Boxed In Frame Rails?

I’ve tried the search function but came up with every post with either “box” or “frame”, even with the quotes around the two together. So…

Is it worth the time, material and effort to box in the rear of an intermediate frame? The front third or so is already done. The bare frame is sitting on sawhorses in my shop, so there’s no better time to do it - if it makes a significant difference, that is.

This isn’t going to be a hard-core crawler or racing Jeep, just an attempt at a solid, capable, off-road (and on) machine.

Jon B.

 

I would. But if you’re going to do any, do it all.

 

waiting for counter points...

I say box it all. The original boxing is very thin... at least on the early stuff.
Then make sure the crossmembers are sturdy.
You might loose some flex so you might need to soften up the springs and shocks.

 

it will collect crud and make rust if not treated properly with some rust proofing.

 

A local fab shop has lots of sheet steel, 10ga. and thicker. I’ll have them cut a few 4” by 60” pieces.

Are there any threads with photos that I can read & view?

Thanks, all for the replies!

Jon B.

 

Most of the boxing posts are buried in build threads. 10ga should be fine try to match your outer frame thickness and i'ld go 4.25 x 60 and weld it outside the channel. I did my frame horns and trying to get the plate set in flush and welded solid was a pain.

 

I used a dimple die on my boxed sections approximately every 12-14 inches. Stitch welded the additions, from the frame horns to the rear including the rear crossmember. Lots of cutting and shaping for the curved sections.

 

This is what I did with my frame. Copied John’s (Posi’s)build. I also ran angle iron inside frame to stiffen it up and am relying on my YJ springs to do the flexing.

 

I picked up a stack of 10ga. metal today, and started fitting to the frame. Steel has gotten expensive! Four pieces, 48” x 4-1/4” for $90!!

I bought four longer pieces several months ago for $69.

Jon B.

 

Ouch!… I need to buy some 1-1/2” tubeing, wonder what that’s gonna set me back.

 

Well if tubing is priced in your area like it is here have them apply a liberal amount of lube before bending you over and inserting it.

 

Yeah I quit buying new steel years ago luckily i come across enough scrap steel to do what I need. I boxed mine in the back up to the crossmember because it was so paper thin and also boxed about 10" where all the spring perches mount. Recently I noticed some buckling behind the gas tank area so boxed all of that area too. It was alot harder with a floor in it the welds on top are questionable to say the least.

 

Boxing thread with some good info.
http://www.earlycj5.com/xf_cj5/index.php?threads/121109/

 

Boxing process thus far:


A plasma cutter would surely be helpful!

Jon B.