I will post one more on the pulley building process. I probably won't use this pulley on the Unimat 1, since I've discovered that it has plenty of power with the small pulleys and they will give me the speed ratios I need. This larger pulley will probably become a drive pulley on one of my DB200 machines. I just eyeballed the whole thing, no drawing or measuring, but it looks like it will work fine. I will need to machine the bore, face the inner side flat and install a set screw. This piston material is very gummy and sticky and doesn't machine nicely. I'm not a machinist, just a wanna-be. I managed to finish the pulley with only a couple of wrecks and no spilled blood.
I discovered that I couldn't properly support the pulley to part it off of the piston scrap. But, I tried... and this resulted in a crash when the parting tool snagged, and popped out of the holder, which also pulled the pulley out of the 3 jaw chuck. Sigh... dings in the grooves, but nothing that can't be lived with. My live center wouldn't reach inside the piston, so I tried to part it without support... DUMB MOVE. Anyway, I just thought... I should have found my dead center. But, I didn't and decided to use the small bandsaw to part it. Broke the blade!!! Finished the cut off with a hacksaw and finished the basic pulley machining on the big lathe.
Here are some pics. The piston in the pic is the same style as the one that the pulley came out of. The head is domed, but this one is faced off for the index center project. Note the ratty finish, nasty stuff. Anyway, here it is...
A little work with a jeweler's file will fix the dings good enough to work.