The Stovebolt Site Forums The Shop Area Driveline To shorten a frame or not?

What do you guys think about shortening a frame of a 37 GMC COE from 178 to 136? reason being is I have 2 spots on the frame that's been repaired long ago and they did not do a great job, it will work and has worked but its ugly to see it, and if I cut it out and shorten it , it will take care of the nasty repairs... now I am one of those guys who likes to keep everything like it came from the factory, but in this case I think cutting it and shorten the frame will look nice . the trucks never going to see any heavy loads anymore... I really would like to hear from you guys so what do you think? thank Dan

Just a thought; but is cleaning up the "ugly" and welding a 1/4" thick splint to cover and reinforce the bad area an option? One of my street rod buddies had a similar problem with one of his projects and that approach worked for him. As I recall he made the splint at least six inches longer on each side of the bad spot to make sure he was welding into good metal.

Hy baldybenny, firstly it is your truck and you are entitled to repair it anyway you see fit. Personally I like long wheelbase trucks because you have so many possibilities to turn it into. I used to work with a mechanic who had started out by getting his welding ticket, then decided to get his heavy duty mechanics ticket. He was working at a new truck dealership for awhile and he was the foremans go to guy for frame lengthening/shortening jobs. This work drove him crazy because he knew what this work was doing to the strength of the frames, eventually he had to leave that job after the foreman asked him to shorten a truck for a customer because they didn't have the correct wheelbase truck in stock. On the final day of that job my friend noticed a bunch of new trucks come into the dealership, two days later the foreman came to him and asked him to lengthen one of the newly arrived trucks, you guessed it, the chunk of frame he had removed from the previous truck would fit perfectly in this new project. My friend stayed long enough to finish that job, but he quit when he was finished, he just couldn't do that work anymore. As I said it is you truck, my only suggestion is to shorten it to one of the factory wheelbases. I wish you continued good luck with your project.

There's no problem with shortening it, if the truck will suit your needs and end up as you want it. You need to figure out what you want as a finished product as none of us can answer that for you. Good luck!

Just spent the last half hour lookin' thru your album Benny,
that's one serious shop you got there. Good thing you got
40 acres to keep all them trucks on. What'cha gonna do with
them when you get them all restored???
Shorting the frame huh? Well I doubt that any judges would know
that you've done that if your plan is to show it, and as you
say, she's not gonna see any heavy duty luggin'n tootin' any
more. So a lot depends on what you have planned for her to
carry on her back. You probably have a flatbed or maybe a car
carrier in mind, no matter what, chances are you'll end up
fabricating it your self to fit the frame no matter what the
length.

Denny Graham
Sandwich, IL

I put the pictures of the ugly frame in my photobucket 46sparky, you tell me...lol...3B thank you! if I was going to cut the frame it would be to a factory length they made these trucks in 108in 136in 160in 178in 196in and I have all the dimensions to do it,( I wouldn't do it but my brother rick(1936only) would do the cutting and welding)....thanks 46gmcpu for your input...... Denny, Thank you, I don't know what I am going to do with them all but I sure am having fun working on them and buying them when they come around, I am not going to do the "show "thing, been there done that, I am just trying to save American Iron!

Shortening a frame by cutting and re-welding will not decrease the strength of the frame if the fabrication and welding is done correctly.

If fish plates and boxing plates are used it will actually make the frame stronger at the area of the modification.

Some fish plate examples:

http://i645.photobucket.com/albums/...0Truck%20Stuff/237150184_zpsf29200f5.jpg

http://i645.photobucket.com/albums/...t%20Truck%20Stuff/images_zps471e5763.jpg

http://i645.photobucket.com/albums/...uff/gallery_1277_6_97331_zpsb711cc29.jpg

http://i645.photobucket.com/albums/...0_0_100_100_gsframe64600_zps1192ba4b.jpg

Boxing plate layout (used this on my '27 Roadster Pickup):

http://i645.photobucket.com/albums/uu176/lakeroadster/1927%20Ford%20RPU/Untitled_zps1ef78597.jpg

http://i645.photobucket.com/albums/uu176/lakeroadster/1927%20Ford%20RPU/200305DSCF0030.jpg

Wow!!! That looks like someone was in a hurry to get it done.
My buddy cut the splint to cover the cut area from top to bottom and at least six inches to each side of the frame cut. After grinding, primer and paint it looked pretty good.

HR John, thanks for posting fish plate pic's. MY 48 3600 frame was shortened about 10" and I want to put it back...do you have any double fish plate examples? Also how did you get the welds on your '27 to look so good? Did you grind and bondo them? Holy Smoke !

A true fish plate is not supposed to have any horizontal or vertical sides and all "corners" should have a large radius.(a fish shape) If the splice is done on a angled place on the frame, then try not to have any sides that are parallel or perpendicular to frame angle. All this to prevent stress risers which induce cracks, Even though you don't plan on loading it, it is heavy. Also the recommendation for frame cutting/joining is a "Z" cut. It is not recommended to use thicker material than the frame and continuous welding all the way around is also not recommended. Boxing is for Hot Rods that have different suspensions, different loads. Not necessary IMO on our trucks. Possibly taking away a designed-in allowable twisting torque which will stress the frame. The newer trucks are solid rect. tubes, bent and seam welded/hydroformed (like a box). The modern truck is a totally different animal. "C" channel is still used also.
I can't imagine what must have happened to that truck, is it just one side? Two places? Do you think that they spliced in a piece from another truck?

Bart, describe the z cut a little more, in terms of a 4 " frame. I remember a Gearz episode where my man Stacey David converted a long bed to a short bed and used a kind of a z on it's side, but no fish plate, and he may have boxed the back side. Thoughts ?

The idea is not to have a straight cut. It is better to have a miter or a stepped cut. Both enable the top portion to rest on the bottom portion of the join. This of course means that the downward load is not on the weld. The "Z" is the miter cut, you can simply cut the whole frame, including the top and bottom flanges, at an angle. Most do 30 deg...or you can cut the flanges straight and the side of the channel at an angle..... Or you can do a stepped cut, cut down to middle, then horizontal, then down. In the stepped cut you must have no 90 deg corners, you will have to mate radii to radii. Large'ish type radii, depending on height of rail. I would make a good pattern that can be used on both sides. I would not measure a scribe separately. I also would not use a reciprocating saw.
There is a term "Z ing" the frame. This is a totally different thing used for body dropping/lowering.

Bartamos, I don't know what happened to this truck but if it could talk I am sure we would know, from the PO he said it was a water truck, its all the same frame, no patch, the rear repair is done ok and I might leave that alone but the front repair is really bad and you can see the wave in the frame, I thank you all for your input, it really helps! whatever I do I will get this old beast up and running again! but if there is one thing that can not be fixed, it could get hard since nobody has anything for these old trucks. Dan

The welds on the ’27 were done using flux core, by an ASME Section IX qualified welder. When it comes to structural welds I tack everything and then have a “real” welder do the welds. Since the guy is a pro the welds were very smooth. After welding the frame was sandblasted and then the body shop handled priming and body filler.

Benny check out this link. It helps to visually explain what Bartamous discussed. There are a lot of ways to skin this cat: http://67-72chevytrucks.com/vboard/showthread.php?t=123624

Nice work Hot Rod John, I've done some NHRA chassis' and rods in Southern Cal. Beautiful workmanship. I'll be doing Baldybenny's trucks this Spring, the Big stuff is easy.

WOW, nice hookup with THE man. Maybe you guys can come back and post a few pics of the cut and weld process?

Thanks Hot Rod John, Nice link! Bartamos, I plan to take pictures all the way though, My brother(1936only)is the welder, fab man, I am the engine man. I think we can do it all on this truck. time will tell and pictures you will see. Dan

Looking forward to the progress photo's and dialogue!