Author Topic: The Bolton No 5 Vertical Open Column Steam Engine  (Read 14677 times)

Offline MJM460

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #30 on: October 12, 2020, 12:02:55 PM »
Hi Ramon, thanks for looking in.  Please don’t hesitate to offer a few hints if I am doing anything wrong or if there are better techniques for me to try next time.

I wonder if annealing is one of those time-temperature processes, that can occur at higher temperatures over a short time, or lower temperature over a longer time.  Perhaps the observed reduction of the movement tendency is just an extreme of the time element at ambient temperature.  Perhaps the peeing on it made everyone avoid touching the casting until the event was forgotten, and that took long enough.  Slow might even be an advantage compared with quicker heating.  It would be interesting to know more about it.

Hi Gary, thanks for looking in.  I don’t think it’s a race, and besides you are well ahead on the cylinder.  I am just proceeding slowly, trying to set up each step so the cut or hole is in the right place.  It’s taking restraint, as it’s so tempting to start cutting.   So often I see a better way of ensuring the cut is in the right place only after I see that what I have done is not quite where I wanted. 

I think that your approach to balancing is probably just as effective as mine.

Hi Willy, thanks is for looking in.  Sitting the shaft on parallels as you have described is what I mean by a static balance.  I am interested to see what it shows, but I don’t think it’s worth finessing too much, as there is still the reciprocating mass of the piston and crosshead, which can’t be balanced that way.  But I need to machine the conrod before I can try it.  The best way to balance a reciprocating engine is to have two cylinders horizontally opposed, but there are still moments and secondary forces to contend with.    I have even seen compressors built with a forked big end, so the cylinders and conrods were truly in line to eliminate the torques about the vertical axis.

Today I decided the time has come to start the cylinder. 

The cylinder casting had the bore and one end face already machined.  That is a big help to a beginner.  The machined face had been done at the same setting so they were truly square.  So my first task was to machine the face for the top head.

I made a mandrel which was a quite tight fit on the cylinder bore.  With the cylinder pushed firmly on to the mandrel, I was able to machine the top flange face.  As the bottom head was finished, I had to decide how thick to leave the top flange.  Unfortunately the thickness of the casting did not allow the same thickness as the lower flange, so I just took a minimum skim to clean up the face. 

It ended up about 3 mm longer than the drawing, but the piston still has to be made, and there is also room to adjust the spigots on the top and bottom head.  If I had machined to the overall length, there would have been a very skinny top flange.  The end result looks ok, so time to push that mandrel out.  It was a bit tighter than it seemed when I pushed it in.  I wonder if aluminium was really the best choice for the mandrel material.

Next step was to clean up the port face.  I was a bit conflicted, as I wanted to mill the ports before I moved the cylinder after facing, but I wanted to cross drill for the exhaust outlet before I drilled the exhaust port.  Drilling the exhaust port won out as I suspect this sequence might be less likely to break a drill in the casting.  But until I faced the port face, I didn’t really know exactly where the face would end up to locate the port.

So I marked the exhaust outlet location, then set up the casting with the port face vertical, spot drilled for location, then drilled 3 mm right through.  My reasoning is that I am not sure which side I want the exhaust, so I made provision to use either side, and will make a plug for the other.  I spot faced the surface of the casting with a 10 mm end mill for the exhaust fitting to seat against, then drilled 5 mm x 7 mm deep for M6 and tapped for the fitting.  This leaves the section under the actual port 3 mm diameter.

I then turned the cylinder over and again set the port face vertical with the other side exhaust port upwards.  I adjusted the mill table so the 3 mm drill entered cleanly the hole already drilled.  I then spot faced the casting face, and drilled and tapped for the alternative exhaust outlet.

That was enough excitement for one day.  Time for a ginger beer, dinner and write my post.

Thanks to all for looking in.

MJM460

« Last Edit: October 12, 2020, 12:13:40 PM by MJM460 »
The more I learn, the more I find that I still have to learn!

Offline deltatango

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #31 on: October 12, 2020, 12:16:13 PM »
Hi MJM,
Great progress, and rapid progress too! As you said to Gary, none of this is meant to be a race but seeing someone else's good progress does focus the mind.

Regards, David
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Offline gary.a.ayres

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #32 on: October 12, 2020, 12:41:50 PM »
Hi MJM - it's definitely not a race! Heaven forbid...

I was just bantering.   ;)

We each have our own time to take and our own pace, and that's how it should be.

The wonders of pee: I was stung by some small jellyfish a few years ago while swimming, and a passer-by told my friend that if he peed on the stung areas it would neutralize the poison. Needless to say, I never got the chance to find out whether it would have worked or not. Perhaps he was saving it for some castings...

Nice to see that cylinder starting to take shape and come up shiny...

 :popcorn:

Offline MJM460

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #33 on: October 13, 2020, 11:34:14 AM »
Hi David, I am glad it looks like fast progress, it always seems slow compared with what some do on this forum.  But being under lockdown and getting a little done each day makes a big difference.  Strange, it does not seem like a lot of time available each day even in lockdown.  If we ever get it loosened up, I am sure that other things will suddenly crowd out any thoughts of shop time.

Hi Gary, banter is always welcome.

Today there seemed no alternative but to start on the steam ports.

The drawings say 3 mm for the exhaust port, and 1.5 mm for the two steam port.  I have a 2.5 mm milling cutter but have not used anything smaller.  I felt pretty nervous about using a 1.5 mm cutter.

In studying and getting familiar with the plans long before I made a start, I decided I could probably make it all work with 2 mm steam ports and could crib back some of the space by using 2.5 mm for the exhaust port, so I mail ordered two 2 mm end mills in preparation in the first days of the lockdown.  They duly arrived some time back.  They look fragile, glad I didn’t try for 1.5 mm.

So today, the big day.  I blued the port face with my marker pen, and scribed the lightest possible centre line, as it will later have to be polished off to make the valve seal.  I set the cylinder up again with the port face horizontal.  I located the centre of the exhaust port and set the end stops with feeler gauges. 

I first did the exhaust port with the 2.5 mm cutter.  It broke nicely through into the exhaust outlet I drilled yesterday.  And no breakages so far.  Basically I plunged, using the cutter like a drill, then moved over 0.25 mm and plunged again until I had traversed the whole port dimension.  Then I plunged and moved sideways to clean up the edges, but I am not sure that was necessary.

I then set up dial gauges to provide ARO (analogue read out) of the table movements, and moved to the centre of one of the steam ports.  Set up a 2 mm cutter and followed the same procedure for the first steam port, but 0.2 mm moved for each plunge.    Of course I had to adjust those end stops again for the smaller diameter cutter.  And then the same again for the second steam port.  Must have held my tongue right all the way through.

Finally, I took a light skim across the surface to remove that scribes mark.  It should polish well enough now.

Elated to have all three ports done, and the port face skimmed, I decided to call it a day.  A small step if measured in the swarf produced, but a giant leap forward in terms of building a working engine.

Thanks for looking in,

MJM460

« Last Edit: October 13, 2020, 11:44:18 AM by MJM460 »
The more I learn, the more I find that I still have to learn!

Offline gary.a.ayres

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #34 on: October 13, 2020, 12:47:35 PM »
Wow, yes - reading that I felt your tension and concentration...

1.5mm (or 2mm) endmills would frighten the life out of me, especially on a casting!

Congratulations on successfully taking this tricky step.

Offline Ramon Wilson

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #35 on: October 13, 2020, 02:08:27 PM »
........  Please don’t hesitate to offer a few hints if I am doing anything wrong or if there are better techniques for me to try next time.

I wonder if annealing is one of those time-temperature processes, that can occur at higher temperatures over a short time, or lower temperature over a longer time.  Perhaps the observed reduction of the movement tendency is just an extreme of the time element at ambient temperature.  Perhaps the peeing on it made everyone avoid touching the casting until the event was forgotten, and that took long enough.  Slow might even be an advantage compared with quicker heating.  It would be interesting to know more about it.


Hi MJM,

Looking at what's happening in your 'shid' I don't think you need any hints on this - all looking good so far :ThumbsUp: though the only thing I would say which is worth saying and something you are probably aware of is that for the best machining finish on bronze the tools have to be razor sharp and have never been used to cut steel beforehand. If so the material will tend to be 'pushed' rather than cut. A very noticeable difference on surface finish between the two.

There's no more to tell from this end - as said this could all have been myths but the practice was followed. As an apprentice welder I would often be given the job of welding up blow holes in bright shiny new castings - for some reason they nearly always appeared to be warp drums for the trawl winches. Ha I can remember the rods - Murex 'Fortrex'. These castings were never pre- heated but the areas excessively peened throughout the process (thats peened on not peed on ;D) with very sharp pointed chipping hammers made from old square files (Drawn and heat treated by the blacksmith 'Old Freddie Osborne'  they would always out last any commercial version)  The castings would then be left outside to the elements before final machining. The yard where I began my working life had produced their own steam engines (well before I started I should stress) everything on the ship save rope was made on the yard in those days. They were stll using rivets on the hulls and superstructures when I began (1960).  I expect there are one or too others on here who have similar memories  :old:
In this day and age though I can't imagine castings sitting around for too long to age - things have moved on a pace just a tad since then eh?

BTW as far as peeing on things are concerned it was a well known local fact that the town's deep sea fishermen recommended peeing over chapped hands as method of preventing it worsening - did it work? heaven knows but they thought it did  ;D and it was a done thing for apprentices to pee on the surrounding coals on the rivet heaters forge when the air was off and the fire low whilst he was at teabreak. Once the fire was revitalised the smell would soon have the guy cursing   :lolb:

Happy days indeed

Enjoy that machining - Ramon


"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 gary.a.ayres

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #36 on: October 13, 2020, 02:11:49 PM »
Fascinating bit of history there, Ramon!

 :)

Offline MJM460

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #37 on: October 14, 2020, 01:12:07 PM »
Hi Gary, It was certainly a sigh of relief when I completed the 2 mm ports.  Not as bad as I feared, but I will do a bit more at 2 mm before I try 1.5 or beyond.  And I still have one cutter unused.  I have labelled the boxes for future reference.  And I suspect that I need a higher spindle speed before I try slot cutting.  My mill only has 6 speeds, and the maximum is only 1600 rpm, way to slow for a 2 mm cutter.

Hi Ramon, thanks so much for the kind words.  When I look at your work, I have along way to go, but so long as I am going the right way about it, then I am learning, and I hope improving. 

I guess every factory has its favourite job for the apprentices.  But while I am sure those jobs were seen as boring, the practice seemed to produce very good results.  I sometimes wonder if the result could have been achieved with some more interesting assignments.  Still, those warp drum castings had to be repaired.

Riveted ship hulls?  They were probably the ones that stayed afloat as required when the liberty ships were sinking.  Or were the Liberty ships earlier again?  Interesting reminders of history.

Well, back in my garage, with the steam ports in the port face done, there was nowhere much to go but tackle the long angled passages to the cylinder ends.  Now I have the port face finish machined, I could measure up, and make an estimate of the required angle.  I hesitate to say accurate calculation, but it seemed good enough to ensure that the passages will intersect with the already machined ports.

I was also able to make an estimate of the passage length.  Eleven mm.  I wondered if the 2 mm cutter would plunge that deep.  Too deep for a sideways cut, but possibly a plunge.

The calculated angle was 12 degrees.  I have one of those tilting vices, the light one more like a drilling vice than the heavy milling tilting vices.  But it has been sufficiently rigid for light cuts and plunge milling on my previous engines, so I carefully set the angle, and set up the vice on the mill table nice and square.  Looking side on, it certainly looked about right.  I put the port face against the fixed jaw to get it all square, and used a wood pad between the casting and moving jaw in the hope it would deform a bit under the clamping pressure, and so distribute the force between the two flanges to some extent.

I started with a 3 mm cutter and milled a little flat at the edge of the bore to give a square face to start from.  And I widened the flat to the same width as the port face ports.  The design suggested drilling three holes 5/64” diameter, but I find it too easy for the drilled holes to drift into each other unless they are well separated.  I decided to try the 2 mm cutter, and if it would not reach I could try drilling out two or three holes for the last mm or so.   All much easier to see in the photo than to describe.

The first plunge did break through and also intersected quite accurately.  I think it was the depth of that flat cut at the end that was just enough.  So I followed the previous procedure of moving across 0.2 mm between each plunge.  I even moved across to make a final clean up of the passage sides, though not full depth.  Probably not necessary anyway, as the ribs from the plunge process are parallel to the steam flow, so probably make no difference in practice.  Not worth risking breaking a cutter to worry to much.

So with a lot of long breath holding and plunging with frequent chip clearing, the job was done.  I turned the casting end for end and completed the other end.  I did at least remember to photograph the first completed end, the other end is very similar as you would expect.

Only a few grams more swarf, but another great leap forward for the engine.  The entry into the cylinder is still not very deep, and will probably be blocked by the spigots on the heads.  I need to remember to machine a little notch in those spigots when I get to work on the two heads.

Time for another ginger beer.

That feels like a major milestone.  Machining of cylinder casting is just about complete.  I do have to drill and tap for head bolts, and bolts for the steam chest.  Yes, I know they should be studs, especially for the steam chest, but they are 2.5 mm.  I don’t have any 2.5 mm rod, but more importantly, my ER32 collets will not hold 2.5 mm diameter.  I have the 3 mm collet, and they are supposed to have a 1 mm range.  But I have found that while the bigger ones will squeeze in quite a bit, I am unable to tighten the little ones enough.   I am thinking I might need to go to an arbour and some ER 11 or even ER16 collets for smaller sizes, but I am not ready to make the outlay yet.  I could turn down some 3 mm rod and thread one end, then make a mandrel to hold the stud by the threaded end while I thread the other.  Does that sound like a plan?  Or is there a better way?  At least for the steam chest.

Thanks to everyone looking in,

MJM460

The more I learn, the more I find that I still have to learn!

Offline Bear

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #38 on: October 14, 2020, 04:04:22 PM »
Great work, MJM. For some reason, I missed the start of this thread; but, I guess it is better late than never. I will be following along on this interesting build thread.

Offline gary.a.ayres

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #39 on: October 14, 2020, 05:07:15 PM »
It never ceases to fascinate me that we spend so much of our spare time on tenterhooks and call it 'pleasure'.   :)

But it's these moments of success that make it so. Good work on these passages.

As you say, another step forward...

Offline crueby

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #40 on: October 14, 2020, 05:25:45 PM »
Nice progress!   :popcorn: :popcorn: :popcorn:

Offline MJM460

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #41 on: October 15, 2020, 10:45:32 AM »
Hi Bear, great to have you along.  I have also been following your build.  There have been so many comments on Elmers engines over the years that I am sure that I will have to try one soon.  So most interested in how yours goes.

Hi Gary, I think the pleasure comes with achievement when such a process is completed.  But not to be stressed during such critical operations could only mean one is not aware of what could go wrong.  The stress ensures concentration.  That’s my story anyway.  In reality, those ports on this engine do seem to have a bit more tolerance than some I have seen recommended as beginners engines, so they were not really too bad.  And only one size smaller in some of the critical dimensions than my previous engines, so an appropriate development step for me.

Hi Chris, thanks for looking in.  It must look like glacial progress when compared with what you achieve.

Today was a couple of more straightforward jobs. 

The steam chest had a reference face machined and the valve rod drilling and threads for the gland tapped all at one setting to ensure squareness.  I had to clean up the inside surfaces, and bring the side that goes against the cylinder to dimension so the valve rod is now at the right height.  The outside was very close to dimension, so I chose to wait until it was bolted in place with the cover to just clean up so all the surfaces matched.  That will come tomorrow.  Today  I marked out and drilled the four bolt holes, then spotted through those holes to the steam chest, and the other way to the cover. 

I set up the cylinder casting with the port face horizontal, but slightly above the jaws.  I was then able to use a clamp to hold the steam chest properly lined up while I spotted through.  Then I swung the chest out of the way while I drilled and tapped the holes in the cylinder.

Of course, that meant next I had to clean up the cover casting.  The outside face was machined so I had a reference surface, but I had to face the inside surface.  It was tricky setting up parallels to support the thin casting yet still have the face clear above the jaws for machining.  I couldn’t see how to clamp a component less than 5 mm thick direct onto the table.  I think Willy has one of those thin part vices, but he is a bit far away, and postage is so slow these days.

I vacillate between drilling the steam chest holes to size and spotting through with the drill before swapping to the tapping size drill, or drilling through the steam chest with the tapping size into the cylinder then return and open up the steam chest holes.  This time, I started with the 2.5 mm drill for the bolts.

I still managed to get the holes in the cover slightly off, I think I let something move at the critical moment, so had to elongate the holes slightly.  They are still well covered by the bolt heads, or nuts if make studs.  Still thinking about that one.

Tomorrow, I will bolt the steam chest on and face up the sides so they all mate nicely.

Thanks for looking in,

MJM460



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Offline deltatango

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #42 on: October 15, 2020, 12:14:56 PM »
Hi MJM,
Great progress!

You said "The stress ensures concentration" - one of my motivations for having the workshop projects while I was still working was to have an absorbing activity that forced work thoughts well into the background.

Seeing the steam passages come out in the right place is a good feeling, still remember that from building "Minnie" (maybe 30 years ago?).

For jobs like the steam chest cover I always drill tapping size first then open up to clearance size. If there was a DRO on the drill-mill (Sieg X3) then this would be less necessary.

David
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Offline Bear

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #43 on: October 15, 2020, 04:08:16 PM »
Hi Bear, great to have you along.  I have also been following your build.  There have been so many comments on Elmers engines over the years that I am sure that I will have to try one soon.  So most interested in how yours goes.
...

...

...

Of course, that meant next I had to clean up the cover casting.  The outside face was machined so I had a reference surface, but I had to face the inside surface.  It was tricky setting up parallels to support the thin casting yet still have the face clear above the jaws for machining.  I couldn’t see how to clamp a component less than 5 mm thick direct onto the table.  I think Willy has one of those thin part vices, but he is a bit far away, and postage is so slow these days.

...

...

...

...,

MJM460

Thanks, MJM. The quoted part above gave me an idea for where I am having difficulty squaring up the steam chest cover on mine. I have no vise or parallels of the correct size that will work on my Taig mill. Based on your reference to laying the part direct on the mill table, I think I may try to use a sacrificial aluminum plate, and mount the plate and the thin part to the table, and attempt to square it up that way (not sure if it will work; but may give it a try).

However, I saw a good YouTube video yesterday that would work, using three 123 blocks, if I had a larger mill vise, with the use of three 123 blocks. The video is from Joe Pieczynski. The portion that may be applicable starts at around the 16 minute mark. Did not know if appropriate to use a You Tube link here, but,it can be found by searching the above name un YouTube. The date of the video was yesterday. It is titled Machining a Model Steam Engine - Part 4 - Square Collets and Small Parts.

EDIT: I was out at the milling machine messing around with ways to tackle this. I see there are many ways to "skin a cat". I decided against mounting flat on the sacrificial aluminum. So, I will show what I did in my thread. I actually am trying something similar to the YouTube video; but, with parallels instead of the 123 blocks.
« Last Edit: October 15, 2020, 08:06:14 PM by Bear »

Offline gary.a.ayres

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #44 on: October 15, 2020, 11:40:01 PM »
not to be stressed during such critical operations could only mean one is not aware of what could go wrong.  The stress ensures concentration.


Agreed. We seem to have evolved that way.

I so recognize that slight misalignment when spotting through! Even with transfer punches and a determination to be accurate, easy for a slight error to creep in.

You got away with it though!

 

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