Question for experienced welders. I have a 1997 f350 reg cab 4x4. Going to be cutting the last 2 feet off the rear frame rails cause it's beyond repair rotted. (Previous owner had a boat). Rest of the frame it's very clean. Anyways I got a donor frame from approx the cab back. So I talked to a guy my old man workers with wich is a welder and he said we should cut it like a "z" and weld it, along with brackets inside the frame rails and grade 8 bolts. I have minimal experience welding so I'd like everyone's input. I'll post a pic of what he drew. Thanks in advance

 

 

that would be the strongest way to cut/weld and then fishplate the frame.

 

Yes. Cut it sort of like that. You want one foot of weld minimum. You see those sharp 90 degree edges? Don't do those. They're bad. Take a roll of electrical tape or something round and use it to radius the 90 into a nice sweep. No stress risers that one.

Once you get that welded up you want to plate it. DO NOT make rectangular or square plates. Those are bad. Once again sharp 90 degree turns. You need what're called "fish plates. Think of a diamond. Once you cut out the diamond once again use the roll of tape to radius off the ends for no sharp corners.

Use plate that is either the same thickness as the frame or the very very next size up. If a frame is 1/4" and you plate it with 1/2" plate thats way too thick and stiff. You want it to flex at the same rate the parent metal flexes at or else it will crack again.

 

Should I bolt or weld the "fish plates" in? Or both bolt and welt the plates

 

the fish plates get welded over the repairs.

 

Oh okay so weld from inside the frame rail not the outside? Then fishplate over the inside weld and weld it there

 

No. Weld it all the way around. Once you get both frames lined up and squared up tack it together, recheck to make sure it's still all square and true, then fully weld it. Both sides. Weld everywhere you possibly can along where the two pieces meet.

After you do that you can grind it down if you want/need to. If you're good at welding you won't have any gooberness, but if you do grind it down so the fish plates will sit flush.

When I build fishplates I'm overly picky and tend to tack them all together as one then use my belt grinder on them to round them off and clean them up and when I'm done I have fishplates that are identical to eachother.

Put one fishplate on the outside of the frame rail, and one of the inside. After that you'll be beyond golden.

 

My phones being dumb at the moment but go on YouTube and look up "shortening a frame Stacey David". He has some videos on doing it the right way and explains it. You need to watch like three or four five minute videos though as they're all seperate for some reason.

You live pretty close to me if you end up needing some help.

 

Okay thanks where do you live buddy?

 

New Milford, CT. About 3 1/2 hours from cape cod.

You might not consider it close, but I'm pretty used to driving. Haha

 

Yea that's not bad! I'd say I'll pay yea and buy the beer 🍻

 

im 20mins away so ill just take the beer offer...
still looking for that bed for you.

 

Haha if you find me a bed a case of beer of your choice for sure

 

I was going to ask for pizza and wings.