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box steel rockers - why leave the pinch weld?

Chris S

NAXJA Forum User
On the write ups I have seen on cutting out your rockers and replacing them with box steel all but one have left the pinch weld seam in place.
The box steel will provide way more rigidity than the pinch weld ever did, so why not cut right back to the floor board seam and weld on there?

Image from MadXJ:

RockerPanelDesign01_sm.gif


:canada:
 
Good thinking Chris, I did my rockers with 2x6x1/4" box tube fully capped and tapped to make airtanks. The box tube is mounted flat with the floor board, and sticks out past the doors to help keep the door bottoms from getting wrecked. It gives you a lot of extra clearance, and done correctly will stiffen the unibody. I used 1/2" plugwelds every 2 1/2" from the inside of the floor to the box steel. I plug welded 1/4" holes every 2 1/2" along the outer door sill along with the whole length of the whole rocker sill. This was done at the same time as I opened the wheel wells. It makes a huge difference in the rigidity of the chassis.
 
I cut mine back to the floor board seam. I wouldn't recommend leaving the pinch seam if you were going to cut that much anyway.
 
93xjmark said:
Good thinking Chris, I did my rockers with 2x6x1/4" box tube fully capped and tapped to make airtanks. The box tube is mounted flat with the floor board, and sticks out past the doors to help keep the door bottoms from getting wrecked. It gives you a lot of extra clearance, and done correctly will stiffen the unibody. I used 1/2" plugwelds every 2 1/2" from the inside of the floor to the box steel. I plug welded 1/4" holes every 2 1/2" along the outer door sill along with the whole length of the whole rocker sill. This was done at the same time as I opened the wheel wells. It makes a huge difference in the rigidity of the chassis.

Slightly confused where your door sill plug welds are.
 
Chris S said:
Quick doodle

RockerPanelDesign02.jpg



PLus I'll put some kind of brace above the box section below the B pillar
I am also getting ready to do this and I have two questions.
First I have heard that the floor boards don't run at the same angle as the rocker...meaning that if you put a flat piece of 2X6 steel up against the floor boards they would stick out more at one end(either the front or rear of the jeep...can't remember which) is this true?
Second what would happen if you used a piece of angle iron on the inside and outside of the floor panel...welde them or bolted them together from the inside to outside then used the outer piece to weld to the 2X6 box section. It seems like this might make it easier to weld together. OR maybe I am just tired and need some sleep. :speepin:
 
A) It's easier because of the angle issued mentioned above and well, it's just SIMPLER that way.

B) Because 6" wide tube will stick it out enough to cover the doors in the event of a rub against something tall and flat, like a tree. Move that 6" stock in where you propose and you'll smash your door every time. ;) After giving mine a few test runs I'm glad I did them the way I did.
 
DrMoab said:
I .....
Second what would happen if you used a piece of angle iron on the inside and outside of the floor panel...welde them or bolted them together from the inside to outside then used the outer piece to weld to the 2X6 box section. It seems like this might make it easier to weld together. OR maybe I am just tired and need some sleep. :speepin:

Good thought. Easy to compensate for different door to floor distances that way.

ECKSJAY - good point about door protection

Rocker03.jpg
 
Anyone have pics of the finished results? Detailed inside and outside/underneath pics would be great. What other areas and in what manner is the 2x6 tied into front to rear (B pillar)? How about tying into a cage? Thanks!
 
fa9149b8.jpg
here are some pics of how i did what you are thining about,
fa9149af.jpg

fa9149b1.jpg

fa9149b5.jpg

fa9149bd.jpg

fa9149d1.jpg

fa8ff469.jpg


the last pic shows the 1/8 in plate that i welded to the body. i welded the plate up first and used a 1in holesaw to cut thru the just the unibody, I welded the sheetmetal to the plate, then I used a 7/8 holesaw to cut thru the plate, using the pilot holes from the first operation, after positioning the 2x6 tube in place, i plug welded the tube to the plate and unibody, I also welded the top of the rocker to the tube and the bottom of the tube to the bottom edge of the plate
 
=raceready....
the last pic shows the 1/8 in plate that i welded to the body. i welded the plate up first and used a 1in holesaw to cut thru the just the unibody, I welded the sheetmetal to the plate, then I used a 7/8 holesaw to cut thru the plate, using the pilot holes from the first operation, after positioning the 2x6 tube in place, i plug welded the tube to the plate and unibody, I also welded the top of the rocker to the tube and the bottom of the tube to the bottom edge of the plate


Did you find that the distance from the floor to the door sill was consistant?
 
THE DOOR GAP IS THE SAME ALL THE WAY ACROSS, HOWEVER THE BODY GETS NARROWER TOWARDS THE FRONT, IF YOU LOOK AT 97+ HEAD ON, YOU WILL SEE THE DIFFERENCE IN WIDTH BY COMParing (damn caps lock) the front flare to the rear flare. the rockers are parallel to each other, but the tube does stick out farther in the front. I think it looks fine that way, as the front and rear axles appear to have the same track width. It also seems that the area under the front door is the most suceptible to damage, and i like having the extra protection there. You will need to notch the tube to clear the seatbelt bolt nutplates make sure you allow for the bolt to stick out into the tube area!), there are 2 of these plates on each side, one in the 4 door location, and one in the 2 door location (1 below the pillar,and one in the middle of the rear door area on a 4 door). I did this so that I could get maximum surface contact between the tube and the rocker.

joel
 
raceready said:
THE DOOR GAP IS THE SAME ALL THE WAY ACROSS, HOWEVER THE BODY GETS NARROWER TOWARDS THE FRONT, IF YOU LOOK AT 97+ HEAD ON, YOU WILL SEE THE DIFFERENCE IN WIDTH BY COMParing (damn caps lock) the front flare to the rear flare. the rockers are parallel to each other, but the tube does stick out farther in the front. I think it looks fine that way, as the front and rear axles appear to have the same track width. It also seems that the area under the front door is the most suceptible to damage, and i like having the extra protection there. You will need to notch the tube to clear the seatbelt bolt nutplates make sure you allow for the bolt to stick out into the tube area!), there are 2 of these plates on each side, one in the 4 door location, and one in the 2 door location (1 below the pillar,and one in the middle of the rear door area on a 4 door). I did this so that I could get maximum surface contact between the tube and the rocker.

joel
I did forget about the seatbelt mounts. good call. I notched the tubing corner, flipped it inside out, and capped it in to make the tanks air tight. I pressure tested them to 300psi with nitrogen overnight to check for leaks.
RockerPanelDesign02.jpg

This pic shows the box tube being 2X5. 2x6 will extend out an extra 7/8" past the doors in the rear, and an extra 1 3/8" in the front. It's kept trees from the doors so far. As far as the 1/4" plug welds, they are located in the slightly angled part of the outermost rocker. I gave that slightly angled part a flattening out and plug welded. then welded the edge the whole length. I didn't use any angle iron.
This winter i will be using these as the base for a full box-tubular mid subframe with long arm mounts and full interior cage with an external roof halo loop.
 
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