Here's another chart that shows decimal to fraction http://www.gearhob.com/eng/design/drill_eng.htm which says a 13/64th bit is .002" larger and may be easier to find. the 2 thou isn't going to make a difference.Originally Posted by Tremelune
BUT you do need to know for sure what the thread pitch on your zerts are. I used 1/4-20 as most likely but I don't have one to measure. Your tap-die set should had a thread pitch gauge in it.
I actually have the correct drill bit for each tap I use taped to it so there's never a question of which bit I need.