Total newb to this process, but I have a 26' long truck that I'm considering lopping off 4' off the back of the flatbed. It's a standard C channel frame, although I couldn't tell you what gauge the frame is off the top of my head. It's probably an 8" wide frame iirc, maybe 6". What sort of cutting tool would I need to use to trim up the frame? Is there a tool that would cut as well as use a different disc for sanding on the body later for paint? Is there a rule or guide to take in how close to the rear spring perch when doing this? This is a 2T truck and I figured if I left a foot of frame past the back spring perch and put in a cross brace there, that should be safe and smart. Someone suggested doing a dovetail instead of a cut job, depending on my help, I might take this on. The goal though would be for a standard load carrying tail drop and not anything needing to support a full vehicle. I picture I would insert a box beam across the back and then drop the lower angled portion from that, if I did decide to go the dovetail route. Thanks in advance for your comments and suggestions.
Depends on what tools you already have. Sawzall, or diegrinder would be my choice. I have used a hacksaw to cut up a frame in my younger days. That would work, it's just mild steel, and all it takes is time. In the little books, they always used a torch.
I'll offer a couple of random thoughts.... I'll suggest chopping up some photos to get a feel for the final proportions. Having the rear wheels too close to the rear will likely look a bit goofy. Having the rear axle too far aft will also throw off the weight carrying capacity as more of what ever you are carrying will shift to the front. Now, all depending on the vintage of the frame, older truck frames were made of 'bigger stuff' rather than better alloy stuff, you may want to consider removing your 4' section from the area ahead of the axle. The piece that is removed then is used to box the splice. This can work very well but needs to be done properly and then, again, much depends on the vintage. .
I've cut and spliced a few truck frames. I use a worm drive Skilsaw and a metal cutting blade. Most of the light, cheepo, sidewinder saws don't have enough grunt to cut a frame in half, but with patience I suppose one will work
I am not sure, but when I took 21 inches out of a long bed pickup, I had to take it out of the middle, between the rear of the cab and in front of the rear axle. Like 73RR said, I did use the sections taken out as boxing material for the area where the cut was made. also, I didn't just cut the frame in a straight line, but made a modified "Z" cut. this was made on a non-H.A.M.B. type vehicle.
Whatever you cut it with, be sure you cut it diagonally. Vertical cuts in truck frames have cracked right alongside the welds. (even when 'gloved' inside; a 'vibration frequency' induction) Also, many truck frames were 'hardened', and may not be likable candidates for saw blades.
Interesting thought. It's likely way over my capabilities, but maybe not. This puppy has 3 driveshafts and a 195" wb, so there's definitely room to work with there. It's a Studebaker 2R17 fwiw. So, if I follow your idea, you would cut out X amount of frame in the middle, flip the cut piece 180 degrees and weld it back into the frame? Fishplate the outside of the frame then, as well on the outside of the cut?
I'm not sure which diagonal you're referring to, vertically from top to bottom of the frame, or along the width of the metal gauge? Sorry if that is too obvious a question to answer, I can picture either direction you describe from your description.
Ok, after reading Coconuts' post, now I understand what you two are referencing. I remember watching a video for a long bed Chevy truck to short bed conversion kit that is out there and I saw how he made a Z cut in the frame when he did that. Would you then flip and place the removed frame piece on top of the frame or up under the cut frame section? Does it matter? What suggestions can anyone offer if this is done with an oxy/acetylene rig?
I'm pretty sure I have access to a Sawzall, but I am curious as to the difference in doing this with a Sawzall vs. a grinder with a cutting blade. I don't know, but I assume with a grinder you have the option of using sanding discs, if I were to try to clean the cab off to paint, at some point down the road.
If you're looking to bob the tail that's one thing- jist hack it off. A novice can find himself in trouble using a cut off wheel. I'd say use a saw-all. If you want to reduce the wheel base, look at moving the spring hangers forward and then just bob the tail. If you can do that there's no welding or joinery.
Sounds like your main concern so far is what tool to use. I would use an angle grinder with a cut off wheel. Scribe your lines, and cut it with some meat left then switch to a grinding wheel and final grind to your line. Can you post a side pic of the truck and or frame.
You're probably going to have to buy more than one power tool, by the time you're done with this project! I'd probably use a torch to cut off the back of the frame. But I'm a hack.
Well, that would still entail removing one of the 3 driveshafts on this unit. It's 195" wb and a 2 speed rear axle with dual wheels.
I have pics on a thread I started here: http://www.jalopyjournal.com/forum/threads/in-for-a-penny-in-for-2-tons.991978/
LOL, I'm fortunate to be parked at someone's mega garage (he has a 4 point lift inside), and he has some equipment, so I'm likely wanting to use what I have access to, but since I treading water in the deep end here, I thought I'd ask for suggestions on the different options I know I could go.
Could you explain, in gory detail if you'd like, what sort of trouble a wheel leads to vs. a sawzall? Frankly, I've used a sawzall on something smaller not too long ago and my thought is the sawzall is more unwieldy and unstable than a grinding wheel seems it would be but then all I've done is stay at a Holiday Inn Express last night fwiw.
Torch or maybe plasma if you have it. Z'ed if in the middle, straight whack on the back. I do like the moving the spring hanger idea better if shortening the WB. Driveshafts are no big thing, most sizable towns have a driveline shop. Good Luck.
thats as commercial truck frame ( straight truck ) , the rails are more than likely hardened , for a ct frame we use a k-12 or gas powered saw with a steel grit blade ( yan rent them ) and you have to cut the tails diagnol/dovetail on the end and put a spacer within a foot of the ends ( parallel to the frame members as it will keep the frame from spreading ) and the spacer must be bolted not welded ( the holes should be drilled and peened )to the frame rails , Do not torch it as it will make the metal brittle and it will crack at the bends or around the holes , we try to keep 6" of steel past the rear hanger , if you do a mid frame you some times find holes predrilled for the spring hangers , if not move the hangers forward , do not cut , splice and fishplate the frame as it might be a crack starter as the metal is old and work /age hardened .
Okay, if you want to shorten the wheelbase, I would move the rear end forward and cut it out with a torch. If you was going to cut it strait he up and weld it back together I would use a thin cut off wheel, on a big anglegrinder. The put it on something, and do the rest with a small anglegrinder. And the make a deep wedge in from both sides, if you want to weld it back up again. I would dowetail it, so you got more options for the use of it! A truck that can earn it's keep, you don't have to convince your wife why you need too keep. I would make long ramps, and make it so they can double as bed sides when you need to move something else! So you got the option to use it for cars, tires, building surplies, Carnevale, local fair/parade, taking out the junk/garbage, moving gravel or stones. Maybe install a small winch.
Oh yea, one other thing, some old guy show me. Drill two holes, so that one hole is on one side of the cut and the other is on other side. Do this on both the right and left frame rails. Make them level to the floor and (very important) make them equal distance apart. For example, the right side holes are level to each other and 24 inches apart, make the left side the same way. After your cut the frame and you are sliding it back together, make sure the holes are the same distance apart. If you cut out 21 inches of the frame both the right and left frame rails holes should be 3 inches apart and level with the floor. One more item brace the frame at both sides of the cut, and make it level with the floor and have a way to slide the frame back together.
I'm curious now to check out the truck and see if there are alternate mounting holes for the spring perches.
Where I worked, we simply moved the spring shackle mounts up the frame rail to get our desired wheelbase....drill new holes to mount them and slice off the back of the frame rails with a torch. We had a really nice drill on wheels that chained to the frame rail and the drill operator just turned a wheel to push the drill into the metal. Had a huge chuck for big drill bits. You could drill graduated size holes by hand until you achieved the hole size you needed... Better than cutting and welding IMHO.
I'd agree with Rocky on moving the axle and associated hardware rather than cutting a section out of the middle of the frame. We've shortened them and lengthened them in our shop in the past, and making the joints in the middle of a frame isn't a job for an amateur. If the rails are mild steel, then you need to weld with 7018. If they're alloy steel, then the normal practice is to use 11018 rod. Most of the welding is out of position, and its easy to run a bunch of slag into the welds due to the heavy flux on low hydrogen rods. Given the age of a Studebaker, my guess is that the rails are mild steel. You can rent a mag base drill at most tool rental places, and it makes the job of drilling holes for the spring hangers, etc pretty simple. Its sorta difficult to push a big hand held drill thru the side of a frame rail since you end up pushing yourself backward rather than pushing the drill forward.
Yeah if the frame is straight on one, that will allow this, just grind off the rivit heads on the hangers to frame ,knock em out and scoot the whole works forward to specs or desired location as long as its the exact same distance back on both sides I put grade 8 bolts in mine...??? and just used a standard drill, I did buy a new bit for the job tho, having the good drill bit and keeping it lubed and cool made all the difference. Ive done it both ways and scooting it forward on the frame is a lot easier.
Message heard. It's part of the decision making process when you don't know what you're doing. An opportunity arises and you have to weigh what you want to tackle or have the tools to tackle. Right now, things are not set in one direction, so it's evaluatin' time. All the comments have been great and very informed. Thank you to everyone who's shared your experiences.
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