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Bolton Triple Expansion Engine “The End Test”

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Feb 28, 2026
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A short intro into this model of the triple expansion engine’s history,
Hello everyone.. first post Thumbsup
It was started in 1983 by Mr Mick Cook. Mick was a Toolmaker by trade and also a keen very talented model engineer from an early age. He has produced many many incredible builds over the years, from clocks to Traction engines to loco’s even a steam powered hydroplane all scratch built. He was the chief model maker at the Ford motor company Basildon plant for the retirement gifts, things like, working lathes in bottles to many different job related models! great job if you are a keen model maker !

I was fortunate to be Micks apprentice, And that’s something that stood me in good stead for the rest of my own engineering career.

Mick is now 91 years old and unfortunately has lost his sight and has had to give up his workshop activities.. very sad to see him giving away his lifetime collection of tools and equipment. And so this is how i came to be tasked with the ‘Apprentice end test’..!

One day while visiting him he said “I want you to have this” and uncovered the triple..!
As you can imagine I was a little surprised also also excited.. then came the BUT.. You have to finish it in the same way as it was started…!! So let me explaine…
Micks ethos regarding model making is simple to say but not so easy to undertake.
‘Detail’ when do you stop? - when you can’t see it. (That does not mean if it’s hidden it means when it’s so small you physically can’t see it! :-))
‘Making things look right’ - make it as the real thing would be manufactured not the simple route.

Thanks Mick…

So my workshop is well equipped I’m retired now and been a luthier for many years, and I build bespoke vinyl turntables tone arms. Platters and plinths all for those those black plastic discs that make the best music ever ! Being a youngster of 65, my imperial days are in the distant past. Fortunately DRO,s do both haha !

It’s taken me a few weeks to get back into the rhythm, but parts are starting to come off and they seem to fit okay.. purchasing silver soldering equipment and various materials to do this job has taken some time, but things are falling into place there to, so I would like to share the journey and also keep a log for Mick my Mentor !

Cheers

‘The apprentice’

Karl
 
So the first job was to sort through the parts and items given to me in a big box and tins. Drawings supplied are the revised version by J.P. Bertiant, (wow how anyone has ever made this engine using these dwg’s without extensive experience is quite amazing) No datum’s no tolerances and endless chain dims. And a few to many mistakes. But heyho all in the challenge. I have the complete ME walk through from the period which is quite detailed and the new book that’s just been published by E&J Winter for the Bolton No 9 triple expansion engine. This book is again a walk through but differs a little from the original build, im not following some of this books details as i think it deters from the spirit of ME. (Personal opinion)
So having collated materials tools etc. Time to get cracking Thumbsup
Looking at the build i decided to make the parts to get the engine in a running state. Mick had made all the valve gear but not assembled the IP valve. So i striped it back made a few mods. And basic timing set, the engine turned over by hand but with some tight spots. (Remember this had not move in nearly 40 years.
So having reasonable confidence that nothing major was wrong. I looked at the the first job the reverse gear.
One of the first things Mick said was “please don’t make the forward/reverse wheel ad per drawing!” Which is to roll a rim from 1/8 and then a boss with spokes inserted.. make it solid as it was..! Yes Mick.
So there’s the start point…
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Mr Cook was pleased with the first step…:)
 
Next up was to make the rest of the FWD/REV link assembly. My intention is to make and fit all the new parts then final finish them on the build.

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Link arms roughed out ready for silver soldering…

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Drag Links made and then assembled.

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Weighshaft operating lever and link arm (which i may remake in steel not happy with the top boss alignment when assembled)
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Crank roughed out but not finished
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Assembled i used M2 grub screws for ease of assembly and testing operation on the HP cylinder. These are all pinned on final assembly but i may change to keyed as the 1/16 pins do look oversize just a little, we will see..
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All worked as it should.
During the fit i had to remove the condenser to machine a flat face for the brackets that hold the worm shaft. As i removed the end cap of the condenser I noticed that there had been a small home built…!??
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Clearly someone thought this is a nice secure place to build a house!
Next up strip down and clean, paint the base and make some of the ancillaries that are attached to the engine while paint is curing etc..
 
I made a Bolton triple about 10 years ago using the OB Bolton and Bertinat plans, and yes it was difficult. Looking at your photos I can see that Mr Cook and P1010074.JPGIMG_6173.jpgprop.jpgyou are doing a beautiful job. Mine was just my third model engine and I did not have a metal working background. But it works on steam and regularly features in local shows, working. I wonder if you have seen the book pictured. It was published a year or 2 ago and is obtainable from EJ Winter, Bathurst, Australia and it is VERY good. I just wish that it had been available when I was making my triple.
 
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