Cragar stud hole size?

rod · 02-09-2017, 08:56 PM

I have a pair of Cragar S/S rims which are direct drilled for a 5 on 4 3/4 circle using 7/16 studs. I need to drill the studs holes out because I now have 1/2 inch studs and the nuts have a larger OD shank. the shank is .732 and the closest drill is a 47/64th at .734. next is a 3/4 at .750.
my dilemma is this: is .734 to tight or is .750 to loose.
Cragar does not have a phone #, so I cant contact them.
first race is Saturday next. so I need to get this done asap.
thoughts or ideas.
thanks Rod in AZ

Hacksaw · 02-09-2017, 09:05 PM

Can't see .734" working out. Do a test hole, often a drilled hole will be larger than the drill size and make sure your work is secured. Hopefully your not drilling by hand!

Bob Mulry · 02-09-2017, 09:47 PM

Hi,

I think that if you measure the shoulder diameter on the old 7/16" lug nuts you will find that the shoulder diameter is around .680" +/-.........

There are many choices out there for racing shouldered lug nuts with a 1/2-20 thread and a .680" +/- shoulder........

On the other hand I could be completely wrong.......

Bob

rod · 02-12-2017, 12:08 PM

I jumped before I looked. the lugs I have for my 15 x 7 uni-lug Cragars are .742. whereas std Cragar lugs are closer to .680. I did some checking, and as you stated there are 1/2x20 .680 lugs. a friend has 6 boxes of lugs. I found 11 which were .680 with the 7/8 head [which I wanted to match the front]. some were 7/16. I put them in the lathe, milled off the cap on all, drilled and tapped the small ones to 1/2 x 20. now I am happy. [except that it is going to rain in Vegas Sat. next-ugh]
thanks for the help.
Rod in AZ

02-09-2017, 08:56 PM	#1
rod Member Join Date: Dec 2009 Location: Kingman, NW AZ. in the middle of the longest stretch of Route 66 Posts: 313 Likes: 0 Liked 20 Times in 15 Posts	Cragar stud hole size? I have a pair of Cragar S/S rims which are direct drilled for a 5 on 4 3/4 circle using 7/16 studs. I need to drill the studs holes out because I now have 1/2 inch studs and the nuts have a larger OD shank. the shank is .732 and the closest drill is a 47/64th at .734. next is a 3/4 at .750. my dilemma is this: is .734 to tight or is .750 to loose. Cragar does not have a phone #, so I cant contact them. first race is Saturday next. so I need to get this done asap. thoughts or ideas. thanks Rod in AZ

02-09-2017, 09:05 PM	#2
Hacksaw Senior Member Join Date: Sep 2016 Posts: 875 Likes: 192 Liked 300 Times in 168 Posts	Re: Cragar stud hole size? Can't see .734" working out. Do a test hole, often a drilled hole will be larger than the drill size and make sure your work is secured. Hopefully your not drilling by hand!

02-09-2017, 09:47 PM	#3
Bob Mulry VIP Member Join Date: Apr 2002 Location: Coarsegold, CA Posts: 1,016 Likes: 57 Liked 319 Times in 101 Posts	Re: Cragar stud hole size? Hi, I think that if you measure the shoulder diameter on the old 7/16" lug nuts you will find that the shoulder diameter is around .680" +/-......... There are many choices out there for racing shouldered lug nuts with a 1/2-20 thread and a .680" +/- shoulder........ On the other hand I could be completely wrong....... Bob __________________ Bob Mulry 7516 STK A & M Motorsports

02-12-2017, 12:08 PM	#4
rod Member Join Date: Dec 2009 Location: Kingman, NW AZ. in the middle of the longest stretch of Route 66 Posts: 313 Likes: 0 Liked 20 Times in 15 Posts	Re: Cragar stud hole size? I jumped before I looked. the lugs I have for my 15 x 7 uni-lug Cragars are .742. whereas std Cragar lugs are closer to .680. I did some checking, and as you stated there are 1/2x20 .680 lugs. a friend has 6 boxes of lugs. I found 11 which were .680 with the 7/8 head [which I wanted to match the front]. some were 7/16. I put them in the lathe, milled off the cap on all, drilled and tapped the small ones to 1/2 x 20. now I am happy. [except that it is going to rain in Vegas Sat. next-ugh] thanks for the help. Rod in AZ