGzsf3qYtR2tJfq6a-yTndqCx4rwGCXv-CmC_l5C-yvU5C1VR__VIxTt4G35J07Mq8oBvagV0Lz2k8N0JqdNgF6Mp7H7z5I28R00gmrcwTJBrDaywd9pU31tJeDHXturRDzky1PT5lWIipy8Z2XGRHhD4pJvOyrjbcdDbsuzBSNEHZ4IdfjyVHmC_kmK2YosbW_cnZSQe2AT5fSbw0Z3cpf1UpMrGFOxmjjXu6c1QpU5wkxdfdwqWgi4L6wJlTV6G-Puxh0rWp6RoSGhy1ocxEMcGsBARWtcdY8jeoW820QRUz0uKXO_Y-MErK0hxCuPyqHNd_vr6XYuPUDaIpU5RnlekW9Ukx-j31SmQKdcoiOwGM59mxr6imC773QbCvWCuDufGo0MtwVsKWPKpl_WSX6fpsOyH3jTjT4uuhGjUGxnjUDeVDnPwWpTvaPaFvIgcydo_mxFEULgV-RWCMD3ciSLik6NbtFU_bb0_qWhvQfeRjRI4iwN-76lL8E3yn_KHUAZAtxThcz2zjItzwourUZAQ6heJlNWsH_2H0=w1218-h913-no)

Faces should be as flat as possible after tinning so if you have any small raised areas of solder either reheat and wipe off again or take off with a few strokes of a file. Reason for that is, that if the faces are not in flat contact as the solder melts, the piano wire clamp can induce an out of line movement as the faces close together. It might be a good idea in your case to have a small locating pin in a couple of places to prevent that.

I usually use a solvent such as acetone or cellulose thinner to clean the flux residue away.

Hope this helps some too - Tug
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 26, 2019, 11:00:26 AM
Tug -

thanks for all your good advice. I have the two fluxes shown for soft soldering:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827743.jpg)

I used the LA-CO last night. It's a thick paste. It seemed to be fine but Pete's post had me wondering so today I went out in search of a strong acid-based flux. I'm not sure whether the Baker's No 3 fluid fits the bill or not, but I see you have used it and will know that it's zinc chloride based.

Any thoughts from your good self or others on the relative merits of these two will be much appreciated. Until I hear anything, though, I'll test out the Baker's on some scrap brass.

Will bear in mind your other suggestions. The piano  wire seems like a 'sound' idea (sorry...) and I'll look at something equivalent after getting rid of the clamp and not looking for the material to glow dull red...
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Jasonb on March 26, 2019, 12:15:23 PM
I tend to use the paste even though I have Bakers Fluid on the shelf.

One other thing to bear in mind is when you are wiping the joint don't use anything with manmade fibres as they can melt, if using a sponge it should be natural. A cotton rag or paper is best. Same if applying flux to a hot surface with a brush - natural hair is best.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 26, 2019, 01:03:23 PM
Jason -

I used the small spare sponge that came with a soldering iron. Natural, I guess.

Will try the paper next, though it will just be to practice on scrap as the post has been and no brass bar today...

Cheers.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Ramon on March 26, 2019, 01:13:51 PM
Hi Gary,

Bakers fluid is a good flux but is very corrosive if traces of it are left. Folded paper as suggested is fine if fluxed but it will still scorch if contact is near static - unlike a piece of sponge though it's quickly replaceable.

If all the surfaces are clean and well fluxed it's all about getting the right amount of heat - as you've found any heat sink source can be a big hindrance in that direction. A gently applied heat to bring the parts up to temp and you will soon see the solder flow - that's the time to stop. Don't quench it but let it cool naturally - if you use Bakers then wash it thoroughly like Jason suggests.

Tug
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: 10KPete on March 26, 2019, 04:10:34 PM
That Bakers Fluid sounds like the 'right stuff'! I like to tin with the acid then clean up. That almost eliminates any corrosive residue and makes finish job much cleaner. And as Tug said, everything should be very clean before heating.

Cheers!

Pete
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 26, 2019, 04:46:35 PM
The piano wire is a great idea Tug, I'll remember that for next time I need to do a similar job.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 26, 2019, 06:05:55 PM
I am a little confused, are you using low or high temp solder?
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Ramon on March 26, 2019, 06:51:56 PM
Hi Peter - it works well but make sure you have the prong points as in line as you can get them - the spring end shape isn't that important but if they aren't inline it can induce a sliding/twisting motion to the two parts as the solder melts.

Chris - This is soft soldering but I think Gary got a bit carried away with the heat last night  :)

Regards - Tug
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 26, 2019, 07:07:05 PM
Thanks Tug. I guess and old wire coat hanger would do for some jobs.



Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 26, 2019, 07:16:17 PM
Hi Peter - it works well but make sure you have the prong points as in line as you can get them - the spring end shape isn't that important but if they aren't inline it can induce a sliding/twisting motion to the two parts as the solder melts.

Chris - This is soft soldering but I think Gary got a bit carried away with the heat last night  :)

Regards - Tug
Okay - in the earlier post when he mentioned getting the parts red hot, I assumed it was hi temp silver solder. That is WAY too hot for soft soldering!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 26, 2019, 11:15:19 PM
Okay - in the earlier post when he mentioned getting the parts red hot, I assumed it was hi temp silver solder. That is WAY too hot for soft soldering!

Yes, indeed it is. And I'm ashamed to admit that I did it again today, and with the cylinder (!) which led to all sorts of complications.  It started off ok, tinning the parts with Baker's fluid:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827803.jpg)

Suffice to say that my first attempt came apart due to slippage when I tried to join them (using no pins or piano wire, mistakenly thinking that gravity would do the job as the parts are quite chunky), and I lightly clamped (yes, clamped!)   :facepalm: and overheated my second attempt for fear of it coming apart again. The join seems solid, but the cylinder distorted and went somewhat out of round to the point that the piston wouldn't fit into it   :( . I think this was due to a combination of excessive heating and the pressure from the clamp, which was not huge but big enough to do damage. Why did I clamp it when I had been advised not to? Well, I didn't feel that in my particular case it was acting as a heat sink as my test pieces from yesterday are rock solid. What I didn't take into account was the fact that I was blasting enough heat into the system from a powerful torch to allow the metal to distort even while the clamp and vice pulled the heat away. Never again, I promise.

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827802.jpg)

I tried to rectify this by using the 'flex-hones', which resulted in the bore being too big for the piston! Thinking that I had lost it and that I would have to make a new cylinder, i.e. nothing to lose,  I decided to try cutting a groove in the piston...

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827801.jpg)

... and adding an o-ring...

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/827800.jpg)

... and to my surprise it's a snug fit and pulls a nice vacuum.

This is just a black rubber o-ring, (from a box by Rolson, size R-04) and I believe that it's not the right kind, but I guess I could change it or use some graphite yarn. However, I'm wondering if I really have managed to salvage the result of a sloppy day's work or if that out-of-round bore will come back to haunt me. If it does, I'll just have to bite the bullet, remake the cylinder and try to learn from it.

Meanwhile, I have been using my Sievert torch for soft soldering. I'm thinking that maybe that's part of the problem. Should I be using a smaller DIY blowtorch instead?

Amazing that one stripped thread can send one on such a long and tortuous journey. And that everything in this pursuit impacts on everything else. And that a single acting oscillator is an easy build yet I'm having plenty of trouble with it. And that I thought soft soldering would be easy, yet I'm having more trouble with it than I have had with silver solder. And that even today, having been given lots of good advice, I was selective about what I followed, thinking it didn't all apply to my particular circumstances...

Sorry guys. Thinking this engine was finished and then having to go back and redo all this has led me into rushing things. Never a good way to go. I will persevere, and slow down...

I'll be making two engines of the same type, but twice the size, when I eventually get this one done. At that point I will follow Tug's suggestion of using pins to stop movement when soldering (though I still have to learn how to do that).

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 27, 2019, 01:03:05 AM
Be great if the o ring salvages it. As for the sievert being too much, all depends which tip is on it, on the interchangeable ones you can go from a fine pencil flame to a boiler heating inferno.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 27, 2019, 06:54:25 AM
Thanks Chris.
It will be great if it does. If it doesn't, I'll have to make a new cylinder, in which case I'd be inclined to drill and ream the bore after I solder the plate on.
I'll also investigate other tips for the Sievert as I only have the 'boiler heating inferno' that came with it.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Jasonb on March 27, 2019, 07:09:46 AM
A flex hone will do just that and flex to the shape of the cylinder so you won't really make it round with one of those.

The O ring is likely taking up the difference in shape so you may get away with swapping it for a silicon one but it may well wear on the tight spots and become loose over time.

Your existing torch will be OK just don't get carried away with it, most soft solders will melt around 200deg C which is only oven temp and you don't see your dishes or shelves getting red hot. Also don't be in a rush to move the part once soldered as the solder will form a "dry" joint if disturbed while still semi molten. I would not change my burner for a part like this or even smaller items. You can always turn the regulator down on the cylinder which will stop you overdoing it with teh trigger or handle valve.

last thing is that first photo meant to show the tinned surface?
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 27, 2019, 07:21:07 AM
Thanks Jason.

Will keep in mind your points about the torch and regulator.

In your view, how would graphite yarn compare to a silicone o-ring in this case?

Yes, the first photo is meant to show the tinned surfaces. The indentation in the centre of the cylinder is where the solder has flowed into the original pivot hole with its stripped thread but not completely filled it.

Am I picking up that my tinning isn't what it should be....?
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Jasonb on March 27, 2019, 07:41:27 AM
I think an o ring will take up any deviations better than the yarn.

It's a trick of the photo or my eyes, when I just opened this thread again to see your message the surfaces looked quite grey and well tinned a few seconds later they looked more like bare brass  :headscratch:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 27, 2019, 07:45:15 AM
Yes, they were definitely grey with solder; no brass visible. Probably the one thing I got right yesterday   :)

I'll order some o-rings and some yarn anyway, to try both. Won't break the bank...

Cheers.

 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on March 27, 2019, 08:35:22 AM
I'm not entirely convinced that adding an O ring is the way forward, it seems to me that it could add extra friction that could be counterproductive in a single acting engine. As the engine is only under power on the downward stroke surely any benefit is lost fighting friction on the return stoke? I accept that the engine will run but my guess is you will lose power and find it may labour a bit.

It wont do any harm to try it but I'm inclined to think making a new piston is the way forward now  :(

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Jasonb on March 27, 2019, 09:19:56 AM
Given that the bore is probably still out of round but just bigger I can't see the point in making a piston to fit that. Either bore out the cyl to a true round and make a new piston to fit or make a new one piece cylinder bored to fit the existing piston.

Yes any seal will add stiction.

Easy option is to try it with ring/yard and see how it goes.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Ramon on March 27, 2019, 10:17:32 AM
Commiserations on this latest set back Gary but you have learnt quite a bit I would think ::) I remember things like this going wrong in my early days only too well. I was once told "You need to slow down in order to speed up" Couldn't see the logic in that at first but once the penny dropped things began to happen in a much more satisfying manner.

Given all that's gone wrong I would say you are now 'chasing your tail'. Things do sometimes go wrong and attempts to put them right can quickly lead you down a path not envisaged at the outset.  Maybe time to take a step back and consider starting over again on a completely new cylinder learning from all that's gone awry so far. Whatever way you go about any repair on this one it's just that now - a compromise - fixing something that's gone wrong, gone wrong, gone wrong, so to speak. There comes a point when it's simply best to start again as whatever you do will be trying to overcome previous problems and in all probability inducing new ones. Peters point about friction is a perfect example.

I would think that given your highly commendable approach to sorting things you can safely say you've given it a good shot but move forwards and start afresh on new parts. Hope you'll take this as well meant advice :)

Soldering - any form of 'extra metal' will act as a heat sink so you need to keep things in contact with as little as possible. A little brass rivet or two just acting as locating dowels would hold your plate in situ. For soft soldering I use a hand held gas torch if overall heat is required - set to give a soft flame not a roar. Heat the parts slowly - watch for the flux to melt and run and then touch the solder on. The part should be just hot enough for the solder to melt and sit there in a puddle - a quick wipe with that fluxed paper will quickly smear the solder evenly over the area - just keep the heat gently applied to keep the solder in a fluid state until the solder is well spread over the face then leave to cool naturally. Treat any high points as mentioned before and flux both faces before bringing together. You have found another potential for disaster in your attempts - that of brass being easily distorted by the slightest pressure once heated to around red heat. That likelihood is definitely something to be aware of when silver soldering but should not be of any concern when soft soldering as the temperature should be nowhere near.

You can ascertain what level of temp needed by taking a piece of scrap brass, clean the face and flux it then support it across your hearth bricks with minimal contact so that you can heat from underneath. Cut a nib of solder wire and lay it on the face then apply the heat gently from below - not directly on the face. As the metal increases in temperature you will soon see the point when the metal temp induces the solder to melt - that will give you a good idea of just how little heat - relative to silver soldering - is required.

Whatever way you go Gary - best of luck - hope you will not see this as anything other than what it is  :)

Regards - Tug

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 27, 2019, 11:10:50 AM
Tug, great description on the soldering.  :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on March 27, 2019, 11:58:05 AM
Gary, here is a shot of the different torches that have accumulated in my shop over the years. The first I picked up (and still use a lot) is the little black one with the red knob - refillable butane, use it a lot for both soft soldering and for silver soldering small parts. It would be plenty for the size of your cylinder for soft or hard soldering.
(https://i.postimg.cc/2SMrkbYN/IMG-4774.jpg)
The rest I only use for high temperature silver soldering. Bigger yellow one on right is a MAPP gas torch, good for slightly bigger parts. The Sievert system, fed from a 20 pound propane grill tank with Seivert regulator, on the left, with the box o tips, is good for everything from small frames up to large boilers.
The flux you use varies with the solder - low temp solder only works in the temp range for low temp/soft solders. The high temp flux for hard soldering only works in the 1100-1400F range. Below that it does nothing, above it burns off and does nothing.
 :cheers:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 27, 2019, 12:31:51 PM
Given that the bore is probably still out of round but just bigger I can't see the point in making a piston to fit that. Either bore out the cyl to a true round and make a new piston to fit or make a new one piece cylinder bored to fit the existing piston.

Yes any seal will add stiction.

Easy option is to try it with ring/yard and see how it goes.

Yes... @Jason and Peter: my first step will be to try out the existing cylinder with a silicone ring and with graphite yarn, to see how it goes (rings and yarn are both ordered). There's very little to lose in trying it. If it doesn't work, or works but in too compromised a way, then I'll have to make a new cylinder as it's the cylinder that's the problem. If I do this, I'll either revert to the original design and thread the pivot hole with a square-ground tap to make sure it bottoms properly and doesn't strip again, or I'll solder on a plate before boring the cylinder, not after.

I can't rebore the existing cylinder as the screw holes for the cap are too close to the bore, and quite deep so further boring would most probably break into them.

Making a new cylinder would be quite easy; making it to fit the piston (rather than the other way round) probably less so, but clearly it's doable and will be good practice.

@ Tug - thank you for both your detailed advice on soldering and your sharing your wisdom on the philosophy that underpins this work (which is very important).

@ Chris - I have a couple of other torches too - will have a think about which ones best suit different applications. Cheers.

Thanks for your support, all. Just amazing!   :ThumbsUp:

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on March 27, 2019, 01:06:27 PM
Gary, thanks to you for posting all of these trials and tribulations and thanks to others for providing suggestions as well. I know I can and need to learn more about soldering both soft and hard so all of this is really helpful!!

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on March 27, 2019, 10:23:24 PM
Bill -

I'm glad that some good has come out of this for you as well as for me.

One thing I notice with building engines is that mistakes can be very quickly reframed as learning opportunities.

BTW I will try the existing setup with the silicone ring and graphite yarn to see how it works, but am more inclined now just to remake the cylinder.

This small wobbler has become something of a marathon project, but it takes the time it takes, and the money spent on materials isn't really spent on one small engine, but on a lot of learning.

Cheers,

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on April 01, 2019, 10:05:43 AM
Following my ludicrous foray into soft soldering land, I trial fitted the modified cylinder to the engine, only to find that the excessive heat had mangled it beyond recognition and rendered it fit only for the brass recycling bin. So... I made another cylinder. This time I was able to fit the composite crank pin, as suggested by Ramon, and mill a recess in the middle section to allow better contact between the port face and the wear plate, as suggested by Peter. Also at Peter's suggestion I changed the position of the bore, shifting it away from the port face in order to leave more metal to take a drilled and tapped holed for the pivot. There was only room to shift the bore by 1 millimetre but as we all  know that can make a big difference. In order to do this I had to drill and ream the bore in the mill as the position specified in the plans arises from the offset caused by the port face when the part is held in a 3-jaw chuck. I used the mill because I don't yet have a 4-jaw. With hindsight, shifting the bore out like this seems an obvious solution, but it would never have occurred to me. Maybe it will come with experience! Meanwhile, thanks Peter and Tug. I then took extra care with drilling and tapping the pivot hole, drilling first with a 3.3 mm tapping drill, then squaring off the bottom of the hole with the same drill with the point ground off, then using the usual three M4 taps before bottoming the thread with a plug tap ground square at the end. This all worked well. Cheers to Jason and a couple of others for educating me about grinding the ends off taps.

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/828074.jpg) 

The video below shows the engine (finished, apart from a shine up and the walnut base) running on the boiler driven by a pressurizing kerosene stove. The video is also relevant to my boiler thread so I'll post it there too:

http://www.youtube.com/watch?v=FN4fvsMWZL8

As for learning how to soft solder properly, well, that's another day's work.   ;) 
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: bent on April 01, 2019, 04:32:25 PM
Atta boy!  Looks like a runner, and you've fixed the leaks.  :cheers:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on April 01, 2019, 05:53:52 PM
Cheers Bent    :cheers:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Admiral_dk on April 01, 2019, 06:14:30 PM
Congratulations on your achievement - succes on all accounts in the end  :cheers:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on April 01, 2019, 06:55:16 PM
Thank you, Admiral_dk!

 :cheers:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on April 01, 2019, 07:25:22 PM
Great job on the engine, great learning experience! Have you decided what the next project will be yet?
 :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on April 01, 2019, 09:26:47 PM
Great job Gary, it looks like you have a great little runner there and with a homemade boiler powering it that's got to be something to be proud of  :)

I'm a big believer that when you deviate from the plans now and again you'll get setbacks but identifying what is wrong and how best to get around the problem is a great tutor. Full marks for sticking at it and adapting things along the way, ultimately you got a great little engine that's a bit out of the ordinary and at the same time learnt a bit along they way.

I reckon a Potty Mill engine has to be next on the 'to do'  :stir:

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on April 01, 2019, 09:59:07 PM
Very nice Gary. Perseverance wins in the end. Well done!!!

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on April 01, 2019, 10:07:44 PM
Thanks both  :-)

Yes, it's amazing what one learns from even a small project like this, and it's not too difficult to see the wrong turnings as opportunities to gain knowledge which can be used in the future.

Next project? Well, the Potty Mill is on my list, but I plan to make two more single acting oscillators next - twice the size of this one (24 mm bore), one single cylinder, one twin. Again, they will be built according to my own aesthetic (as will my version of the Potty Mill when I get round to it), and I plan to take the 'look' a bit further as I go along...

But before I do any of that I plan to get the boiler clad and properly set up and the different burners for it all looking good.

Cheers  :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on April 01, 2019, 10:08:31 PM
Very nice Gary. Perseverance wins in the end. Well done!!!

Bill

Thank you Bill.

 :)
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: MJM460 on April 01, 2019, 11:14:34 PM
Hi Gary, well done on getting it all running.  A great achievement and very satisfying after all the trials you have been through, but successfully conquered.  And you know a little more about what to look for in a design that might be more tricky to achieve.

Perhaps before another engine, the cladding as you say, a base board and tidy up the piping as a couple of suggestions.

But great to see it running.

MJM460

Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on April 02, 2019, 09:34:15 AM
Thank you MJM. Much appreciated. It's a learning curve indeed, and that's probably the most satisfying thing about it.

I agree - time to consolidate the plant a bit  before pushing ahead with the next engine!
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on April 09, 2019, 09:38:38 AM
Because I mentioned this somewhere above, and for the sake of completeness:

http://www.youtube.com/watch?v=biL2vJSFsms
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on April 30, 2019, 09:59:41 PM
Well, here is the finished engine mounted on its plinth:

(https://www.model-engineer.co.uk/sites/7/images/member_albums/173350/829997.jpg)

The walnut was given several coats of Danish oil. The plinth is really just for display purposes - when in use the engine will be taken off the plinth and its metal base fixed directly on to the base of the steam plant I am now starting to work on around the three inch boiler. I intend to sort out the plant before moving on to my next engine.

That pretty much wraps up this thread now. The development of the plant will be the subject of a new thread which I shall open soon.

Many thanks to all of you for encouraging, advising and supporting me in building my first engine.

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Gas_mantle on April 30, 2019, 10:40:41 PM
Looks great  :)

Well done on creating an attractive little engine at your first attempt.
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: crueby on April 30, 2019, 10:53:48 PM
Wonderful start to the hobby!    :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on April 30, 2019, 11:04:08 PM
Thanks both.

 :ThumbsUp: :ThumbsUp:
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Ye-Ole Steam Dude on April 30, 2019, 11:12:39 PM
Hello Gary,

Wonderful looking engine and very well displayed.  :ThumbsUp:

Have a great day,
Thomas
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: MJM460 on April 30, 2019, 11:13:43 PM
Looks great, Gary.  One to be proud of.

MJM460
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: Kim on May 01, 2019, 05:22:13 AM
Beautiful engine there, Gary, and the base shows it off quite well!
Kim
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on May 01, 2019, 07:01:42 AM
Thanks guys. Very kind of you.

gary
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: b.lindsey on May 01, 2019, 02:27:49 PM
The finished engine and its base look wonderful Gary. You certainly personalized this one in a very nice way!!

Bill
Title: Re: A Beginner's First Engine (Single-acting Oscillator)
Post by: gary.a.ayres on May 02, 2019, 06:49:43 AM
Thank you Bill.

gary