I have a project to machine some cutouts in 3/8 x 2 6061 aluminum flat bar. The cutouts are various sizes from .600 x .900 to 1.25 x 1.25 but all require square corners for the electronic components to mount. Couldnt convince the customer to go with .06 radius so I could use a 1/8 endmill, so now I must square out the corners. If it was one or two I would file them, but I have 200 pcs with 3-4 cutouts in each so that's a lot of corners. I read somewhere a long time ago about the use of a square punch used in the CNC mill utilizing an M19 to lock the spindle and then programming a series of strokes over, down, back and out repeating mooving in a few thousandths each pass. Sounds feasable to me, was wondering if anyone out there has done this and would be willing to share the process, tooling resource and other points that might help.