Frame bolts

I took out a couple rivets today to prepare for shortening my wheel base. The hole was about .405-.415" or so, and the same with the rivets (though they possibly did get messed up due to having to be hammered out, I checked more than one spot)

My question is, Do I need to drill everything out larger if I can't find a bolt that size? It's a little under 7/16" (.43), but I can't find any grade 8 bolts in town that size, 3/8" is at .375. Am I correct in thinking that if I use 3/8" bolts that I will have too much play? Granite thats about .02" around the bolt. Anyone know?

Thanks

 

The 3/8 should be fine. You could drill them all out, but I've never done that. I've moved many many spring mounts on 4x4 trucks when building some hardcore wheelers, and even altering wheelbase on 1ton trucks to make them basically a standard pickup length, and never had any issues. If you are not sure, and want to feel better about it, you could drill them all to 7/16 and use that...

Standard machine building clearance for a 3/8(.375) bolt is 25/64(.390) and for 7/16(.4375) bolt it is 29/64(.453)

 

you could get them from mcmaster-carr, or use washers. I'd lean towards running the larger bolt.

 

I would drill em to 1/2"...AKA .500"

 

Thanks guys. I found some 7/16" in town, I'll just drill out the holes a little bit more. Had to get a little longer bolt than I'd probably normally use, but I thought it be a wise idea to have the part actually in the hole, where all the stress would be, thread free. Seems like it would defeat the purpose if crushable threads where in the hole.

 

Torque them down well, and weld the nuts onto the frame on the inside. They won't move that way.

 

Do you think lock washers would do the trick? I want to wait on welding anything till I'm sure what I'm going to do with my rear suspension.

 

Do you have a tapered reamer? Those are pretty good for opening up holes. Do it a little at a time from each side until the bolts slip through. You can mark the reamer with layout die or paint so you know when to stop. 7/16" hardware should be fine.

Bob

 

Right drill bit and bolt should be tighter than a cat's a$$.

 

No need to weld the nuts on...If it is all tightened up it will be just fine.

 

*nevermind figured this question out*

 

use a flanged self locking nut...most HD trucks are held together with them