Frame Boxing Tips and Advice....

Not that it matters, but I'm working on a 46' International Harvester K3 truck. Very long frame as it is the 1 Ton model with a long bed. I am about to box the very back of the frame and install new springs hangers and shackle mounts. Then I will get ready to put in motor and transmission mounts. I will use the universal crossmember style to help strengthen up the front of the frame. I'm keeping the straight axle front end so I'm not boxing the front.
My question is about making the frame level and square before boxing it.
looking for tips and advice.
Original crossmembers are still in place other than the transmission crossmember. Do I just make sure the frame rails are level across from each other as in a level sitting on each rail? Front and back?

 

If you don't have a HD steel table to mount the frame on I would weld 1 1/2 angle iron across the frame in several area's so the rails won't twist as much. I X brace mine to do any boxing. It's best to have a jig but not practical for one or two frames. Happy welding!

 

I level mine up with a long carpenters level front to back and side to side, or at least I use the longest level I can. Sometimes a long level won't work logistically.

As has been mentioned if you can't tie it down to a platen or frame table tack some cross (x) braces in after leveling.

The K3 should have a hell for stout frame from the factory. Are you sure that boxing is necessary? maybe just an X brace will do the trick for you.

 

Not telling you what to do, because I'm not familiar with YOUR truck...but I'd have to sit down for a bit and figure this thru.
I'm not sure if boxing the back half of your frame is a good idea.

You've got a long frame with solid axles/leaf springs front and rear. About a 1/3 of your suspension articulation is actually frame flex.
Stiffen up one end by boxing the back and your gonna focus the flex into the area where the boxing ends and the open channel begins. Thats gonna be near where the cab meets the box so you have no body stiffness helping in that area either.
I'm weary of cracks eventually forming in your frame.

I think I'd leave it open and flexy over its full length or box it from one end to the other. Most likely just save all the work and leave it open actually!
Hey, It's a Binder so I doubt the frame is weak or anything.

 

If the frames flex and twist, wouldn't the factory crossmembers that are riveted to the frame be loose by now? It has a stout X member about 3" in from the front of the frame and about 5" in on the back. Plus a couple others in the middle of the frame.
I was just boxing the back to creat a mounting surface for a custom rear bumper to mount to. If it's best to leave it, I will just box in the back of each frame rail on their own for a mounting surface for a bumper. With the factory rear crossmember right there at the end of the frame, I can't see how boxing it anymore there would make a difference. but I am a rookie ; )

 

You can check the rivets, but for the most part, the crossmembers flex to move with the frame. For most driving situations, you will hardly move the frame. If you want to see flex, take it off road and lift one wheel. Or jack up on side of the rear axle up as high as you can to see the frame flex. Don't lift one side of the front axle, I did this and luckily I am skinny, I can tuck in my stomach, and my tires are 32 inches tall. The jack stand slid along the axle, and fell off the curve near the spindle and dropped my truck.

 

You have a designer's intuition, if I understand your intention.
The open "C" shape will flex, but the original form of front and rear suspension work with it.
Henry, or in this case Mr. IH, got it right. Only when you need a great deal of additional stiffness, due to new loading values. or performance ch***is tuning needs, would it be worth to trouble to pursue boxing.

 

Jigging in place and then welding won't keep it from warping. The tension induced will move it anyhow after the Jig is removed.
Wait until after you are done with the mods. Then measure cross-corner and check for twist etc. with a level, etc. Chain and jack to bring it back if necessary.

 

I'm not gonna box it. Although I am gonna close up the "C" channel frame rails on the ends. The front, I'm welding in 1" id DOM Tube to use as the front shackle hangers. This way I can use poly bushings in the hangers. That size is what's used on CJs so they are easy to find and cheap. I'm also going to have my front springs fixed. I'm gonna have new main leafs made with the same 1" eyes so they use the same poly bushings. I might have them reverse the eyes as well.

 

I'm still gonna have to weld in crossmembers for the motor mounts, transmission mounts, and rear shocks. If the stock crossmembers in the truck were rivited to be able to flex, what happens when I weld in the 3 new crossmembers???

 

In a ladder type frame, you have front, rear and center members. The center one can be in a K or X form which would reduce the twist when compared to open "C" w/straight ladder members. Depending upon choices in the type of build, you can have "secondary" dropped tubes (ex: a stretched U) that support the trans or motor and bolt to the frame or upper X member in the case of the trans.

 

It wont flex as much. why do you need a crossmember for shocks? just weld tabs on the C channel to mount the shocks

 

I was just kinda using this as a guide. Although I'm using spring/shackle hangers that will just weld to the bottom of the frame. Figured this was the right way to do it.
http://www.cl***ictrucks.com/tech/0806clt_ford_f_1_rearend_pulling_up_the_rear/index.html

 

Not exactly the same frame design, but my '57 IH has a crack in the frame where rivets for the spring hanger and front cab mount go through. The factory manual has a procedure for repairing cracks, so they must have happened more than once - people tended to overload trucks and work them way harder than the designers thought likely. Just saying check for cracks near/through rivet holes. If there is one, weld it and weld a reinforcing plate on the inside (as per factory manual).
Chris

 

I've been stripping the frame down to bare metal and treating it with Ospho. I've yet to see any cracks. There is some serious pitting on the inside frame rail where the gas tank and battery box sits. The animals packed the area with leaves and twigs and must have been rottong for the last 20+ years. It's still solid but there are deep pitting in that area.

 

For wiring ease, tack weld some emt conduit inside frame rails before "Boxing". (both sides)--------Don

 

I'm no expert but I own 3 IHC's and they are heavy frames. I wouldn't bother boxing unless I was putting a hella big mill in it. Bill ^ is actually right about boxing the rear and focusing the flex on the front unboxed frame. I've seen it on a buddies A and the frame started cracking and sagging at the firewall. Leave it open and save the weight.

 

I'm not boxing it. Just closing the ends of the frame rails where I'm welding up custom spring hangers.The front will also have a theaded bumper mount on the end of the frame. I will use crossmember style motor and transmission mounts. Should I have them bolted to the frame or is welding them ok? All this talk about the frame flexing... Will the new crossmembers welded in cause problems too?

 

Thanks for the tip. Other than the very ends of the frame, I'm gonna leave the "C Channel" frame open.

 

OK, so things have changed and I want to revisit this again. Rather than stay with the straight axle, I'm going to the Jag IFS. I also won't be using the crossmember style motor mount, not enough room with the Jag crossmember right there. I might have to trim up the front crossmember on the frame to clear room for the swaybar to run under the nose of the frame. Maybe. If I do, now I lose strength in that crossmember. I may use the Jag IRS as well but an leaning at the 8.8 I have as it has the gearing I want. It will just be parallel leaf suspension in back.
So, with the IFS in front and parallel in back, should I box the frame? Also, the Jag IFS is gonna be factory rubber mounted, not welded in.

 

So here's where I'm at. I'm rubber mounting the IFS and IRS from a Jaguar.
Should I box in the entire C channel frame rails or just in the Engine area and rear suspension area leaving the portion under the cab open? Should I use the same gauge steel as my frame or can it be a bit thinner? Does it need to be welded all the way out or can it be welded every so many inches or ???

 

Here's my opinion...If the frame was 3/16" -- 12ga boxing is fine, 16ga for looks not strength...s***ch 1" skip 2", also precut some access holes for plumbing/wiring