Stuart No 4 Steam Engine

[f350ca]

Keep stealing time to play.
Made an adjustable lap to finish the bore where the cross head runs.
Have some reamers for tapered dowel pins, thought that would be a good taper, found one with straight flutes, figured I could chuck it up and adjust the taper attachment to it. Wrong, turned out to be a Brown and Sharpe taper, hence the mandrel I made didn't quite match the tapered hole I did in my blank using the actual spiralled tapered reamer. So then I needed to make a mandrel to run between centers to set the taper attachment and adjust the taper by offset to z travel to match the 1:48 taper.
The lap worked but was too adjustable, had to clamp one end to get it to stop sliding up the mandrel and slipping on it.


Working the bore using valve lapping compound.



Got the finish I'd hoped for, smooth but not gloss that wouldn't hold oil.



Forgot to take pictures when I was machining the base and crank case. Now need to make some studs and scaled nuts.



Next will be the bearings. Started the caps. They're cast bronze. Machined them to size and reamed the mounting holes to fasten them together with dowel pins while I turn the outer profile.