I cut the aluminum bar stock to the required diameter and cut the step which will later be threaded and the combustion chamber. I center drilled, drilled and used a home-made shaping tool for the combustion chambers. With these steps done it was time to cut the fins. Pucker! Aluminum might be a free cutting material but when it's cutting and the material that you're cutting gets super hot from friction you can get what's known as a pin. This is the same thing you get on a file when the metal sticks to the teeth. You have to constantly lubricate it otherwise the pin can deform, in this case) the thin fin and possibly break the tool. I'm sure many of you have cut aluminum and had it stick to the flutes of your end mill. Not a happy situation.  Anyway I got the heads cut and finned.

Hi Kim,

Enjoying this build immensely, if quietly.

For your boiler cutout consider using a hole saw (probably bi-metal for steel) - they are cheap and low on drama if all you want is to remove most of the material and file from there.

All the best,

Martin

Thanks guys! Its great to see it coming together!   

Impressive assembly, looks very nice!

Dave

While I was off prepping for the RC submarine run at the pool today, the elves got the flanges installed on the chain drum supports and got them painted too. Here they are after installing them, along with setting the chain guides/pipes in place underneath to mark them for final cutting and installation:

After finishing the chain guides, next up will be to make the ratchet mechanisms for the drums, then the brake bands/control wheels. This picture better shows where this engine assembly will fit inside the rope winches/engine in the background, this engine will be about where the stack of papers is under the rope drum shaft.