To ream out the endpin hole for a pickup's strapjack, Stewmac provide a nifty two-step reamer for hand or power use. This machined steel reamer is made specifically for enlarging a guitar endpin hole to accept a 15/32" or 1/2"-diameter endpin jack. It won't chip the finish, and it's semi-fluted to help keep the hole round. The 3/8" shank can be chucked in a hand drill for slow reaming. The upper 1" cutting length is 1/2" diameter; the 1" centre section is 15/32" diameter, and the lower 2-5/8" section has a standard 5-degree endpin taper to 1/4".