drill bit size for gm wheel studs?

[Nskeeter99]

in the middle of a disk brake conversion on my amc 20. I got a set of rotors for a 75 Chevy 4x4, was going to just sick the behind the flange and pin them with the wheel studs like they were don't on the Chevy front. so i picked up 12 wheel studs for a 75 Chevy 4x4. they are a good bit bigger, and my bit sizes are 1/2, 9/16ths and they are some were in the middle. I hoping some one knows off the top of there heads what size bit i need?

Skeeter

[HAPPYJOHN]

Per NAPA website, the knurl on the stud measures .565", so
I would drill just under that. probably start just under 1/2",
you want it to be a tight, "press" fit.