What size hole/drill bit do I need for a stud????

By jwright650 (*****)

Date 07-10-2007 17:14

I found a rule of thumb stating "to use a drill size of .008-.010" smaller than the knurl size"

By Greg G. (**)

Date 07-12-2007 14:25

Is this a press in stud, say like a 1/4-20 stud from PEM. If so let me know and I will look it up in a book that I have that has all that information.

By jwright650 (*****)

Date 07-12-2007 14:42

No, it is an automotive application. Wheel studs are 7/16 press in studs presently at the rear axles and 12mm at the front hubs, and both will be drilled out to accept 1/2" x 20 x 3" long press in studs. I found a 1/2" stud that has a smaller knurl(.564"), so I won't have so much material to take out.

By Greg G. (**)

Date 07-12-2007 14:45

Then the .008-.010 should be good for your application. Might even go on the small side of that to be sure.

By Sourdough (****)

Date 07-12-2007 17:28

You got me.........Git er done.....

By waynekoe (**)

Date 07-12-2007 20:34

I;m thinkin' warm up the drum and throw the studs into the freezer, this should give enough clearence and be a tight fit after you press them in.

By DaveBoyer (*****)

Date 07-13-2007 05:15 Edited 07-13-2007 05:26

The .008-.010" should work OK. The knurled part will work into a smaller hole than a round stud, as the grooves give the extra material some place to go. Steel expands as about 6.4 microinch [0.000064] per inch per degree. freezing a stud this size won't change it measurably. Heating the axel flange is risky buisiness, there is no need and little to be gained. If there is an un knurled area [the diameter that the stud was before knurled] this should be a slip fit in the hole. I suggest You try a test piece with the same size pilot hole as the flange to be sure You are getting the size You want. 37/64 would give You 1/64 [.0156"] interference, if the drill cut a little oversize You would be in the balpark.