I have a heap of small holes to tap shortly and I want them to be firstly straight, and secondly I dont want too many (nil!) broken taps. I therefore needed a piloted tap driver!
Almost all my holes are 4 BA so Ive built this around that particular size. I will make a few more in common sizes though...
The unit itself is quite simple BUT... I had my first attempt at knurling, and while not perfect, Im pretty impressed with the result...
Pilotted Tapping Tool
Pilotted Tapping ToolI might just go and knurl something else.....

P.s. that a 4 BA die next to it for reference... centre shaft is 12mm.