The CueTec pin is a 9mm x 14 and NOT A 3/8 x 14 as stated. Use of a 3/8 x 14 tap, as Dick stated, will cause an excessively loose fit. A low cost work-around is to grind the 3/8 tap down to .356". Wax the tap before use and tap the hole in two passes. Half tap length in the first pass, full tap length on the second pass. Black linen phenolic makes an excellent insert as you will be incorporating the bottom ring into the insert as a single unit. Any more questions, just ask.