I bought a complete drill index all the way to 1/2" from about 1/16" .Then bought drills, starter tap, regular tap, bottom tap kits from Brownells.4-40, 6-32, 6-48, 8-24, 8-32, etc.

Definitely center drills (buy several of each size).

If God wanted you to walk and carry things on your back, He would not have invented stirrups and pack saddles