I was working on the pin spanner wrench for the trim-tilt unit, and drilled a 3/4" hole in either end to be used with a mandrel and dividing head to drill the pin holes, then sawed and milled out to fit over the rams. The old silver & deming bit left a bit of a burr on either side of the 7/8" thick bar of S-7 (used because that's what I had).
Not having a countersink bigger than 1/2", I looked around in the drill drawer and spied a unibit. Wouldn't do if I needed a full countersink, but worked great to de-burr and chamfer, no chatter at all. Probably old hat to a lot of you, but I thought it was neat.
Pete Keillor