O.B. Bolton Marine Triple Expansion Steam Engine using castings by AJ Reeves, drawings by John Bertinat

[NMBROOK]

Hi All

This is a departure from my previous builds and a venture into model engineering. Some may say this is a leap into the extreme, akin to building a fully framed ship as your first model.
Yes, this is probably one of the most complex marine steam engine models available in castings.
I am not a complete rookie, I was trained in machining and bench fitting way back in college plus I have worked in engineering for the last 36 years.

On to the subject, I believe Bolton's design is based on an Australian Ferry engine. The engine incorporates an integral Condenser, an air pump and two water pumps.The three pumps are mechanically driven by the engine itself.

For those unfamiliar with steam engines, the triple expansion design reuses steam twice to maximise efficiency.Steam enters the small volume high pressure cylinder. The exhaust steam from this cylinder then passes to the Intermediate pressure cylinder. The exhaust steam from this cylinder then passes to the largest, Low pressure cylinder. The exhaust gasses from this last cylinder are "pulled" out by the vacuum created by the Air pump and into the condenser.The condenser has a water jacket to help cool the steam which is circulated by one of the water pumps.The second water pump is used to keep the Boiler replenished with water.

The model will work as the prototype on live steam. Along with the obvious machining of the engine itself, there is a plethora of valves plus a copper tube matrix to build inside the Condenser.

This project is one of three "Bucket list" projects that I would like to finish before my time is up. My Imara build with two Steam Engines is the first, this is the second. I have found a copy of a book covering the build of the third. Similar price second hand as one of Bordroit's Monographs but worth it given the detail of the model covered.

I have reached the end of what I can tolerate with my cheap 7 x 12 mini lathe. It simply cannot do what I am now asking of it. With that in mind, I have ordered a 10 inch swing 22 inch between centres medium size lathe with stand and digital readout, that is being delivered on Wednesday along with an engine crane on hire to lift and install the thing.

Enough waffle, time for some pictures

Some snaps from the drawings showing the general arrangement. The model will be 10 inches long when complete and weigh roughly 22lbs



Now the castings.These obviously all require extensive cleaning up and machining. Everything os cast in Gunmetal apart from the base, which is aluminium.

The two cylinder blocks, three valve chests and two valve chest covers. The block is split into two and will bolt together sandwiching the Intermediate pressure valve chest.



The aluminium baseplate which houses the main bearings and crankshaft. The six supporting columns, two of which include the condenser casing. The condenser end caps are also shown



The top and bottom cylinder covers and the two piece pistons. The round lugs are designed to be used for initial chuck holding in the lathe and are removed during the later machining stages. Time will tell how useful these are.



The straps for the eccentrics (used to control the valves), the big end bearings, valve blanks and buckles and finally gunmetal bar to make the main bearings.



Finally, the casings for air pump, water pumps, valve rod guides and steam Globe valve.

In addition, numerous sizes of steel bar stock, bronze bar stock plus @ 500 fixings will need to be purchased to build the model

 

[Roger Pellett]

Wow, a really challenging project. I look forward to following it.

Roger

 

[dockattner]

This project is one of three "Bucket list" projects that I would like to finish before my time is up. My Imara build with two Steam Engines is the first, this is the second.

You can't say something like this and then stop...

 

[BradNSW]

Look forward to seeing this develop!! Looks awesome.

Just pulled up a chair to follow.

 

[Bryian]

This is a great project Nigel.

 

[NMBROOK]

You can't say something like this and then stop...

That was deliberate and I thought I would see who if anyone picked up on it

When I was six or seven, my father took me to see one of his friends who lived local to us. The elderly Gentleman was a model engineer and he had a large fully working Steam Locomotive that he had built from scratch. I was in awe of this model and so was my Father. I could not tell you what the Loco was but do remember looking into the cab and seeing the working gauges and hand wheels.

I am getting to the stage where I will have a workshop capable of producing such a model and after this build , I hope to have the confidence to tackle a steam locomotive. I have no intention of pulling a train with passengers behind it, it is all about the construction and making it work like the original. The closest the model will get to running will probably be on a rolling road.There is however a well established Model engineering club fairly local to me with large expanses of outdoor tracks so we will see where this takes me.

Until the Book arrives, the only clues I will give, is a have a passion for American Steam locomotives and the one featured in the book is one of my favourites as it showcases the workings of the steam propulsion at it's best.
I would love to build a Big Boy, but that would exceed both my life expectancy and available budget. I would also need a crane to lift it!

 

[NMBROOK]

Thanks Guys for your interest, I was unsure if anyone would be interested in this sort of build. I thought some may find it a useful point of reference as metal machining is touched on lightly in this forum relating to ship modelling and I hope someone may take something from my techniques that they can apply for making parts for their ship model.

I have downloaded and printed a documented build from Model Engineer Magazine from 1985.This goes through the build and includes drawings and techniques for the jigs required. HOWEVER, this is written with the mindset of milling everything on the lathe (Myford ML7 in this case). I have a large Mill for this. Yes you can mill on the lathe and I can buy attachments to do this on my new machine, but the setup time is considerable and my mill has three axis digital readout so is far more suited to the task and will save some time.

One big timesaver using my equipment is that the structure of the engine is held together with a plethora of bolts connecting base to the legs then to the cylinder blocks. The drawings and books stipulate trial assembly and match marking holes for alignment. I have given this great thought and have come up with a build sequence and fixtures to enable me to do all drilling using Digital readout coordinates. This ensures all holes should fall within one thousandth of an inch and the hardest part of the process is several hours sat down with a calculator "mapping" the coordinates from my chosen point of reference.

The printed documents



I have spent the last year trying to produce a Crankshaft from a round billet of steel. Four failed attempts later I decided to fabricate one. I know the hardest part of this build is the crank so I started there.
The biggest issues was trying to offset turn a 10 inch long 2 inch diameter chunk of steel in the little lathe. The lathe bed is made of toffee and tried to destroy itself once I started spinning the heaving lump. I bolted the lathe to an 80kg chunk of structural steel column I got from work. This helped with the lathe twisting but I then found I could only run very low RPM and the lathe had insufficient torque and kept cutting out mid cut.

I tried to counter this by taking light cuts but then suffered from tool dig in due to the carriage/ tool post set up not being rigid enough.

Pictured below is a fabricated crank I have started to make. The design differs from the plans as I have added counterweights and the parts are locktited together and cross pinned. I am going to park this for now. I really wanted a billet crank and will have a lathe soon capable of doing this. I will have a break from this and focus on the structure of the engine and return to this later.I may well try a sixth redo ! and have a go at turning a crank from solid on the new lathe.



There will be small hiatus whilst I get the new lathe set up and I am also in the process of installing the Z axis digital readout on the mill. The machine came with scales on the X and Y axis and a readout on the quill but none on the mill pillar. I bought the parts when I bought the mill to add this but it has been sat in the box for far too long. I will need this working as I need to be able to digitally measure @Five inches vertically when I come to mill the legs in a fixture. The quill travel is far too short.

 

[AllanKP69]

So different of a project. I am in awe and will stay tuned, VERY COOL!!
Allan

 

[Namabiiru]

Pulling up a chair and a drink to watch your progress

 

[NMBROOK]

Well my new lathe turned up today just half an hour after the hire engine hoist had been delivered.

Everything was going so well, until it wasn't........

I bolted the stand together and sat the drip tray on top and realised the tray was noticeably shorter than the stand

They had sent the stand for the long bed version of my Lathe. The cabinets at each end are identical it is just two sheet steel cross pieces that are different.

I phoned Chester who supplied the lathe who said they would source the correct items and have arranged to collect the incorrect pieces tomorrow.

I have been able to install the Lathe and bolt it to the floor ensuring the gap between cabinets is correct. The DRO was preinstalled but the control unit just needed bolting on presumably to prevent damage in transport. I have had a very quick go to check the controls and all is good.

I will post some proper pics once I have the stand completed and all the anti rust protective gunk is cleaned off. A couple of pics of the lathe uncrated and ready to be lifted into place. Looks kind of small in the pics but it isn't. It is actually larger and more powerful than a regular Myford ML7. It also weighs nearly double.

Really looking forward to putting this to work, it is just soo heavily built compared to the mini lathe it replaces and the motor is four times more powerful.

 

[johnv]

Thanks Guys for your interest, I was unsure if anyone would be interested in this sort of build. I thought some may find it a useful point of reference as metal machining is touched on lightly in this forum relating to ship modelling and I hope someone may take something from my techniques that they can apply for making parts for their ship model.

I have downloaded and printed a documented build from Model Engineer Magazine from 1985.This goes through the build and includes drawings and techniques for the jigs required. HOWEVER, this is written with the mindset of milling everything on the lathe (Myford ML7 in this case). I have a large Mill for this. Yes you can mill on the lathe and I can buy attachments to do this on my new machine, but the setup time is considerable and my mill has three axis digital readout so is far more suited to the task and will save some time.

One big timesaver using my equipment is that the structure of the engine is held together with a plethora of bolts connecting base to the legs then to the cylinder blocks. The drawings and books stipulate trial assembly and match marking holes for alignment. I have given this great thought and have come up with a build sequence and fixtures to enable me to do all drilling using Digital readout coordinates. This ensures all holes should fall within one thousandth of an inch and the hardest part of the process is several hours sat down with a calculator "mapping" the coordinates from my chosen point of reference.

The printed documents

View attachment 531551

I have spent the last year trying to produce a Crankshaft from a round billet of steel. Four failed attempts later I decided to fabricate one. I know the hardest part of this build is the crank so I started there.
The biggest issues was trying to offset turn a 10 inch long 2 inch diameter chunk of steel in the little lathe. The lathe bed is made of toffee and tried to destroy itself once I started spinning the heaving lump. I bolted the lathe to an 80kg chunk of structural steel column I got from work. This helped with the lathe twisting but I then found I could only run very low RPM and the lathe had insufficient torque and kept cutting out mid cut.

I tried to counter this by taking light cuts but then suffered from tool dig in due to the carriage/ tool post set up not being rigid enough.

Pictured below is a fabricated crank I have started to make. The design differs from the plans as I have added counterweights and the parts are locktited together and cross pinned. I am going to park this for now. I really wanted a billet crank and will have a lathe soon capable of doing this. I will have a break from this and focus on the structure of the engine and return to this later.I may well try a sixth redo ! and have a go at turning a crank from solid on the new lathe.

View attachment 531552

There will be small hiatus whilst I get the new lathe set up and I am also in the process of installing the Z axis digital readout on the mill. The machine came with scales on the X and Y axis and a readout on the quill but none on the mill pillar. I bought the parts when I bought the mill to add this but it has been sat in the box for far too long. I will need this working as I need to be able to digitally measure @Five inches vertically when I come to mill the legs in a fixture. The quill travel is far too short.

I made a Bolton 9 Triple Expansion Steam Engine from bronze castings about 10 years ago. It has been running on steam at exhibitions since then. The build was written up on johnsmachines.com and videos of it running on steam are on you tube.

I have made a number of steam engines, and I found the triple was the most difficult. It took me 3 years, including 2 long breaks to keep a grasp on my sanity.
I STRONGLY recommend that you obtain a new book "Making A Triple Expansion Steam Engine OB Bolton No.9" by James Clark. Clark takes a rational and sensible and researched approach to the build and I wish that I had available that advice when I struggled with difficult aspects of the build. The photo is of my triple nearing the end of construction, being run in by turning it on a lathe.
I will follow your posts with great interest. Good luck!
BTW, I made a solid crankshaft. Successful on the second attempt.

 

[NMBROOK]

I made a Bolton 9 Triple Expansion Steam Engine from bronze castings about 10 years ago. It has been running on steam at exhibitions since then. The build was written up on johnsmachines.com and videos of it running on steam are on you tube.

I have made a number of steam engines, and I found the triple was the most difficult. It took me 3 years, including 2 long breaks to keep a grasp on my sanity.
I STRONGLY recommend that you obtain a new book "Making A Triple Expansion Steam Engine OB Bolton No.9" by James Clark. Clark takes a rational and sensible and researched approach to the build and I wish that I had available that advice when I struggled with difficult aspects of the build. The photo is of my triple nearing the end of construction, being run in by turning it on a lathe.
I will follow your posts with great interest. Good luck!
BTW, I made a solid crankshaft. Successful on the second attempt.
View attachment 532478

Hi John

I feel honoured to have you following along. I am very familiar with your blog and have read it more times than I care to mention.

Yes, I believe you not only machined your crank from Billet, but you did it in Stainless Steel.

I have one question for now. None of the builds I have seen mention anything about subtracting an allowance for gaskets between the blocks and valve chests.

Are you using gaskets and if so did you knock anything off?

Your model is built from the AJ Winter castings which I feel are slightly superior and more extensive than Reeves versions. They are also slightly cheaper but I would not relish the postage and import taxes to bring those into the UK.

I have seen the book on A J Winter's website and have been trying to find it locally, but so far no joy other than ordering it from OZ.

 

[johnv]

Hi John

I feel honoured to have you following along. I am very familiar with your blog and have read it more times than I care to mention.

Yes, I believe you not only machined your crank from Billet, but you did it in Stainless Steel.

I have one question for now. None of the builds I have seen mention anything about subtracting an allowance for gaskets between the blocks and valve chests.

Are you using gaskets and if so did you knock anything off?

Your model is built from the AJ Winter castings which I feel are slightly superior and more extensive than Reeves versions. They are also slightly cheaper but I would not relish the postage and import taxes to bring those into the UK.

I have seen the book on A J Winter's website and have been trying to find it locally, but so far no joy other than ordering it from OZ.

Hi Nigel, and thankyou for the compliment.
With respect to gasket allowance between blocks and valve chests, I made no special allowance, and I do not think that mattered. I did use gaskets. Cannot remember the thickness exactly but they were on the thin side. My friend Stuart cut me a couple of sets of gaskets using his laser cutter. I think that I still have the dxf file somewhere. Would you like a copy? Actually, they will only be of use if the Reeves version really is the same as the Oz version.
p.s. I looked up James Clark's book and he states that there is a gasket allowance of 10thou/0.25mm for those gaskets and if different thickness gaskets are used the machining of the surfaces must take the difference into account. I must have just fluked that one in my build.
The book is a must. I am almost tempted to make another triple in order to use the excellent information it contains. Just kidding. Not that insane.
Best, John

 

[Peter Voogt]

I just found the beginning of your very interesting build log, Nigel. Hopefully there's still a chair? I'll enjoy following along.
Regards, Peter

 

[NMBROOK]

I just found the beginning of your very interesting build log, Nigel. Hopefully there's still a chair? I'll enjoy following along.
Regards, Peter

Plenty of chairs available Peter, the more the merrier

 

[NMBROOK]

Hi Nigel, and thankyou for the compliment.
With respect to gasket allowance between blocks and valve chests, I made no special allowance, and I do not think that mattered. I did use gaskets. Cannot remember the thickness exactly but they were on the thin side. My friend Stuart cut me a couple of sets of gaskets using his laser cutter. I think that I still have the dxf file somewhere. Would you like a copy? Actually, they will only be of use if the Reeves version really is the same as the Oz version.
p.s. I looked up James Clark's book and he states that there is a gasket allowance of 10thou/0.25mm for those gaskets and if different thickness gaskets are used the machining of the surfaces must take the difference into account. I must have just fluked that one in my build.
The book is a must. I am almost tempted to make another triple in order to use the excellent information it contains. Just kidding. Not that insane.
Best, John

Thanks for the kind offer John, not sure how they will fair against Reeves castings and I am intentionally going to machine the blocks and intermediate valve chest narrower so the cladding sits flush to the end valve chests.The Gasket material comes in two thicknesses that I can obtain, 1/32" and 1/64". It adds ups when I have four gaskets in total between the end valve chests.

I was reading your blog again last weekend funnily enough and revisited your first page where you show the original drawings by OB Bolton. Rightly or wrongly I do like the design with flanged ends. Now I know that causes a problem installing eccentrics over the crank ends and originally set myself the goal of if I did a billet crank to machine the eccentrics into it.

I did draw out where all the index points would need to be to turn everything between centres but hit a problem with these centres being too close together to be practical, however I now know how to get round this after looking at builds of the locomotive featured in the book I have on order.

This method employs throw away end caps for the crank with centre drill marks for only one cylinder. The end caps are held to the crank by three countersunk bolts at 120 degree spacings. These discs are rotated through the three positions to turn the eccentrics and Big End Journals in three separate stages. Sounds feasible enough, execution will be interesting.Obviously the tapped holes will be close to the outer 2" diameter of the initial billet and be machined away when the crank is turned to size.

 

[Roger Pellett]

I am looking forward to watching this. My education involved design of shipboard steam power plants and my career involved engineering of shop fabricated piping (pipework) for the electric generation industry. Building a model steam engine has long been an ambition. The more that I read posts from the experts like you, the more that I realize that belong in the stands as a spectator, not on the field playing the game.

Roger

 

[AllanKP69]

Building a model steam engine has long been an ambition. The more that I read posts from the experts like you, the more that I realize that belong in the stands as a spectator, not on the field playing the game.

You won't know until you give it a try Roger.

 

[NMBROOK]

I am looking forward to watching this. My education involved design of shipboard steam power plants and my career involved engineering of shop fabricated piping (pipework) for the electric generation industry. Building a model steam engine has long been an ambition. The more that I read posts from the experts like you, the more that I realize that belong in the stands as a spectator, not on the field playing the game.

Roger

Hi Roger,

I am no expert and this will be my first model steam engine build from scratch.I am a gluten for setting the bar extremely high for myself otherwise I would have chosen something simpler

Yes I have an engineering background but so do you. I agree with Allan, you don't know unless you give it a go. If you already have suitable machines at your disposal then it doesn't have to be a costly experiment. PM Research do some simple unmachined kits that are made in the US so you won't get stung by taxes and most have extensive build videos on YouTube. Blondihacks and Joe Pie have some good build videos for their models. Check it out if you want to see what's involved. Don't let Joe Pie scare you off, yes he is the owner of a professional machining business, but he also has some good pointers and does cover the basic stuff

 

[slicksleeve]

OMG, I'm so excited about this build and what I'm about to learn! Leave nothing out please.