Drilling a new pattern

[pishta]

Drilling a new 5 on 4 pattern in a set of Chevy Centerlines. Looks to be a .70x hole as drilled and the shank lug nuts are .685 shank diameter. What drill bit size to use, very close to the .70x (like a 45/64 or something or even an 18mm) or should I give myself a little room as the rim is hubcentric with a snug adapter I made on my lathe. Took me an hour, im no machinist and all the guy had were 1/4 inch HSS cutters! Or could I go easy and just drill a 60 degree countersink and use regular lug nuts?

[pishta]

Well, duh. It is an 11/16 drill bit to get you a .6875 lug nut hole that fits a .680 shank lug nut. I drilled a set of Chevy Centerlines and by golly it worked. Used the drum and a centering jig I lathed as a pattern and used a precision ring between the Chevy rim centerbore and the Mopar hub. Worked like a charm, so start buying those crusty Chevy centerline's and drill a new SBP Mopar into them! Would like to do up a set of Cragar Supertricks, but all I have seen are dual pattern, no place for a new hole!

[dust]

pictures????

[pishta]

stand by...

[pishta]

Well here are some pictures I found. You need to make an adaptor ring to center the rim on the hub to get an exact center. As for actually drilling the pattern, I found out the hard way that the easiest way to get a correct pattern is to use a front drum hub with the studs pressed out (youll have to use longer stud anyway, at least 1 inch longer than stock to clear the thicker rim center and get a lug that is NHRA legallength) and use a DEEP drill press or mill to drill through the hub. Drill all 5, then flip over the rim and clamp it down. Use the same drill and X/Y the mill table to get the drill exactly through an existing hole. Chuck an 11/16 bit without moving the table and drill your new lug hole. You will pass through the centerbore but I done believe this to be a problem as I have seen factory Slotted mags in the 5 on 4 pattern that have the holes come through the center bore. Better yet, get a reduced shank diameter lug nut and drill a smaller final lug hole if that makes you feel better. The measurements of the center adapter are 2.308 ID and 3.1715 OD. The OD went to the .xxxx so it would be a snug fit. Mine slipped in but would not wobble it was so close in tolerance. I would rather have an interference fit. The ID was taken off the center register of a 10" A body drum hub, the smooth part. The ring needs to be about 1/2 tall so as to make contact with both hub and rim center. I used a lathe and a dial mic to get the measurements and made it out of brass to make it easier, but Aluminum or steel would work as well. The lug nut shoulder keeps the ring captive. I could not find any of the aftermarket adapters mentioned so I made my own. Good luck