Author Topic: The Bolton No 5 Vertical Open Column Steam Engine  (Read 14676 times)

Offline MJM460

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The Bolton No 5 Vertical Open Column Steam Engine
« on: October 03, 2020, 12:53:00 PM »
So far all the engines I have built have been my own design and made from Bar stock.

A little while back, I was given a set of castings for the Bolton no 5 vertical open column steam engine, a very generous and much appreciated gift.  So this will be my next build.

It came with a booklet of construction notes, but unfortunately the plan was missing.  However, a phone call to E J Winter in NSW soon had the plan on the way.  This was pretty good service, as the castings seem to be no longer listed on the web site.

I don’t know if this engine is well known to forum members from the Northern hemisphere.  O. Burnaby Bolton started selling model engineering supplies in Australia around 1920, and continued through to his death around 1974.  The business was purchased, but the new owners sold it on to E and J Winter about 1978, who continued to operate until their retirement about 2016.  The new owner, Ben De Gabriel, continues to operate under the E and J Winter name, and still sells casting sets for some of the original Bolton designs.

The original Bolton drawing from 1951 had some construction notes in a side panel.  Ernest Winter redrew the plan in 1981, and followed up with a booklet of revised construction notes in 1995.  So that is briefly where this engine came from.

The box contained all the castings necessary to build the model, but left me to supply fasteners, and rods for piston and valve rods and columns.  Most of the material required was found in my store of supplies, so I feel that it was pretty well complete.  When I received the castings, some reference surfaces had machined, and as I am confident that these will have been done well, it was a great help to a beginner to castings to have these surfaces as a starting point.

I have learned from the experts on this forum that the first step with an engine from castings is lots of casting fondling, so that activity kept me busy in the many necessary breaks from trouble shooting that governor circuit.  The castings seemed to be good quality with enough metal for all the parts as designed. 

The plans have both metric and imperial dimensions to suit the various user groups for this model.  Older modellers apparently prefer imperial to suit their tooling if they have been at the game for a long time while schools, and people newer to the hobby, like me, often have mostly metric tooling.  I did a careful check of the metric dimensions by constructing assembly drawings so I could easily check the chains of dimensions that go over multiple parts.  This was instructive in highlighting the critical dimensions and clearances.  The process highlighted some dimensions that I chose to modify to make it easier to make with the tools and skills I have, and I chose to use metric fasteners, and mostly metric threads.  In the end, I don’t think I identified any real errors, and little changes I made were more the inevitable result of my deliberate adjustments.   I concentrated more on choosing dimensions that would work, rather than identifying discrepancies in the original dimensions.  Probably more accurate to say I have not done a detailed drawing check, as would be necessary for a precision scale model, just a rationality check that it would all fit together with the small adjustments I felt I had to make.  Somewhat tedious process, but a great introduction to the build for me, and a very necessary step.  I will touch on some of the more critical items at the appropriate point in the build.

Enough introduction, it’s time to get making chips.  I have attached a photo of the castings as received, sitting on the plan which gives an idea of the style of engine.  It is 16 mm bore and stroke, with a cantilever slide bar style cross head.  It has a slide valve, driven by a single eccentric and a marine style flywheel, with a low profile cast baseplate.

I hope you enjoy following my first venture into castings.

MJM460
The more I learn, the more I find that I still have to learn!

Offline propforward

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #1 on: October 03, 2020, 01:04:51 PM »
I’ve always thoroughly enjoyed your engines, and I have no doubt that this will be a superb build. I shall enjoy following along very much.
Stuart

Forging ahead regardless.

Offline Ramon Wilson

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #2 on: October 03, 2020, 01:48:03 PM »
Hi MJM,

As I progress slowly toward the end of my current build I'd just like to wish you well on the start of your new journey. It might be a tad smaller than the Corliss but never the less 'journey' it will be so good luck for a successful outcome :ThumbsUp:

All the best

Kind Regards - 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 iancchesney

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #3 on: October 03, 2020, 05:28:41 PM »
Hi MJM
It looks very similar to the E T Westbury Trojan engine available from AJ Reeves in th UK.
Regards
Ian

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Offline Zephyrin

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #4 on: October 04, 2020, 08:59:34 AM »
hi
it looks to be a cute model...

at a glance at the plan shown I would make the columns a tad larger as they look a bit flimsy, and without these awful adjusting nuts for height, you can turn 4 identical columns !

Offline deltatango

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #5 on: October 04, 2020, 11:27:37 AM »
Hi MJM,
Welcome to the world of castings! I'll be following along.

Ben at E & J Winter has been a pleasure to do business with, his may be one type of business that may be doing all right just now, hope so!

Regards, David
Don't die wondering!

Offline MJM460

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #6 on: October 04, 2020, 12:45:51 PM »
Hi Everyone, thanks for the nice comments, and thanks also to those just looking in.

Propforward, I suspect that I would really appreciate that dro you are installing, but COVID interrupted my plans so I will be building this with what I can improvise.

Thanks Ramon, I have learned so much from reading your threads, and I am certainly not ready for the Corless, but I hope to do justice to this little engine, and learn a bit more along the way.  Big advantage of the small ones is that I can lift them.

Iancchesney, I guess there are only so many ways you can arrange a crank, conrod, cylinder and slide valve, so it is not surprising that it resembles another design.  I guess the unusual feature is that slide bar crosshead guide.  I might still add a lower support for the guide rod, I will see how it looks when I progress enough to check clearances in 3 D so I can see what is possible.

Hi Zephyrin, I think that you are right about the diameter of the columns.  The nuts make an easy way for a beginner to get the heights equal by adjustment.  Perhaps I could make fancy nuts that would hide the exposed threads and look a little more elegant.  Another thing to consider for when I get to the point of making them.  I need to think about holding the engine down as well.

Hi Delta Tango.  Great to have you following along.  I am sure I will need a bit of advice at times along the way.  I also found Ben pleasant and helpful.  It would be good to see him do well as so many sources are disappearing.

I want to see what the cast bronze is like to cut, and a simple place to start seems to be to work on that base casting.  It will also give me something to start building on.  I have worked out what height I can make with the casting, so I will just skim the bottom edges, as this will be enough to keep the flywheel clear from a mounting board.  I also checked the largest flywheel I can make with the supplied casting, a little bigger than the design, and still clear with the base casting height I have chosen.

Not much progress today, it’s amazing how much difference losing an hour makes when we sleep in on the first day of daylight saving.  So first progress photos tomorrow.

MJM460
« Last Edit: October 04, 2020, 12:48:54 PM by MJM460 »
The more I learn, the more I find that I still have to learn!

Offline MJM460

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Re: The Bolton No 5 Vertical Open Column Steam Engine - Base Casting
« Reply #7 on: October 05, 2020, 12:15:30 PM »
Today’s progress involves machining the base casting. 

My preliminary fondling and study revealed not only the base height achievable but also the width of the bars, or more importantly the slots for the crank disk and eccentrics.

I clamped the base, machined reference side down, on a tooling plate on the rotary table for convenience in mounting options, and allowing me to turn the base so the edges could be machined in just four directions.  It ended up 12.5 mm high, which is more than the design, but is sufficient to keep the largest flywheel I can make from the flywheel casting clear of the eventual mounting board, and is not critical for any other reason.

The photos show the raw casting edge ready fo machining, the finished edge, measuring with the depth micrometer, mainly for the practice, and the castings with the bars cleaned up and the slots widened to accomodate the crank disk and eccentric.

The bronze machined quite nicely, and while only a small job, success reduced my anxiety about starting.  A much bigger result than appears from the completed task.  I think it was the knowledge that I couldn’t just cut off another piece of bar stock if I mucked it.

Not an end to the fondling, but I have done enough to feel that I have identified the critical bits to understand at this stage, and what can be further studied later.

Thanks for looking in,

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 #8 on: October 05, 2020, 10:46:21 PM »
Hi MJM
It's good to see your progress!

It's also good to know that the casting had plenty of metal on it to clean up to drawing dimensions (this definitely isn't always the case) this gives a bit more confidence that the other castings may show the same generosity.

Your clamping arrangement worked out well, I've failed several times when clamping down gun metal castings, that metal can be so soft as to be difficult to hold without marking it. In my experience uncoated tools have sharper edges and can leave a better finish on soft metals, this is particularly true for aluminium but also the bronzes. Other people may want to comment on this.

David
Don't die wondering!

Offline gary.a.ayres

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #9 on: October 05, 2020, 11:20:07 PM »
This will be enjoyable and informative!

Good luck with the project.

Will be following along...

gary

 :popcorn:

Offline MJM460

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #10 on: October 06, 2020, 12:45:21 AM »
Thanks David.  All my preliminary fondling indicates that all the castings do have enough metal, and only minimal misalignment of some pattern halves.  Will all be acceptable cosmetic “features”.  Overall the castings seem excellent.

I use mostly HSS tools with zero top rake on brass and bronze, and so far have not experienced the issues that some have reported.  Fingers crossed for this to continue.  Some time back, I purchased one of those sets of brazed tip tools.  I have been shown how to sharpen them (for any future purchases) and made a holder block to set the centre height, and they are also working well.  I wonder if that zero top rake is part of the secret. 

Hi Gary, good to have you following along.  I will be delighted if my processes are at all instructive.  Perhaps in those areas that we beginners still have to learn, while the experts learned those things so long ago they have forgotten that a beginner does not know that.  I am fortunate to have a good mentor as well as the many members of this wonderful forum.

A busy day ahead with zoom meetings and stuff, but I hope to have some progress to report by the end of the day.  There are some small pins which have to screw up to the shoulder, so I am thinking I would like to get those out of the way.

Thanks to everyone looking in.

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 #11 on: October 06, 2020, 08:32:31 AM »

A busy day ahead with zoom meetings and stuff, but I hope to have some progress to report by the end of the day. 

MJM460

The unreasonable demands of real life keeping us away from our workshops as usual!

 :-\

Offline MJM460

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Re: The Bolton No 5 Vertical Open Column Steam Engine - small pins
« Reply #12 on: October 06, 2020, 10:16:26 AM »
Having tackled my first experience in machining the cast bronze, the other thing I want to get out of the way early is making the small pins for the crank pin, crosshead pin and valve pin.

The crankshaft is also threaded on one end and has a shoulder which the crank disk has to sit squarely against. 

The crankshaft is specified as 1/4” with 6 mm designated as the metric alternative.  I would normally have used 6 mm with an M5 thread up to the shoulder.  However, I long ago found that despite the years since we went metric, sometimes the stockist has metric size materials, other times it seems to be imperial.  So after persisting for many years with only metric tooling, I purchased a set of ME threads and dies.  Even if everything else metric these seem to nicely fill some of the gaps between metric sizes when things get tight.  It was just as well I did that some time back, as when I went to the shelf for some 6 mm rod, while collecting materials in preparation for this build, it was all 1/4”.  So 1/4” it is.  The 7/32 x 40 ME thread provides a very small but I hope adequate shoulder.  One of my small number of internet purchases, very necessary in lockdown, was a 1/4” reamer for that shaft.

I started by making a test plate with tapped holes for the threads I plan to use, and also and also drilled and reamed holes so I had samples for those also.  Having this plate made will allow me to check that threads have been cut deep enough, and that I can screw the plate right up to the shoulder.

All my threads are cut with tap and dies.  I start by turning the right outside diameter, then a groove against the head so a nut can screw right up to the head.  I always found even that was not enough, until I realised that I was cutting the groove to the tapping drill size.  Seventy five percent thread engagement, no wonder the nut would not reach the shoulder.  So now I calculate the groove depth for 100% .  And of course a tiny chamfer at 30 degrees for the lead in, ( not always very visible in the photos on these small threads.  Finally I put the die in the holder with the open side of the holder towards the tail stock, so I can use the face of the chuck against the back of the die to ensure it starts out straight.  Then I follow the die with gentle pressure on the tailstock handwheel to keep it straight as I turn the chuck by hand.  The plate threads on to sit securely against the shoulder, which is helpful to know before I part off.

On the crankshaft, I just cut a groove with the parting tool for the overall length to provide a clear line, then cut it through with a junior hacksaw, the groove keeps the saw in place and leaves an easily tidied up shaft end.

To finish the bolts, I transferred the collet with the rod and threaded end still in place to a hexagonal collet block, gripped in the mill vice and machined the flats for the head.  I made sure that each one was sized nicely for the appropriate spanner, and the flats were long enough to part off, and leave enough already machined hex for the nut.  Finally the collet was moved back to the lathe to part off the bolt, drilling and tapping and parting off the nut.  I even ended up with a spare M2.5 nut.  But I did not get to the valve rod pin.  It was supposed to be M2.0 or M 2.2, but it might end up being M2.5.  I will see when I get the fork for the end of the valve rod made.

Not a big day I guess, but it is surprising how much time the necessary chores take along with a zoom meeting or two so even in lockdown there does not seem to be time for much more.  So that’s it for today.

MJM460

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

Offline MJM460

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Re: The Bolton No 5 Vertical Open Column Steam Engine
« Reply #13 on: October 06, 2020, 10:29:49 AM »
That’s it Gary.  Still I can’t complain to much.  I get to read the new forum posts each day, spent too long on George’s gear box thread this morning, and the newspaper (electronically) each evening, and my roof is still intact so far.  Also walk three km with my wife along the creek each day, wearing masks of course and three square meals.  Definitely a civilised way to sit out a pandemic.

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 #14 on: October 06, 2020, 07:31:12 PM »
Indeed. Despite there never being enough hours in the day, there is much to be thankful for. May your roof remain intact!

Off to a good start with the build. I admire your capacity to postpone gratification in making these pins so early in the process, rather than starting the more glamorous parts!


 

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