Global Scale Modeller

Morning all.

I decided it was time I used my machines to build something other than tooling, so I've chosen this as my first engine build. This is a model of a simple steam (or in my case air) powered engine designed my Elmer Verberg. This is a relatively cheap build, there are no castings, it's all built from bar stock so only around £30 in metal (although in fairness several thousand in tooling).

The plans and stock.







I'm starting with the foot and frame, these were rough cut from 10x50mm aluminium then squared up.​





And the features formed.







The most nerve racking part of this was the long 3mm hole from the end all the way down to the crank pin hole, around 60mm.

Morning all.

Started on the cylinder yesterday. This is a relatively simple block, 20x20x37mm with a 14mm hole bored 35.5mm deep.

I started of by squaring up the stock and reducing it to the 20x20mm square, but leaving it over long at this stage. This was then stood upright in the mill and the hole bored with a variety of drills and finally a 14mm 3 flute slot drill (milling cutter). The surface finish is actually pretty good, it looks a little rough in the photo but is actually very smooth. However I will end up giving this a polish later down the line.





With the hole bored slightly over-length I could then use my depth micrometer to find out how much over it was , then fly cut the end of the cylinder to get the precise depth.





I ran out of time after this so still have to reduce the other end to overall length, then add some holes and chamfers.

Steam engines ...oooh so cool.
If I had the gear definitely my choice of projects.

Cheers Digger. This will be less steam and more air, at least until my skills progress enough to build a model boiler.

Morning all.

I decided to brave my very cold workshop last night in order to finish the cylinder. This consisted of 5 holes, one all the way through to meet up with the steam passage and 4 threaded M3 to mount to the frame, and a couple of aesthetic chamfers.





And here it is mounted to the frame. A quick blow through with air confirmed the holes all line up and I will be able to get steam/air to and from the piston.



Think I might tackle the flywheel next.

Nice work. Looking forward to the fly wheel and piston.

Cheers Digger.

That is some super clean metal work
Great stuff, thanks for showing

Nice job of machining! I reckon even my old apprenticeship instructors would be impressed!! I certainly am.

Cheers guys, it's a lot of new skills to learn, but I'm enjoying it.

Morning all.

I got back to work on the Elmers this weekend. I decided instead of making the flywheel I would concentrate on some of the smaller parts.

First up was the bearing, which also acts as the steam/air intake, and the inlet pipe bracket.





Then on to some very small parts, the crank pin and wrist pin.



And the crankshaft. Having made this I think I now understand how it works. It has a large and a small flat at 180 degrees, the small flat has a hole through it that meets up with a hole drilled along it's length. As the engine turns the long flat allows steam/air to travel up the long hole in the frame and across into the piston. As the engine continues to turn the piston will then push the exhaust gas back along the passage where it will meet the small flat, and exhaust out the hole in the end of the crankshaft.





Finally I decided to attempt what to me is the hardest part to machine, the connecting rod. This is made from 3mmx6mm flat brass bar. After locating the holes on the mill, it needed to be turned on the lathe. Holding such a small part in the 4 jaw is difficult, so I made up a fixture to help with that.







Then it was just a case of using a parting tool to locate either end of the taper, and turn down the central section.



This still needs the ends cut down and rounded, but I am more than happy with this part.

Morning all.

Small update, I braved the cold yesterday and finished the connecting rod. This just involved sawing off the ends and filing a small radius.



As I had already made the wrist pin (and was already cold) I decided to finish the sub assembly by making the piston. This was a simple turning operation, the outside was turned to a sliding fit with the cylinder, some oil grooves added, then the inside bored out to two diameters and a cross hole drilled. This is the completed assembly and a rough idea of how it will look when installed.




There's only a couple more parts to make, I think I will machine the crank next which will complete this side of the engine.

Looking excellent - well done!!!

Cheers all.

Morning all.

Despite storm Bert I managed to spend most of the weekend in the workshop. There were two main components left to make, the crank and flywheel. These were made from the same piece of 50mm brass round bar.

I started on the crank first. This was an interesting piece as it started on the lathe, went to the mill, back to the lathe and a final trip on the mill.

This is it after the first turning operation, which involved bringing the overall diameter to 28mm, stepped down for the boss to 10mm and the 5mm drilled and reamed central hole added. Then it was over to the mill.



The piece was located off the central hole, the second M3 tapped hole added for the crank pin, and the scallops cut, then back to the lathe to be parted off.





While the stock was set up in the lathe I switched to machining the flywheel. This was reduced in diameter slightly just to clean up the edge, a 6mm central hole drilled and reamed, and dished out. This appears to be more cosmetic than necessary and went OK. I used a form tool I had made a while back and had quite a lot of chatter, I really need to grind a proper trepanning tool.



Brass is lovely to machine, cuts really easily and leaves a nice finish, but the mess!



With one face of the flywheel completed it was necessary to part off and turn the other side. My parting blade isn't deep enough to reach the middle of such a large part, so I went as far as I could and hacksawed the rest. With the flywheel flipped over it needed mounting back on the lathe concentrically, so a piece of aluminium bar was chuckled up and a 6mm spigot turned. The central hole wasn't visible yet (brass is expensive so I had only drilled just deep enough) so it was initially held on with CA glue until the waste material was faced off, then once the hole was fully visible the arbor was drilled and tapped for a retain screw, and the remaining features machined.







Back to the crank, this needed a radius added so I made up a couple of filing buttons and removed the excess material by hand.



Both the crank and flywheel needed a means of securing to the crankshaft, so each was cross drilled and tapped M3 for a grub screw. And that was the crank and flywheel completed.





Now, remember that long hole in the frame right back at the beginning of the project? Well that needed to extend into the bearing so that the steam/air could get too and from where it needed to go. The bearing, inlet pipe and inlet pipe bracket were fitted to the frame. The bracket and pipe determine the fixed position of the bearing, so the assembly was placed upright in the mill and a 3mm drill passed down the long hole and drilled through the bearing.



There were two last small parts to make, the plug for the end of the long hole, and a pin for the cross hole on the flywheel for the grub screw to bear against.



These are all the competed parts.



And the assembled engine.

Some proper engineering going on here

Cheers Kev.

Marvellous work, well done.

Cheers Digger.