Brake Rotor Drilling

I’m doing the Brennan metcalf disk brake conversion . The directions say to drill out the rotor wheel stud holes to 39/64 that is a odd ball drill bit size. Can you drill them out to 5/8 which is 40/64 or will that be to loose I’m just trying to not have to buy a expensive drill bit I’ll only use once.

 

I ended up drilling mine out with a 5/8 bit to get around the knurl on the wheel studs. So far the 9 wheel studs are still in good shape. I don't notice anything weird while braking so everything is probably fine. It's been like that for ~500 miles and change.

 

Look for some PM’s from me in the future, as this is on my short list!

 

I drilled mine out to 5/8".

 

You can't put steel back ...

McMaster-Carr

 

I bit the bullet and bought the bit when I did mine. the cost is negligible when you look at the grand scheme of things in life. and you will have it on hand for the next time you do it.