Bolton 12 Beam engine from scratch

[deeferdog]

Hello to everyone. This forum has been a big help to me in many ways and I would like to return the favour by showing the progress I am making in building this engine. I paid for the plans from E J Winter and after a week of looking at them in confusion I decided to try a scratch build because I'm too tight to pay for the castings (a serious amount of money) but mainly I honestly doubted whether I had the ability to see it through. A scratch build abandoned would probably pass unnoticed by SHMBO, but a casting purchase of nearly $A2000...unfinished or worse...ruined! It makes me ill to think about it.
For a model, it's a pretty big engine, I believe the finished weight of the cast iron one is over 30Kg. I could understand most of the plans, they are very old, drawn I believe in the 1920's. The measurements are Imperial in fractions with things like 39/64ths and so on. I grew up with that system so it didn't daunt me all that much, just increased my admiration for all those old machinists who used this without calculators.
So, off we go. I've been at it for a few months, made some progress and some mistakes. Here are a few pics of my setup and the facing page of the plans to give you some idea behind the project. I'll post at irregular intervals as time permits, hope you all enjoy.
Regards, Deeferdog.

 

[deeferdog]

OK, the first step was the column, simply because it is the biggest thing on the model and it just so happened that I had a great chunk of aluminium lying under the bench. I have a taper turning attachment that I made for my lathe so I set everything up and away I went. I decided to make the rings on the column, (anyone know what they are called?) separate from the body. My reason was that I would have to make the form tool for the shape and I'm no toolmaker. If I stuffed them, every chance of that, then at least the column would still be in good shape.
Things went quite well. I made the form tool from an old file. It sure chattered but I went slowly and it got the job done. So the most important step has been taken, the first one. I was quite pleased in the end, I now have the column and the ring, or whatever those things are called, and it looks OK to me. More later.

 

[mattty]

Looking forward to watching this build. I would be keen to see some photos of your taper turning attachment.
good luck
Matt

 

[deeferdog]

Hi Matt, thanks for your interest. We don't live far apart as I am on the Gold Coast. The taper turning attachment is fairly primitive, I made it in a hurry a few years ago for a project. It is very accurate. I do morse tapers easily. The compound slide needs to be released from its screw so that it can slide back and forth freely. On my lathe this is easy, undo the cap screw connected to the half nut. The slide is then attached to the TTA. (Taper Turning Attachment). My TTA clamps to the carriageway, simple but it works. There is very little load imposed on the TTA, is is just a guide for the compound slide. The TTA is then adjusted to whatever angle you need, Generally if I'm doing a morse taper, I set the morse arbor up in the lathe and set the TTA from that.
Basically the TTA is a guide set up behind the lathe to which the compound slide attaches. I have shot a couple of pics to help explain. I just realized that this is a different topic and am a bit of a novice at this posting sort of thing. Please accept my apologies if it is incorrect and move it to where it should be.

 

[deverett]

That TTA is brilliant - so simple!

Dave
The Emerald Isle

 

[Jasonb]

Off to a good start

The decorative bead is an "astragal"

 

[Herbiev]

Off to a great start. Looking forward to this build.

 

[deeferdog]

Continuing on with the building. The column needed another astragal at its base. The astragal is the thing I used to call a ring, but I now know better thanks to Jasonb. I machined the second one in the same manner as the first, using my trusty form tool made from an old file. I picked this tip up from somewhere on the internet and for machining aluminium it couldn't be better. I just ground it to the concave shape and gave it plenty of relief on the underside. Plunge cut in a manner similar to using a parting tool and a fair amount of lube. I use lard mixed with a bit of kerosene. There's a fair bit of chatter and squealing from the metal bit it never looked like digging in. The chatter marks polish out easily using various grades of abrasive paper as it turns in the lathe, then buff with a polish compound against a polishing wheel. I have found that time spent on this is well spent if the metal is to be painted as the machining marks really show through the paint. The astragal just slips on down the column until it finds its own location on the taper, I just matched the angle by eye on the compound, any gap will be on the underside and can be filled with a filler prior to painting. As it turned out the tapers matched fairly closely so there is very little gap.
The plans called for a square base on the column but I decided that a round one would look just as good. I turned a spigot of around 1mm depth for location and bolted it to the base of the column, this in turn will be bolted to the engine baseplate using four cap screws. One of the pictures shows this, but I haven't described the making of the baseplate yet so a few things are a little out of sequence, mainly because I did not take many pics at the start as I had not decided to write about this, I wasn't sure there would be much interest.
So now the column is completed. The next stage is to make the beam bearing platform that sits atop the column, I'll talk about that later.
Sorry the last two photos are on there side, No matter how I rotate them before uploading, the result is the same. Any advice would be gratefully recieved.
Regards, Deeferdog

 

[Cogsy]

Sorry the last two photos are on there side, No matter how I rotate them before uploading, the result is the same.

I'll be following this build - looks interesting.

I'm going to guess you're using an iPad or iPhone to take the pictures right? They're very stubborn about which way is 'up' when taking the picture and very tough to change them afterwards. Basically, make sure the 'home' button is at the bottom of the device for a vertical pic or on the right hand side for a horizontal pic. Then you shouldn't have any issues.

 

[Cymro77]

Greetings Deeferdog, looks like a real challenge you have taken on. I will be following along, good work thus far as I see it. My only problem is that your workshop is too darned clean and spacious
Cymro

 

[kvom]

My trial at rotation:

 

[deeferdog]

Thanks to all those who helped with the photography, hopefully I'll get better, and Cymro77, I wish what you said was true but my shed is 3m x 3m (9 x 9) and it generally looks like I'm building a train wreck. One day when I win Lotto..... Onward with the Bolton 12. The bearing platform, that's the only description I can think of, sits on top of the column. A chunk of money got me a chunk of aluminium and I set this up in the 4 jaw. It was whilst I was doing this that I began to realise that this build was going to push the limits, not only of my ability but the capacity of my tools. I knew that machining a flywheel is beyond my lathe, it's 14 inches in diameter, but I began to wonder about the cylinder. Worry about that later.
The machining of the block in the lathe went pretty well, I turned and formed another astragal on the underside and formed a deep spigot to accept the top of the column. I was very careful with the dimensions as I wanted to make sure that the finished height of the platform/column matched the finished height of the casting in the plans, 9 1/4" (235mm). I am only using the plans as a guide as a lot of the detail seems to be omitted but it could just be my lack of understanding.
Over to the mill. I had just finished fitting a power feed to the Z axis and what a joy to use! The hand wheel was at the very top right side of the column and winding the bloody thing up and down was worse than winding the X axis, I fixed that a few months ago. I made the Z axis power feed from an Aldi scroll saw for $50. If anyone is interested I'll post a few pics. Back to the bearing platform. I machined a concave groove around three sides with my new bullnose cutter from Hong Kong. All in all I think it turned out OK. It's attached to the top of the column with an M10 cap screw. Everything will get loctited into position prior to painting. Next is the bearing blocks for the beam, then the beam. Until then.

 

[Jasonb]

In that position the moulding is an echinus. I did have to go and check that one but knew it was not an astragal.

 

[deeferdog]

I thought an echinus was an animal with spines that ate ants.

 

[Blogwitch]

D, if your lathe can't cope with the size, if you have an RT on your mill, then that could be used to turn your large flywheel, in fact when it is mounted up, except for turning it over to do the other side, everything needing to be done, spokes, hubs etc can be done with your RT as long as you have clearance for the billet.
You can drill the mounting holes where the gaps are between spokes, just don't machine out the plates completely, use a hacksaw to finish off.

John

 

[deeferdog]

Thanks John, that's the sort of advice that makes these forums so valuable for us hackers.

 

[ShopShoe]

deeferdog,

Yes, I am interested: Please post some pics of your z-axis motor modification. I am dreaming of doing one someday myself and collecting ideas.

Thank You in advance,

--ShopShoe

 

[deeferdog]

Hi ShopShoe, do I have to put the pics in a new thread or can I do it here?

 

[deeferdog]

At this point I decided to make the base, this is a casting in the kit, with lots of locating lugs and plinths shown on the plan. I brought a piece of aluminium 510mm x 160mm x 12mm (20" x 6.3" x 1/2"). I can just get to all the edges on my milling table, this is gonna be a hell of a steam engine! I cut out the hole for the flywheel crank, then marked and mounted the column, and drilled the bolt holes for the cylinder, apart from that I decided to wait until I was more sure where everything was going to be located, also it will allow me to make small changes that I may have to make.
The bearings for the beam were next, I loctited two lumps of aluminium together, I'm rapidly becoming my suppliers best customer, and went to work. The pictures tell the story. I bored the hole for the bush, machined and fitted the bush blank and then split the bearings with the slitter saw. After drilling and tapping the bearing body to fit the cap, I then drilled the bush and reamed to size. I had a good day and things went well. This doesn't always happen round here.
OK, I'm having a week off in Toowoomba, I will take my tablet and try to do a post or two from there. Thanks to all who are following this, I really appreciate your comments.
Regards, Deeferdog (Peter)

 

[deeferdog]

I have put the pics of the Z axis mod in a new thread under Machine Modifications.

Peter