Cheap Engine Turning
A few posts ago I posted some photos of the Koffiekop Stirling Engine, the top plate of which I had decorated with “engine turning”. I had borrowed the engine turning tool and it worked well. But I really wanted the circles to be bigger than the 5mm diameter which the Brownells kit produced.
Today I experimented with disks punched out of metal polishing material, glued to the end of same diameter dowel. (1/2″ = 12.7mm diameter). I used Super Glue, and no problems with adhesion.
The dowel was attached to a chuck in a drill press. Running at about 200-300 rpm, and pressing firmly. No extra cutting compound ( I imagine that these metal polishing pads already have an imbedded cutting compound). If I was using washing up Scothbrite type material, I would expect to have to add a cutting compound.
The steel I was testing had surface rust.
Very happy with the result. Next time I will use CNC positioning to pattern the circles, and overlap the circles so the crappy rusty steel disappears.
I understand that if engine turned surfaces are oiled, they are relatively rust resistant. Presumably some oil remains in the microscopic grooves.