Ok so we have new off the lathe crank drilling guides . For 5/16 - 24 or 18 . They are a 3 piece tool you start with the smaller hole one a 9/32 bit , and the body . Put on the end of the crank and it guilds the bit on center. Then you switch out the bushing to the larger one and run the tap in and it starts the tap on center and straight .