School Me on Stretching a Frame

[MSGGrunt]

Title says it all. Is there a right and wrong way to stretch a frame? I need to add 10" to a 62 series frame. I am not a welder and do know that I will have it welded by a professional.

I guess the big question is, how to cut the frame? Just a straight cut vertical 90 degrees to the top rail or a stepped cut like in the pic I stole with a matching 10" section welded in?

 

[Bret]

I wouldn't just cut straight down, I believe you want at least twice the weld length as the frame height. So if the frame is 4" tall you want at least 8" of seam to weld. I would check with the person you are going to have weld it, they may have some liability concerns.

 

[D'Animal]

Hire it done by a reputable welder/fabricator.

 

[Medusa]

1) Cut

2) Insert extension

3) Weld

4) Weld sleeve

 

[yotawheeler]

Hire it done by a reputable welder/fabricator.

I would be amazed if you could find a proper welder/fabricator who will touch it....too much liability involved in doing that kind of thing. BUT if you can find one who will do it defanitly call him and ask him how he wants it done, of even take the frame in as is and let him cut it the way he wants...

 

[D'Animal]

If I would do a frame stretch, Don at FC Fabrication would do it.

If I was closer, Medusa could do it.

 

[MSGGrunt]

This is just what I was looking for. So, either cut at an angle or like in the pic I posted. I was already planning on plating across the extension.

 

[TURNMEOVER]

after the cut of my frame shown in the pic above. I should have done a angle cut. unless the frame has no taper. then step cut. be sure not to leave any points in your fish plate in order to relieve the stress on the corners.(not sure why but a buddy who is an auto engineer told me so). good luck. it was a butt ton of work. I hope it was worth it.

 

[GarageRat]

be sure not to leave any points in your fish plate in order to relieve the stress on the corners.(not sure why but a buddy who is an auto engineer told me so).

has to do with stress distribution, points concentrate stress which leads to failure.

 

[TURNMEOVER]

sound like something he said. Damn smart people.

 

[MSGGrunt]

I too hope it is all worth it. It will be a fun, time consuming and money consuming project. I'll be mounting a FZJ79 body I bought from Proffitt's Cruisers onto a stretched 60 or 62 series frame. The frame has to be lengthened 10" to make the body fit. I'm just trying to gain some information on how to cut the frame. Thanks for all the info.

 

[D'Animal]

https://forum.ih8mud.com/70-series-tech/140292-new-2007-fzj79-4500efi-inline-6-a.html

Just looking at the pics but 10" added to an FJ 60 frame is alot. I stretched my FJ60 wheel base by 14" and now I'm at 122 inches. (Front axle got moved a smidge as well.) The FZJ79 does not look like it is 118" wheelbase.

 

[MSGGrunt]

Per Grease Cruiser from his putting a FZJ79 onto a FJ62 frame and still maintaining the 7' bed.

I still need 10" of extra wheelbase in order to run the full size 79 bed. I could cut the front of the bed and have a 6' bed instead of a 7' bed. But....I want the full size bed. I will be extending the frame 10" here in a few days.

 

[MSGGrunt]

This is what I plan on ending up with... I will talk with Proffitt's as I get closer to make sure the frame stretch of 10" is correct for the 79 series body to fit onto the 60/62 series frame and keep the 7' bed.

 

[Dieseler]

Just curious do you need to stretch it 10" from the middle to make it work or just add to the rear of the frame it looks like the 7' box has more over hang than stretch from cab to axle.
Could you not get away with reversing your springs and going with a longer spring to gain the little extra needed on the axles to line up with the wheel wells I am looking at my 62 and the pics while typing this and it looks like you would only be out by a 6" at most
Have you tried a dry fit on the 60 frame to see where you are at with your measurements with body and box to referrence your axle placement.

 

[MSGGrunt]

Again, below is from someone that is doing the build now. I do not have the body yet or the frame to sit it on, but I am working on both.

Suspension: 2" OME FJ60 front springs. Rear springs are factory HZJ79 springs that have 3 (YES 3) overload springs removed. There is still a 7 leaf main pack and one overload. I am going to try this setup for awhile and adjust if I need to. The 79 springs are VERY LONG. I used the factory 62 spring hanger in the factory location. I had to move the rear shackle hanger back 8.5" which moved the rear axle back 8.5" The rear still sits high.

 

[D'Animal]

I'm not understanding something.

If you use the HZJ79 springs you already have to move the rear hanger back 8.5". This moves your rear axle back 8.5".

You can flip you front springs and get about 2" so now you would be at 10.5" longer between the axles than stock. You need an additional 10" on top of that?

 

[Dieseler]

I'm not understanding something.

If you use the HZJ79 springs you already have to move the rear hanger back 8.5". This moves your rear axle back 8.5".

You can flip you front springs and get about 2" so now you would be at 10.5" longer between the axles than stock. You need an additional 10" on top of that?

My exact thoughts you should be right on the money when you drop the body and box down on it... you might be to far back and have to move the axles up a bit.
Do a dry fit before you start chopping up the frame (weigh on the side of caution):whoops:

 

[kcustom73]

I stretched my 40 frame 27" last year. Got a fabricator to do the work for me. He did just a butt weld but we completely redid the internal bracing with 3/16" steel. Guy did some really nice work. Might add little more metal to make it stronger but I think the way we did should be strong enough to give me the DD/expedition rig that I want. Take a look at post #26 of my build thread for some pics.

https://forum.ih8mud.com/40-55-series-tech/182303-my-75-fj40-build-up-thread-2.html

 

[bjowett]

The greatest loads are at the top and bottom of the rail, so I would think that is where you want the longest welds.