Author Topic: A Beginner's First Engine (Single-acting Oscillator)  (Read 894 times)

Offline gary.a.ayres

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #15 on: February 12, 2019, 12:03:09 AM »
Many thanks guys.

Your interest and support are greatly appreciated.

 :)

Offline gary.a.ayres

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #16 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!

Offline cnr6400

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #17 on: February 12, 2019, 02:31:11 AM »
Great progress Gary, well done!  :ThumbsUp: :popcorn:

Offline Ramon

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #18 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
« Last Edit: February 12, 2019, 08:53:55 AM by Ramon »
"I ain't here for the long time but I am here for a good time"
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Offline gary.a.ayres

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #19 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

Offline Gas_mantle

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #20 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.

Offline gary.a.ayres

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #21 on: February 12, 2019, 10:57:47 AM »
No problem Peter. Banana-shaped piston.

On the bushing - I agree   :)

Offline Ramon

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #22 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


Hope that's of use - Tug
"I ain't here for the long time but I am here for a good time"
(a very apt phrase - thanks to a well meaning MEM friend)

Offline Gas_mantle

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #23 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.

Offline Zephyrin

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #24 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.

Offline Jasonb

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #25 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

Offline gary.a.ayres

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #26 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

Offline gary.a.ayres

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #27 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)

Offline Gas_mantle

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #28 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


Offline gary.a.ayres

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Re: A Beginner's First Engine (Single-acting Oscillator)
« Reply #29 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