roll cages

[turtle]

andy i am concerned about making a chrome moly roll cage for my friends 4x4 the cage would have to be still welded inside of the cab of his truck and if cromally has to be tig welded how is that going to be possible when i have limited clearance and wont be able to weld completly around the tubing since i will be hitting the torch on the inside of the cab? do you have any suggestions how people have done this before? i keep telling my buddy i want to make the roll cage out of schedule 40 pipe 1 1/4 since i can arc weld and bend my rod around to get in the tight spots that a tig torch wont get into,also how is the strength ratio of a arc welded pipe compared to a chrome moly tubing tig welded, also is chrome moly measured in pipe-id or in tubing-od ? any information on how to make interior safety roll cages or any web sites that can help me out in this fabrication would be greatly appreciated . living out here in hawaii we dont carry tubing or chrone moly it all has to be special ordered and shipped in and cost an arm and a leg, so i would much rather use pipe since it is readily available and will be buying a bender with dies to bend pipe.

[ROCK]

HI TURTLE......... Well I think I would go with the chrome-moly. Even if it goes for an arm-and a leg........ I'm going to reference another web site here per your request it is www.hobartwelders.com We have discussed roll cages many times on the above website........ Many tips on fabricateing and welding....... As a further aid I will also tell you that Miller/Hobart are both owned by the same company and it is Illinois Tool Works "ITW" and we work quite well together........Regards...........and welcome aboard.....Rock...
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[Gusmann]

The best way I've found to weld the top side of a cage is to drill holes in the floor big enough to drop the cage through, set the cage up on plates over the holes, tack the cage together, pull the plates and drop the cage through the floor, weld the top side, complete the welds, pull the cage back up, set the plates under the cage, and weld the cage to the plates and the plates to the floor. This a great technique for uni-body cars. On framed cars or trucks where the bar is tied to the frame, you may need to loosen/lift the body from the frame to get enough clearance to weld the top.

Are you doing this "just in case" or is it required by some sanctioning body? Get a rule book if it is the second case. If not, I'd suggest you get the NHRA rule book and follow their reccomendations for tubing size and construction. They do not allow arc (stick)welding of roll bars. They require MIG or TIG for mild steel and TIG for chrome molly. They allow chrome molly to be thinner and smaller OD. If I recall correctly chrome molly is about 1/2 the weight of a similar steel cage.