Cage questions

[daniel_buck]

Time to upgrade the cage a bit on my TJ. I've got a few rock-hard bolt on pieces right now, but I really don't like them, some of the threads are already stripped, and now that I have 220 power and alot more welding experience under my belt, I feel confident enough to weld some cage pieces. I always knew the rock-hard pieces would be temporary, finally time to remove them. Since the threads on several of the rock-hard joints them are messed up a bit, I'll probably just cut the ends off and use the tubing as practice joints, or gussets.

I'm going to replace everything accept for the factory B pillar, since that's where everything mounts, I'd like to leave that piece intact. I've got Poly/Synergy A-pillars on order, because I'm not confident enough with bending to get that angle perfect for the soft top to mount correctly. For my long drives across the US, I'd like the soft top to still mount pretty good, I usually go through a good bit of rain on those trips. The rest of the cage will be mostly straight pieces with minor bends here and there.


For the C pillar, I'm going to make it a 'fast back' CJ style c pillars, with little or no bends in them. I've determined that I am rarely ever going to have anyone in the back seat, and never while wheeling. Simpler, less tubing, less bending, and I like how they look better too. Soft top should still work with it, since it's only attached at the B pillar and A-pillar header bars. Also going to put a harness bar and probably an X brace on the B pillar. Harness will be there for driver and passenger, but I will also leave the factory seatbelt in there (if I can) for street driving.

This will probably be a slow-burn project, as soon as I get the willys back on the road, I'll put the TJ under the knife.

For the seats, I'll probably pick up a set from Twisted Stitch, I love the twisted stitch seats in my Willys.




So my questions are about tieing into the frame.

As it is with the Synergy/Poly setup, the only piece that would be tied to the frame are the A pillars. Would this be bad to have only the A pillar tied? I know the frame and body flex independent of each other a little bit (rubber bushings). Would it be best to try and tie the B and C pillars to the frame as well? I assume that the bushing on most frame-tie-ins is for this purpose, to keep a bit of flex there? It looks like there's room to easilly tie the C pillar to the frame, but I'm not sure about the B-pillar.

If all the pillars are tied to the frame, it would be best to mount the seats to the cage, instead of the tub floor? Or for slow rock crawling does this not really matter so much to have the seats mounted to the cage?

[4xfiend]

I am also planning on doing this soon (also a fastback style.) From what I've researched, the bushing on the frame tie in is for the movement. You want the bushing on the body side, not the frame side. Tie the seats into the frame. If something catastrophic does happen you want to stay with the cage, not be thrown around inside it.

[Tumbleweed13]

I think seats mounted to the cage, would be overkill. If your seats are on sliders, and recline, they will move in a high speed impact, anyway. To the tub is good. It has already passed DOT safety standards as it is.

Tying the cage to the frame, is the difference between, your cage and tub being able to be used again, after a severe roll, or not. When not tied in. the cage can tear the tub and move more. This has less of a chance of happening when it's tied in. Minor flops, it wont matter.

To help make your soft top fit. Look into the Poison Spyder Heavy Duty A to B pillar spreader bars. They are .120 DOM, I believe, and they are ready to accept the factory soft top.

http://shop.poisonspyder.com/TJ-LJ-H.../14-18-030.htm

[daniel_buck]

Sounds like tieing to the frame won't be a bad thing, so long as bushings are used under the body. I'll see if I can do that on as many pilars as possible. A and C look easy, B, I'll have to think about a bit.

Not sure what I want to do for the seats just yet. I love the "Apex" seats from Twisted Stitch in my Willys jeep, I'll have to measure them and see how they will fit in my TJ, I like to have a center console in the TJ, they may be to wide for that, not sure. I'll have to think about mounting them. It might be fun to make some bars to mount them into the cage. I already have a square tubing die for my bender in two radiuses, square tubing would probably be very easy to mount seats to. I could easily bend the tubing to get over the transmission hump I think. I don't think I'll have the seats on sliders, and the Apex seats that I like don't recline, they are a bucket.

I'll have to think more about the seats and the B pillar tie-in after I get the rest of the body mounts welded in, and the rear shocks outboarded, those are next up on the list, just waiting for some free time to do them. If I can stop working on my friend's jeeps for a few weekends, I can knock them out

[4xfiend]

When not tied in. the cage can tear the tub and move more. This has less of a chance of happening when it's tied in.

This is the reason I've always read to tie the seats to the cage. If there were separation, where would you rather have your seat? With the cage, or the tub? Granted, it would be a pretty catastrophic roll but, if you're building custom, why not do it?

As for sliders, I've always thought THESE were pretty badass.

[RAT]

When the roll cage is connected to the frame it will flex with the frame so be ready for that. The body will move one way and the cage another. Neither bad nor good, just pointing it out. Plus wherever the cage penetrates the tub a good quality sealer should be used. If you are using sandwich plates at the floor penetrations, make sure to use grade 8 bolts, and again, a good quality sealer to keep dirt and water out of the tub. I like the seats mounted to the cage. For reasons already stated. Again, if you do that be ready to experience more road vibration. Good seats will mitigate this.

[daniel_buck]

Thanks Kurt I have a feeling I'll be calling you with a few more questions as soon as I get started Yes, sandwich plates is what I'm going to do. I guess if there's room for larger plates, the bigger the better, right?

[RAT]

Thanks Kurt I have a feeling I'll be calling you with a few more questions as soon as I get started Yes, sandwich plates is what I'm going to do. I guess if there's room for larger plates, the bigger the better, right?

4x4 is plenty.

[daniel_buck]

I've got some DOM 1 3/4" tube that I'm going to make some practice joints with (my old bolt on 'cage', hah!), I'm going to try my hardest to make the welds look good, nice and steady. I've got the heat I need now with 220 power, so I'm not worried about penetration. I'll probably run 03 or 035 wire, and I'll run several test joints on the tubing before I actually burn anything on the jeep to dial in the settings and to refine my hand movements to curve around the tubing.

Any tips for welding a roll cage? Do you do 4 tacks per joint, top, bottom, and sides? or just 3? Connect the tacks, or start in between the tacks and weld over them? I've done alot of square tubing, and alot of flat sheet metal and plate, but not much round tubing.

I do have a tubing notcher, from JD2, hopefully I can get the fitups pretty tight.

[Tumbleweed13]

I don't know, what type of research you've done on tube notching. It is a skill, all on its own. One of the fastest ways to waste material, is to make 1 wrong cut. With 1.75" tube, any notch 28* or less, is a snap. Anything beyond that, gets tricky. I would highly recommend you read the following article. A lot of it didn't make sense to me, till i started working with the tube, but then it all becomes crystal clear. Knowledge is confidence.

The notching info, is about 2/3, into the article.
http://www.pirate4x4.com/tech/billavista/Links/

If you look thru the other Tech articles. There's one on seat belt mounting. It may help with your other question.

[daniel_buck]

yep, I've been reading through them as well as the various roll cage threads on various forums.

Worst case, I waste a bunch of tubing, then come running to Kurt haha! I'd like to try it myself though. I think it would be fun.

[6spdYJ]

There are sliding pin do-hickeys that copy the surface you are trying to match so you can do your shaping on the bench and not have to wrestle tubing. There are straight line versions as well that are used in tile work that can be found at any home improvement store.

[daniel_buck]

yea, i've seen those! I bet they are a good thing to have.

I kinda want to TIG weld the cage, because i think if I do it well enough it will look awesome. But I don't have much tig experience, so I think I'm gonna shop up a bunch of tubing and start practicing. Maybe I can get it down good enough to try and tig it. If not, I'll mig weld it. I'm pretty confident with the MIG welding after a few years now.

[Tumbleweed13]

The sliding pin, do-hickeys.
http://www.pipemastertools.com

[daniel_buck]

Ok, it's getting time to start this I hope! If all goes well, I'll have a week or two off from work, my goal is to at least get the C pillar taken care of. I'm gonna see if I can just use straight tubes. The seats will eventually be mounted about 2 inches lower, and about an inch farther forward.

I MAY need to put a bit of a bend in the tubes for a bit more protection above the head? I'll need to sit in there and take some measurements.

I don't see a good way to tie the C pillar into the frame though. On the driver side there's the filler neck and vent tubes and such, and on the passenger side there's the charcoal canister. If just the A and B were tied to the frame, would the C only mounted to the body be a problem?

There will also be a horizontal tube going from the B to the C pillar running just below the top edge of the tub, not visible in these photochops.

Here's what I'm thinking for the C pillar: