Frame stretch

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We have a 72' 4 door international pickup truck in the shop that is to be stretched by 5'.  Most of the guys in the shop have stretched vehicles in their past but go about it different that one another when it comes to the splice.  The picture is of a style a guy used on a limo frame.  How do you go about it? Attached ImagesCommon sense in an uncommon degree is what the world calls wisdom.
Reply:Well, I really don't think 7.00 inch tall C-channel is a big enough section for a 72' long frame.      I'd say to first double-check local/state DOT regs.  Sometimes they call out what is allowed or required.Next, general proportions on the fish-plate don't look big/long enough.  You want that plate to reach out waaaaay past where the actual splice is.I'd also say to really radius the fish-plate corners.  Actual corners are -always- Bad.  Make it rounded and smoooooth so that the stresses and strains can be smooth as well (no added stress risers, the weld itself is bad enough from that standpoint).  The best laid schemes ... Gang oft agley ...
Reply:I match the existing frame rails do a cut like what you have shown. For the fish plate I usually bolt them, and the plate being 20% longer than the splice.
Reply:Personally i like to se a little longer liner thats formed C section and bolted vs. welded.Vantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:Pretty close to what everyone else said.  I do an angled cut vs the stepped cut you have shown.  Formed C-channel sleeve bolted in, and extending past the splice a good 2 to 3 feet either direction.I don't usually do pickups, but Class 8 Trucks are easy - Most manufacturers offer "Frame Inserts" that fit nicely.Later,Jason
Reply:Originally Posted by Black WolfPretty close to what everyone else said.  I do an angled cut vs the stepped cut you have shown.  Formed C-channel sleeve bolted in, and extending past the splice a good 2 to 3 feet either direction.I don't usually do pickups, but Class 8 Trucks are easy - Most manufacturers offer "Frame Inserts" that fit nicely.
Reply:Originally Posted by Black WolfPretty close to what everyone else said.  I do an angled cut vs the stepped cut you have shown.  Formed C-channel sleeve bolted in, and extending past the splice a good 2 to 3 feet either direction.I don't usually do pickups, but Class 8 Trucks are easy - Most manufacturers offer "Frame Inserts" that fit nicely.
Reply:class 8, think 18 wheel over the road tractor Like Ice road truckers.
Reply:commercial class 6, 7, and 8 trucks, are rated according to maximum allowed axle loadings.    Throwing a bunch of play-toys in the mix, doesn't change anything.
Reply:Originally Posted by DualiePersonally i like to se a little longer liner thats formed C section and bolted vs. welded.
Reply:I have done a few semis, 60/30 slanted cut, bolted c-channel over top, 1" holes.The way you have it their you are likely to put stress on the top of c-channel, start cracking.