best way to bolt something to a box frame?

[foxracing5491]

im starting this thread to mainly see how people have bolted any bracketry to a boxframe with no access to the inside besides cutting a big hole. ive run into this problem with my panhard bar mount, but solved it with a couple of hrs of finger f***ing one of my old ttb bracket bolts with the cleavis thru a small hole into the frame and thru the bolt hole itself, then nut it from the outside.

 

[PanamaExpat]

Drill through both sides and use a longer bolt...

 

[a31ford]

The Big thing about bolting through both sides of a boxed frame, (like box tubing) is the "crush factor".

Doing it correctly, would require this:

On "side A", hole with the size of the bolt, AND drilling through the other side as well.

On "side B", RE-drilling ONLY this side, to a hole size that would accept a "anti-crush tube".

Anti-crush tube is length of I.D. of box, PLUS the thickness of ONE sidewall, the re-drilled hole should secure the tube as near to tube's O.D. as practical.

Insert bolt from side A, insert tube from side B, use a LARGE, THICK washer to cover tube, Use lock washer, and Nut(s), torque to bolt spec, double nut and torque second nut.

If a "really" tight fit is needed, make tube , a hair short, so it slightly pinches box.

The BIG thing here is that the B side hole should be as tight as can be on the tube......

Oh, BTW, The bolt WILL be tight to the one side (because the crush tube will direct the pressure of the nut through the box and on to the back side of "A", the other side (B) will also act as a "fulcrum" and with a tight fit on the crush tube, will NOT let the bolt "Starburst" the hole on side A.

Greg

OOT (One Other Thing),

I had posted a ton of info on frames in message #9 in the following thread

http://www.therangerstation.com/forums/showthread.php?t=136045

G.

LMAO... second last thing (SLT), NEVER drill the top or bottom of ANY frame rail or box, for ANY reason.

 

[4x4junkie]

What I do is drill a hole sized to fit an anti-crush tube like a31ford mentions through both sides of the frame, except I weld the tube in place on both sides (recessing it slightly on both sides to accept the weld bead). Grind it down smooth if needed, then bolt your bracket, etc. through that. This allows full clamping force of the bolt coupled into both sides of the frame with no crushing or pinching.

 

[a31ford]

If you have a welder , I agree with 4X4, that IS the best way to go. (it is the way I would do it as well), but had no idea if he had access to a welder.

Greg.

 

[PanamaExpat]

Don't most of us have welders? If not you can buy a buzz box for about $100. I didn't go into as much detail as the other guys but I believe you got the answer you were looking for.

 

[foxracing5491]

thanks for the input guys. already solved my problem with my panhard bar bracket as stated earlier. just tryin to help leave some information for others that run into this problem. have also known about the sleeve option, just wasn't a usable option in my case since the engine crossmember/axle mount was directly on the other side. i was thinking more specifically on not using both sides of the frame rail, just the outer side the bracket would be held to.
i have seen where a nut the size of the bolt/threadpitch welded to a thick washer. then hole drilled into the frame the width of the nut, and then weld the nut and washer to the frame with the nut facing in.

 

[foxracing5491]

http://www.jeepforum.com/forum/f9/nutsert-transfer-case-removal-install-390635/
also just found this. i am a motorcycle mechanic and have used small 6-10mm nutserts but never seen any 1/2" ones in person.