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Old 02-14-2013, 06:50 AM
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Fab question

Does anyone have experience cutting and welding a frame? I'm wanting to to shorten a long bed frame to a short bed and also raise the axle humps on the frame. I'm trying to get more wheel travel and lower the cg of the truck. Any ideas?
 
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Old 02-14-2013, 07:17 AM
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No, ......no idea how to do that. (extreme sarcasm)

Yeah, I can do all of that for you if you want.
 
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Old 02-14-2013, 08:04 AM
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Well thanks for the offer but I was looking more for info on the best way to do it. I work at a steelyard/welding shop and my boss offered to help weld it up and even help with the metal for the cage. I don't really wanna take free metal and run you know. But otherwise I would take you up on your offer. Btw if anyone has cattle they make pretty good equipment in the shop.
 
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Old 02-14-2013, 08:34 AM
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Just use common sense when you do it. There's two ways to shorten the truck. If you want to use a factory short bed, you have to section the frame in two places. Before and after the rear wheels. If you shorten the long bed, you will have what APPEARS to be a short bed, but you only have to section the frame once. Take out 12" of frame in front of the rear wheels. There's a straight section of frame that's easy to shorten. Measure. Mark your cut. Measure again. Measure a third time. Remark your cut. Measure one last time. Cut your truck in half. Take out the 12" section. Mate up the two halves and weld back together. Plate one side or the other. (or both sides) make the bed fit the new frame.

As far as "C-notching" the frame. Weld in some braces to keep the frame spacing. Cut ONE SIDE at a time. Weld in the modified frame arches. Plate both sides. Modify the bed for the larger arches.

It sounds easy, but it's time consuming and involved. It's really easy to come up with scrap metal where you had a good frame if you're not careful.

Spend AT LEAST 2 HOURS measuring before you cut and as you tack stuff together before you finish weld everything.
 
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Old 02-14-2013, 10:17 AM
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Well Im going to use some fiberglass prerunner style bedsides from autofab. So I think I can get by with one cut. I have been told to never make the cut vertical but at an angle with an opposite angle on the other rail to make it stronger. Is this true? I have built my own rollcages before so I can fab some stuff im just a little wary about cutting the frame.

I need the strongest set up possible cause it will live a pretty rough life. Think tough truck, short course offroad or prerunner type of use.
 
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Old 02-14-2013, 10:26 AM
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Not trying to put you down, just saying listen to Alan. He's done this before. Experience counts. Read about the '66 he built. He cut two frames in half & welded them back together for that.
 
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Old 02-14-2013, 10:44 AM
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I meant no disrespect. Tone doesn't carry well on a forum. I was simply trying to ask the question if it mattered if the cut was vertical or at an angle. Believe me I was not trying to offend anyone just trying to gain some more info. If I didn't think he knew what he was doing I wouldn't have responded back. I'm just trying to make the least amount of mistakes cause mistakes cost money. I just didn't know if I needed to do anything more because of the way it will be used.
 
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Old 02-14-2013, 12:29 PM
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Yes, make the joint as strong as you possibly can. Vertical, horizontal, it just depends on how you do it. The key is you want as much overlap as possible. You never want an area where there's a straight line of welds. The opposite angle thing works ok if that's all you plan to do. ...and run on nice paved streets. It'll be strong enough. For your application, you can't have too much bracing. I would cut a clean, vertical line in the frame so it'll be easier to fit back together, since this will be your first time. Now that you have the frame cut and welded back together, brace the hell out of it.

A 3/16" plate that goes 12" on either side of the weld on the inside AND outside. Will go a long way to keep the frame from flexing. I would also invest the time to box in that section of frame as well. When you're all done, the splice should be stronger than the original frame if you do it like that.

Do whatever you can to get the cleanest welds possible. MIG or TIG are preferable. Arc welding won't cut it here.
 
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Old 02-14-2013, 07:29 PM
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On the show "Trucks" they shortened the frame and bed of a 65 ( I think it was) Chevy. I'd google it if I were you. They have videos of all their shows and it'll show you exactly what to do.
 
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Old 02-14-2013, 07:58 PM
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Thanks for the help guys. I finally found the thread on the 66 looked great and looks like it would be durable. I will try and google "Trucks" and check it out too. It just sucks only having internet on my phone or at the college takes forever to do anything.
 
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Old 02-16-2013, 06:31 PM
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I believe a "fish plate" (google it) will work here or even a Z cut, correct no straight line cut/reweld will hold up.

 
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Old 02-16-2013, 09:18 PM
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The z cut is what I had been told to use before. I like that fish plate but I would def need some practice been attempting that one.
 
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Old 02-16-2013, 10:40 PM
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That pic was a quick internet pic to at least have a pic to go with the suggestion.

Alan really has his head on right when it comes to things like the level of fabbing.

I'd get him to help me if I have a project like that, hay the reminds me I just might have one like that some day? Penny's Rock-Ford is way to long in the back end....
 
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Old 02-17-2013, 08:31 AM
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No problem Rich, just let me know when you want to do it. I think I owe you favor or three after the "Great Wrecker Relocation".
 
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Old 02-17-2013, 09:16 AM
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I know you will lend a hand, I am sure that project will always be just a project or pipe dream.

I might just sale all the components one day? Thanks for offering to help, I appreciate it.
 


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