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Hi folks,

Have a 54 3600. Im looking to box at least a few sections of the frame. Ive found precut plates for the 3100 online, my question is reference the frame. I know the frames are different in width and length but is each rail the same height? Ie- if i buy 3100 boxing plates, will they be the right size to weld onto the frame?

3100 frame channels are 5-3/4" deep while 3600 frame channels are 5-27/32" deep, so about 3/32" deeper. That's outside-to-outside dimensions.
Channel thicknesses are 9/64" for 3100, and 3/16" for 3600. So if the 3100 plates are a full 5-3/4" wide, you might get by with them.
Info is from the '51 Chevy Truck info from the GM Heritage center. Should be the same or close for '54.

GM Vehicle Information Kits

What is your purpose of boxing? Guys have been putting all kings of motors and mods in old trucks and cars before "boxing" was a thing. Never seen a broken frame except on a airborne ditch jump.
Truck frames were meant to flex. Boxing is for a hot rods without crossmembers and cut up frames with no suspension.

Im putting 4 link in the rear. Due to some issues with the company i bought it from and sending the wrong instructions, I now need to box a section of the rear in order to mount the 4 link inside the frame rails rather than outside. I'll be putting a mild 350 in it, so I'm not worried about the whole thing more than this one section.

This is incredibly helpful, thank you

When boxing a frame, for whatever the reason, it is a good idea to gently terminate the added pieces by tapering them to take the stress off a single location.

Ed

I've never seen a boxed frame that didn't develop stress cracks, eventually, and my friends on the dirt tracks from Tennessee to California have boxed dozens of them, mostly tri-5 Chevy units. We used to search far and wide for station wagon frames to build our cars with, the ones that ran a factory assembled square tube instead of a C channel frame. If you put an elliptical shape at both ends of the boxing plate, it will delay the inevitable for a little while.
Jerry

Jerry would you still find the same issue with 12" boxed on either side in the rear?

Im just deciding whether i should box the 12" to attach the 4-link or if i should get some more brackets and weld them on the rear axel (wider than the instructions they sent) in order to accommodate using the outer frame rail instead.

He is boxing not fish plating. Boxing will not, in itself, cause stress risers. Splicing a frame using fish plate is another issue. Not to be confused here.
So Montana, are you closing in the C channel open side to make a "BOX" or something else?
It is probably better not to run a long bead the whole way on the C channel legs.
POST PICS of the issue and area.

......"in order to accommodate using the outer frame rail instead."

What is meant by "outer frame rail" as opposed to "frame rail"? A "C" channel has one web and two legs.

Pictures added.

As it stands now I'll need to weld a plate on the inside to close the C into a box in order to attach the 4 link bracket.

Sorry my terminology, by outside id have to attach this bracket on the flat face, solid side of the current 'C'

It sure will if you don't box the entire frame member end to end. If you box a short section (close the open side of the C channel), there will be a stress riser where the closing plate terminates, especially if it terminates in a right angle to the frame. Jerry's comment about putting an eliptical end on the boxing plate reduces the stress where the plate ends by incorporating a little bit of flexibility there. And a 4-link mount on the boxing plate is going to introduce some twisting to the C channel, boxed or not. It WILL eventually crack.

If the open end of the box section does not end downhill for drainage, add a substantial hole at the lowest point to prevent water/ice/leaf buildup.

Kevin, if a person is boxing a section of a C channel, they are welding a plate to the 3/16 edge of the channel. Most of the plate is in midair. The elliptical shape/fish mouth is in midair. It will do nothing to alleviate a perceived stress riser.

Montana, I see you are holding a bracket in your hand. I assume this is what we are trying to mount in this post. I will assume you are holding it where you want it to be located. If so, make a rectangular plate from scrap steel, stitch weld it to the C channel and bolt the bracket to it. Or use a piece of rectangular tubing as a spacer and bolt it all together. or use a C channel the same size and bolt one leg on top of frame top leg and one leg on top of frame bottom leg. (two "C"s bolted together). You are not boxing a frame, you are trying to attach a bracket. Think outside the "box". Modify the bracket to be bolted maybe. Bolts are strong and permanent and this stress riser talk will end.

Can you give us the part number and company of the kit? Many of these kits are bolt on. May be your question should have been to ask how to mount that bracket. It should not have a been a boxing question. We may have some good ideas for mounting the bracket if we can see what was supposed to be done and what mistake was made. Glad to help.
My opinion: Try to avoid welding to a frame. I think you are thinking what I'm thinking. You are forming a plan. That's good a thing.

Does the rectangular plate have to come from scrap steel? Can't it come from new steel?

Thank you bartamos.

You were spot on i should've titled this "how do i mount this bracket" instead of what i did.

I bought the TCI 4-link rear suspension for up to 1954 3/4 ton Chevy trucks

https://totalcostinvolved.com/products/1947-1954-chevy-pickup-4-link-rear-suspension/

On that page is the PDF for installation, indicating the axle brackets need to be welded 33" apart with the frame brackets provided sitting inside the frame rail.

After welding up the axle, i came to mount the hardware to the frame and realized it wasn't the same as the instructions. I called TCI and they told me to follow the instructions for the 4 link for their Chevy 55-59 trucks as that is the frame bracket they had included in the kit.

https://totalcostinvolved.com/products/1955-1959-chevy-pickup-4-link-rear-suspension/.

As you'll see there the brackets should've been welded to the axle at 36" apart and the frame bracket provided shouldve sat outside the frame rail. Given the axle is done, my only choice now after calling TCI is to move these brackets inside (despite being designed for outside) and they recommended boxing that part of the frame so i had something to mount it to.

All in all im frustrated TCI messed up and im having to fix it, but thats life sometimes.

I don't have much experience which is why ive come here to bend the ear of you guys that do. Im open to any and all suggestions.

Let's hold off on any more welding or installation. Why in the world would a well known, advertised in all the magazines, chassis and suspension company not just tell you to send back the brackets and whatever else..... and send you the correct brackets? Their "fix" idea is WRONG, out of spec, made up, voids the warranty, totally their fault, involves "boxing", can cause unforeseen problems, risk for you, not what you ordered, involves heating up, and welding on, a frame which is not a good idea anytime. If something happens, you will be blamed.

Absolutely the wrong approach here, Am I missing something? A conversation with them you had? DO NOT EXCEPT THIS WORK AROUND.
Their "return policy" says claims must be made in 10 days. They can not expect that you would "catch their error" until you got to the frame bracket phase.

If I am not missing something. email them and tell them you reject there plan, no matter if you accepted it or not. You have been advised that this is not advisable. Do not communicate by phone. You need an email string of events and answers. Get to the boss.

I should have said "New Scrap Metal". In Marks area they would call them remnants. Hoity toity SoCal. Everybody knows old scrap metal ain't good for nothin. New metal is the way to go to avoid serious ramifications and corns on your feet.

I understand what boxing a C channel is. We're just going to have to disagree about how it will increase stress at the end of the boxed section, elliptical cutout or not.

I do agree that welding in a boxed section for a mounting bracket is not the correct approach for the OP. The vendor should fix their screw-up.

1 out of 2 ain't bad.

I added short boxing plates in front of my 10 bolt on my '50 3100. I've moved my shock mounts inside the frame rails. When prepping the frame for blasting, I removed the old rear upper shock mounts. I noticed that the frame was slightly concaved behind them. May have been due to rust although the frame didn't appear to have deteriorated...there was however "scaling" rust between the mounts and the frame. It was hard to tell which it came from. I suppose the shape of the frame in this location could possibly have come from stress...just guessing. I weighed the issue of the plates vs. a potential weakened frame in this area.

It looks like TCI does not know the frame for your 3/4 ton is not the same width as the 55-9 frame. If you weld the axle brackets at 36" apart, they will still be wrong. Their generic instructions for 47-54 should have specified for short bed only. You are in good position to provide TCI valuable R&D information, possibly including photos, and they should be able to provide the kit correctly at reduced or zero price.

Those of us in the repro parts business often rely on information from customers to get the parts right. Unfortunately we don't have access to drawings and specifications for every truck. They should treat you right.

Mark

I think they do know the difference. They sell two different kits. He has welded the axle brackets at the correct dimension for his truck. They sent the wrong frame brackets but the correct instructions. It's just a matter of getting the correct frame brackets instead of some kind if work around fix. That's what I see. I wish he would confirm if he agrees or doesn't. He may have done some other work that is undoable?

Actually he welded the brackets at the correct dimension for a 1/2 ton truck, not his 3/4 ton truck. Frames are totally different and that 33" spacing will not work for his 3/4 ton frame regardless of which brackets. It certainly would not work with the boxed frame workaround suggested. I hope the OP lets us know, it will be interesting to see how this plays out.

The GM engineers must have figured a rigid box frame can be connected to a flexible "C" channel frame without giving problems. Note on this factory S10 frame the splice (half way between tall cab mount brackets) has a long parabola (Nike "Swoosh") shape cut out to give a rigid to flexible transition area. I'm sure a boxing plate with the right shape is also trouble free. It's the square ends on plate that set up stress cracks. Also, DO NOT have the box plates of thicker material than the frame. If bolts need to be torqued to where they will cave in the boxing plate then weld through tubes from outer to inner surface to take the torque without collapsing.

[img]https://i.postimg.cc/JHRtmTyy/S10-028.jpg[/img]

Hmmm,
I guess metal is really precious. I'm wondering why they didn't run the boxed frame continuous instead of leaving a gap in the middle.
Bean counters, and maybe engineers trying to save an ounce or two in weight dictated that.
As far as "trouble free" I'm with HRL. More like "trouble delayed".

1. TCI sells a 4 bar for 1954 3/4 T. I will assume they tried to give him that kit. It is not the same kit as 1/2 T. 1/2T frame is 46" wide and 3/4 is 36" wide.
2. I don't know if that S10 graff is complete. Don't see a fish plate or anything but a partial box plate????
3. The TCI kits don't require boxing. Other types of modification kits do. Many times it's just for a plate to attach something to and give local "strength". It depends on the goal. In general, when "hot rodding" a truck if you want to increase load capacity, you box. If you want to strengthen twist, you add crossmembers. you can do both. Most of the Companies use "theoretical" Engineering. Many web articles are DIY engineers. (AKA Hot Rod Shops).
None of these kits have been tested in a lab, FEA, structural analysis, load calculations for every scenario and etc. The only builds that are structurally engineered are 8000 HP Top Fuel Dragsters, Funny Cars and Formula 1. Much of the design is driver safety related. Hot rodding a truck sometimes takes strengthening depending on Big HP, torque, weight transfer, etc. Dropping a 350 into a truck takes nothing.
4. For reference. Some old trucks have ladder frames, some X. Look at an aluminum ladder, it's frame is a C channel, the crossmembers are the rungs. You can use it as a foot bridge across a ditch. Take out several rungs and it will twist...... (I know, some are I beam frame, some are rectangular tube).

Could you post a link to the 54 3/4 ton instructions?

Don't have that. There is absolutely no mention of THIS kit on the TCI website. I'm not going to spend anymore time on this until poster has questions or info.

Someone wrote on the Speedway page, one year ago.
RE: TCI 4 link kit:
"the parts look nice. but I have the 3/4 ton truck some of the parts that were sent are for a 1/2 ton truck. some one is sending me the correct parts. but I will need to pay the body shop to repaint the new parts AGAIN".

TCI is all screwed up. Remind me to NEVER buy from them. They only say "Chevy Pickup" or "Chevy Truck". Nothing about 1/2T vs 3/4T kits or part numbers. Nothing on the website to help. As you say 33" CL to CL on the axle brackets won't work on a 3/4T 36" wide frame. The PO silence is scaring me. I found two different TCI part numbers for the 3/4T kit, (Speedway and EBAY) neither is found on their website search function.

If the S10 frame shown is not complete then GM left something off of everyone ever built because it's bone stock factory. As far as durability I haven't seen any broken in half S10's ANYWHERE even though they were designed by the real morons GM hires for engineers.

If my memory from 40+ years ago serves me correctly, the box-section station wagon frames we used for dirt track cars were made of two C-sections, one slightly smaller that the other so they could nest together, and they were skip-welded together on the top and bottom. Of course, we always chopped about a foot out of the center, fish-plated the joint back together, fabricated a roll cage that looked like a bridge builder's nightmare, and still developed stress cracks. Of course, blasting down a dirt straightaway that resembles the craters of the moon after a few laps and then bouncing around a slightly banked turn four times a lap might have had something to do with that! Evan can attest to how difficult it is to keep a circle track car in basically one piece!
Jerry

I have not looked at an S10 chassis before. It seems all wrong to splice a frame from the factory. It seems weak with a vertical weld splice. I see it has a boxed section in front that transitions to C. It seems like the swoosh and box section should be on the other side of the splice (run past the vert weld). Weird. I have not seen this splice in person but it is counter to everything I think, have seen and read about splicing a frame for shortening, lengthening, etc.
I asked because I missed that you said "factory splice", was looking for a fish plate on the outside and thought it was an unfinished splice job. As you say, it works.

Zooming up on Evan's pic, it looks like that front section is actually 2 C channels welded together on the flanges to form the box. The inner channel with the swoosh appears to overlap the vertical weld on the web by a bit and serves to reinforce that. They probably did that to make it a bit easier to form the pieces, longer ones being more difficult to form with the arches in the frame overall. Probably makes sense, and they likely did some stress analysis on it and decided it was OK for the application.

What is the reality of stress cracks next to boxing plates if your truck is only driven on pavement with no load in the box and no excessive torque issues from driving habits? Is it REALLY flexing to the degree of cracking? Just asking.

Smooth roads, no load, stock engine, near stock tires, conservative driving, I'd guess somewhere between eight hundred thousand and one million miles (TIC). There's a chance something else might wear out first.

How long will a stick-built house stand there if a tornado doesn't come along and destroy it or the termites don't get hungry? There are a few in Europe that are several centuries old!
Jerry

NO zooming!

bartamos, don’t know how or your system just won’t do it?

He's is cheating. No zooming allowed

NANNER NANNER!!
It's easy. Just hit CTL +
Oh Crap! I just let the secret out.

coilover..my point exactly. I'm coming up on 67 trips around the sun and I don't have my truck done yet. Much bigger issues in life, (and truck), to be concerned about! I'm positive that the number of annual miles driven, including those with possible excess acceleration, will decrease with my age. This is an observable statistic in our society...factory vehicles or stovebolts not withstanding.

Sorry for the delay in updates. I've been in touch with TCI in reference to the issue at hand.

For whatever reason when I ordered the 3/4 ton 4 link rear suspension it had included instructions for what I'm guessing is the half ton. The frame brackets were different (which I didn't realize until after the axle brackets had been welded on).

I've had a back and forth with TCI and they advised the following.

"Unfortunately due to the design of the brackets we have to send the axle brackets for you to re weld on the rear end"

When asked if the frame brackets included in the instructions that came with the kit were available for me to exchange the response was as follows,

"They exist but they are designed to work with the 55-59 chassis applications"

So I am left with two options,

1. Weld on the new axle brackets at the width specified with the 55-59 instructions.

Or

2. Plate the inside of the frame in order to make the frame mounts work inside the frame rather than outside (as shown in the 55-59 instructions)


At this point I'm leaning towards cutting off the axle brackets and welding on the new ones in the new, wider, location.

It's honestly been a fairly frustrating ordeal as the rear axle was custom built and I had sent them the brackets and original instructions in order to have these brackets affixed before it was finish painted.

I've been less than impressed with the communication with TCI and any sense of acceptance that they had screwed up in their instructions/kit. At this point i'm still not sure they really grasp what or where things went wrong.