My old master would nail me to a cross with rusty shaper bits if he could read this.. However I'm sure he has long gone to that happy place where the days are long, the temperature in the workshop is perfect, the electricity is free, the cutting oil always smells sweet, and there are NO NAGGING WIVES..!! Anyway.. I've found an easy way to cut those seats for nut and tail cone fittings.. A standard drill is ground at about 59 degrees which is a bit too sharp of an angle. The average cone fitting wants about 68 degrees to seat snugly. If you gently prep the hole with slightly over and under size drill tips, you can then apply a philips head hand drill screwdriver bit to the job. The angle is pretty well perfect. It can be done without prepping the hole too. Admittedly the bit won't as last long.. but they are cheap, and in brass it will last long enough for a good few jobs.. Cheers, Geoff.