New truck
#26
07-15-2009, 05:55 PM
If you're planning on stretching in front of the drivers:
Cut the frame at an angle, or V it, or whatever...fab guys have their own ways, but never cut straight down vertical..that's bad.
Then, add your new piece, weld it in place, fishplate the hell out of it, and add a inner sleeve or outer channel "double frame" on the stretched area.
If someone is planning on hauling weight, that's the best approach, along with additional gussets in the bunk area.
Pure show trucks which run around bobtailed all the time are sometimes done differently.
If you're planning on stretching behind the drivers, like for a motorhome, toyhauler, or what have you, the best approach is same as above, although some people just cut the back of the frame at an angle, weld on an extension, and fish plate it without the double channel....
Cut the frame at an angle, or V it, or whatever...fab guys have their own ways, but never cut straight down vertical..that's bad.
Then, add your new piece, weld it in place, fishplate the hell out of it, and add a inner sleeve or outer channel "double frame" on the stretched area.
If someone is planning on hauling weight, that's the best approach, along with additional gussets in the bunk area.
Pure show trucks which run around bobtailed all the time are sometimes done differently.
If you're planning on stretching behind the drivers, like for a motorhome, toyhauler, or what have you, the best approach is same as above, although some people just cut the back of the frame at an angle, weld on an extension, and fish plate it without the double channel....
#27
07-19-2009, 01:21 PM
Diesel Bomber
I'm going to disagree with you here to an extent, lots of people do it this way, but I am NOT a fan of cutting and splicing in a piece. Weld on the back, and redrill with a liner that is bolted in by the suspension as well as the 5th wheel. We have done verticle cuts that haul decent weight (85k avg) with no issues. And some of this was on 1/4 inch rail. Granted its not oilfield, or logging work but still gets stress and strain. Why the additional gussets in the bunk area?? Planning on 140" double eagle??
We cut up vertical 1" from the bottom, then across at a 60 degree angle until 1" from the top and go straight vertical again. It seems to work.
We've done extensions to the rear and slid the axles and bunks back before. It works fine, too and some guys like this method as it requires two main structural weld points.
But then again some guys like avoiding the hassles of removing the entire rear suspension/drivetrain and using the between cab & axle stretch, and I've heard talk of not wanting to stretch @ the rear and slide axles back as that area of the frame is under lots of stress to begin with, and punching new holes for the rear driver, moving the front driver rearwards, and either adding additional welds to seal holes makes for a weaker rail....guess a guy could through bolt the liner with those holes, but like I said before there are many methods people use that work.
Gussets around the bunks are even more important if you're extending the rear of the frame and sliding axles back. Lots of new stress and new weak points at the rear of the frame. I've seen 5th wheel slide mounts tear the tops out of the channels on 105,500 chip trucks.
Lots of ways to do everything.
Last edited by Mr. Miyagi; 07-19-2009 at 01:23 PM.
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