On Fri, Feb 24, 2023 at 05:57 PM, Bill in OKC too wrote:
drill to depth with a regular drill and then remove the corners with a flat bottom drill.
I was assured long ago that a flat bottom drill is made from a slightly bigger drill, with the cutting edges ground off the flutes, and the end flattened. Never seen anyone take the trouble, perhaps because there's only one company I've worked with who had a cylindrical grinder.
