Thanks for that picture of the mill for adjusting cylinder gap.
It solved my problem.
I recently picked up an almost new Dance by Pietta with about a .030 gap.
Last night, using my mini-mill, I whacked .025 off the front of the frame (the front surface looked like it was finished by scraping it on the concrete driveway).
Today when it warms up I need to take a few thou off the forcing cone to square it up and give me about 8 thou of gap.
Funny thing is the arbor and wedge fit is perfect now.