Hey everyone. I'm looking to do my own 6 lug conversion. I need to drill the holes so the lug nuts don't spin obviously. Does anyone know what size drill bit I need to buy so the splines on the studs bite into the hubs? 9/16" end wrench will fit over the stud itself, 14mm won't, but I feel like the stud could spin in the hole with that size.

Factory EA82 studs have about a 14.2mm knurl diameter (according to the Dorman listing), new gen Subarus are 14.38 (but the shoulder is too long for EA applications, as the rotor doesn't slip over the studs).

Looks like I used a 35/64 drill bit (13.89mm). I also used Dorman 610378 studs, which have a 14.48mm knurl diameter, smaller head (easier to seat with the curved material on the back of the hub where they need to be), about 10mm longer overall, but short enough shoulder even for steelies (open lug nuts required, though).

Awesome, thank you. I bought a drill press a year ago just for this job.