There have been a couple of posts about this. This is my way of doing it. The bolt is simply screwed in the back of the "bucket" then placed in a collet in the Lathe. Large bits are cut off with a hacksaw, small amounts are simply turned away. The Lathe is put in reverse and the side of an insert or tangential tool forms the chamfer - perfect every time. I use a lock nut or washers for length adjustment. Sizes shown are M3, M4, M5 and M6.