Thread: boxing a frame

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I had heard a lot about boxing old frames to re-use them. If I am right, it refers to welding a cover plate of equal thickness across the bottom of an U-bent frame, thus increasing strength and rigidity.

I was assuming my '36 chevrolet master sedan frame would need to be boxed. However, today I took a look and it appears to already have a cover plate across the frame bottom; factory installed.

?

i have a 36 standard town sedan it has a upside down u shaped frame with a plate rivited to the bottom. some 36 model came with a straight axle, some came with a independt front susp. they also had a frame with a c shape an a x member. 34 35 36 were mixed up with different changes on different models. i believe standard models were 109 inch wheel base an masters were112 inch that should be where you can tell the difference. a lot of parts look a like but wont interchange. jonathan

As far as I know, boxing began with the "C" shaped early Ford frames when goofy young hot rodders began installing modern overhead valve V8 motors. The plates were welded to the side of the frame sections to enclose them into a box section.

You threw me for a second when you said you weld a plate across the "bottom" of the frame rails..........every boxing job I have known about entailed welding a plate to the "inside" portion of the frame, where the was no wall originally. But I am familiar with Ford frames, and I guess from reading this that Chevy frames of that era were open on the underside. That's interesting, didn't know that.

Anyway, regardless of what section is open, the procedure should be essentially the same. You would cut some flat stock of approximately the same thickness as the existing frame (or something like 3/16 thick steel) and shape it so it either caps the open wall, or so it is slightly smaller so it slips inside it, then weld it solidly in place. Some people only weld it in with lots of short welds, and some fully weld it in place. The latter is how we have always done it.

The reason for doing it is strength and rigidity. These old car frames, especially ones from cars like Model A Fords, were notoriously flexible.........and that was by design. They wanted the car to twist to conform to the rutted roads of that time. But as Richard mentioned, once we crazy kids started shoving a lot more HP into the cars than they were ever meant to take, we had to find ways to make the frames stronger.

My Kid just got done boxing the frame we built for his RPU. He elected to have rails bent up to simulate the appearance of a Deuce frame somewhat, and then box the back wall for more strength and a nicer appearance. The picture below will show how we slid the boxing plate slightly inside the frame before welding, which allows stuff like brake lines and cables to be hidden slightly in the inset portion.

Don

Yes, the late '30's Chevy frames are already boxed from the factory. For those who have never looked at these, the frame channel is an upside-down U with a lip on both edges. Then a flat "boxing plate" is riveted and spot-welded across the bottom of the channel. Back before the advent of fabricated box-tube frames with independent front suspension, the east coast Modified guys really liked these old GM frames. They were lighter than the '40 - '48 Ford frame, had no X-member in the way, but are quite rigid. The hot setup was a '36 -'39 Chevy or Pontiac frame with '47 - '48 Ford front axle, spring, & split 'bones, big Olds, Pontiac, or 9" Ford rear on parallel leaf springs and the coupe body of your choice. Stuff in a healthy V-8 from your favorite manufacturer and go racing...

If your frame is in reasonably good shape, it should require no additional boxing.

here is a picture of a stock 36 frame.DSC00348.JPG jonathan

chevy use that type of frame up to 54 and they are very strong i have that type of frame under my car and i am putting some power thru it .i x brace it with dom when i put my ladder bar loop in

Way cool. The frame is stock with 'kick ups' for the rear axle, and is factory 'boxed' so it should do fine for the 301 I have for it.

My brother in law supplied an 'open' disc brake rear end from a ( 84?) firebird.

Looking at the rear end, it would appear as if its stock installation was a hot set up.

Thanks much for the replies.

Chevy called their style of frame the torque box frame.

Originally Posted by firebird77clone

Way cool. The frame is stock with 'kick ups' for the rear axle, and is factory 'boxed' so it should do fine for the 301 I have for it.

My brother in law supplied an 'open' disc brake rear end from a ( 84?) firebird.

Looking at the rear end, it would appear as if its stock installation was a hot set up.

Thanks much for the replies.

yes i had a 468 bbc roller engine with all stock frame stufff with a ford 9 did some small up grades with the 548 still using the stock rapped spring s has a front frame clip i did 20+ years ago . it works