Help! How should I box/strap my 75' frame?

[CJ5inFourWheelDrive]

Well all I got way into it, I striped my rig down to the frame and made a completely new front end that will get welded on in front of the radiator made out of entirely 1/4in. steel....it's very nice. Anyway while I got it down I figgure I'll just box and strap it, now I got a few questions. Because I got myself so far into this I no longer have the option of building a new frame WHICH IS ALOT EASIER TO DO THEN BOX AND FIX CRACKS....OK ALL YOU OLDER JEEP OWNERS.....DON'T BOTHER WITH THE FRAME BUILD A NEW ONE IT WILL BE 20X EASIER!!!!! Now that thats said, I cut the inner box back until the last frame plug weld and cut and removed that, now I need to know if the stitch welds on the box where the engine is all that holds it or is there plug welds? It's got some surface rust inside so I figgure before I box it I'll sandblast and paint the inside so it gets some protection. Now next question, I'm going to box it with all 1/4 in steel, but do I stitch weld it completely seamed or should I just stitch weld it every 2 inches for about an inch and call it good or what? Also what about strapping? The rear cross has been replaced and shaped with 5/8 as to create a smooth ass (looks nice), I'll also cut the 2 off in front of that and replace the stamped one with 2in. .250 wall tubing. And let that be the last one before the rear cross for whenever I design a big ass tank (down the road). I was going to seam the new 1/4in. on the inside and grind down the welds to make it all pretty but I'm wondering if I should do that or not. Same as on the strapping, is stich better then a full seam or what? I wish I wouldn't be so freggin touchy with doing things right , need your thoughts I want to get this done ASAP. BTW I've done some searching and people are saying to use 1.25 x 1/4in for strapping.
- Zach

[CSP]

That's either too many questions in one post or one question asked more than once. It hurts my head to try and separate them all.

I did see 1/4" thick for the boxing part. Why so damn thick??? Look at what the rest of the frame is. Going so thick will do nothing but add weight. Stay consistent with the thickness of the stock frame rail. 1/4" also seems way overkill for strapping. I like 3/16".

[1MrWillys]

Originally Posted by CSP

That's either too many questions in one post or one question asked more than once. It hurts my head to try and separate them all.

I did see 1/4" thick for the boxing part. Why so damn thick??? Look at what the rest of the frame is. Going so thick will do nothing but add weight. Stay consistent with the thickness of the stock frame rail. 1/4" also seems way overkill for strapping. I like 3/16".

What this guy said... Ditto. Plus, you must remember that 75 was designed to flex. So if you box the frame 100%. You better plan on a softer spring, or you'll lose alot of articulation. Maybe Wrangler leafs spring over... or link suspension?
Good Luck

[CJ5inFourWheelDrive]

FAWK THIS!!! I'M EXTREAMLY PISSED OFF I WASTED MY TIME SETTING UP THE REAR SUSPENSION AND SCULPTING THE REAR CROSSMEMBER!!! I cut the tack welds off the front end I made (probably about 60 hours into designing, building, preping and gathering materials to make it, not to mention over $100 bucks in steel and my time) and slid it off. So I'm sitting there thinking, my Jeep will be almost completely rebuilt at the end of this 2'nd frame off resto so WTF! Why should I be running 1 ton running gear on an almost 30yr. old frame thats a piece of shit! Especially when I'll be running an almost 400hp AMC 360 at the end of next summer. So I said screw it, esp when I picked up the front rail and the thing will twist around pretty easily, it's not worth it! I just paypaled for a set of 75' CJ5 frame specs. I'll go in debt and have it done right this time by building a frame, I know I would have been done long ago had I just chose to do that from the beginning. PLEASE PLEASE PLEASE let this thread be a lesson to those of you running early style frames and are contemplating boxing and other intensive work. It simply isn't worth your time because in the end your just polishing a turd. Yes it will cost more to build a frame, but it's less time intensive then wasting your time on something that will only last a few years at best. I'm using 2x4 rectanglar tubing in the 1/4in. variety so it lasts.
- Zach

[GPERX4]

Good choise mine is 1/4 inch box with 1/4 inch strap on the botttom. I like the stiff frame because the clutch doesn't bind anymore. YJ springs and ssr handles great.

[Kaiser5]

CJ5 is right. Spend the cash on a good frame up front. When I tore my '69 CJ5 down to build my Scrambler the frame was trashed. 15 years of abuse and multiple trail fixes, add-ons and fatigue had beat that frame up bad. Right before I cut it up you could pick up the front corner of the frame a foot off the ground and the rear crossmember would still be flat on the ground!

[Jaffer]

I've been saving this good photo example of how to strap a frame ...
... and seem to remember it was the concensus that stitching them was prefered ...

[fubar73cj5]

Amen. Made the mistake of building on an old frame, will work long enough to build the new frame. Also gave me a lot of ideas on what I want to do different next time, but wasted a lot of time and $ on something that will end up trash. Be patient like everyone says, it'll be worth it.

[Geesh]

Originally Posted by CJ5inFourWheelDrive

FAWK THIS!!! I'M EXTREAMLY PISSED OFF I WASTED MY TIME . . . so WTF! Why should I be running 1 ton running gear on an almost 30yr. old frame thats a piece of shit!. . . Yes it will cost more to build a frame, but it's less time intensive then wasting your time on something that will only last a few years at best. I'm using 2x4 rectanglar tubing in the 1/4in. variety so it lasts.
- Zach

thank God I have this board. On mine, that's just what I did: made a frame from the ground up. Turns out it was easier than setting up the gears and locker in one axle. Some thoughts after doing it myself:

• I would suggest not going after the original CJ-5 design; way too complex and uneeded for our sport. You want a longer wheelbase anyway, so go with a simple, rectangular frame design.
• Wall thickness doesn't buy you strength, it only adds weight The right material properties and section properties do the trick if you want a stout frame design. Think 0.125" wall, A36 (or A500) domestic steel, 4x2.5" rectangular tube. This aids in mounting to 2.5" wide leaf springs and increases section properties
• Also be strategic in crossbracing the frame; it'll make it stronger in torsion (a frame's nemesis)
• keep it simple, stupid. There are several excellent threads here that cover simple, strong frame design

I've walked in your shoes and it sucked ass realizing a ground-up frame build is needed. But it is soo the right thing to do. Mounting all that trick, technical, high-performance hardware on a vintage noodle is shortsighted and frankly ignorant.

Good job on sucking it up and doing it right, as well as letting us learn from your experience -

here's the beginnings of my frame build, simple and light; I hope it helps. I have the design on CAD if you want it, though it's for a older CJ-5 (short front clip); it's nearly done now

Good luck, keep us posted

[CJ5inFourWheelDrive]

Geesh, do you have anything mounted to your frame yet? I could wip something like that out in a weekend afternoon, looks like a good design but I'm harping on making it complex to semi-follow the lines of a CJ frame. BTW I've already made a C channel and plate front piece out of 1/4in. ....I need to get a pic....need a cam I guess. Which I would like to integrate into the new frame...simply because it's there and I put the design and build time in it. Anyway it's got D ring mounts integrated with it along with the SRS brackets and it's designed very nice and with bracing on the backside of the mounts so I want to work that in there. So far I'm thinking something like ---\____/--\- if that makes any sense. The frame will stand to be lengthened 6 inches in the front and probably 2 in the rear. I got 3 extra inches of W.B. in the rear of the old frame by using stock 76-86 rear CJ hangers and utilizing old hanger holes. BTW my garage looks like yours now but I have an engine on my stand .

[CJ5inFourWheelDrive]

Geesh, do you know if theres differences in 2x4x1/4 box and all others....I guess is there different types of box like DOM or what not?

[Brian1]

Cj5in4wd, Geesh does have his body, engine, axles etc mounted to his frame. the pic he had was probably when he built it. Im sure he will post up some more pics of it.

The picture Jaffer posted is actually of my frame. It is a 42 GPW frame and came partially boxed from the factory. I strapped the top and bottom of it with 2" x 1/4" and I also plated the insides with 1/4". The straps are stitch welded. As others have said, if I were to do it again I would make my own as it would be less work.

[Geesh]

Hey Hey -

When I spec tubing for jobs, I usually call for A-500. I don't know if this helps, but Grade A (the weakest) A-500 tubing has a tensile of 45ksi and a yield of 39ksi. For reference, typical 1010 DOM is 70ksi tensile and 60ksi yield. Regardless, the value for the a-500 is pretty good. Grade C A-500 comes close to DOM round. But expect to drop bank for that madness.

The other reason I spec domestic grade is straightness, flatness, perpendicularity. This plays a more critical role when you do a long straight frame like mine. If you're mandrel bending metal, it may save you bank (with some risk in strength) to go foreign.

I have yet to run across tubing of that size that isn't seamed; I would surmise most structural tubing (everything not round, hex, oval) is seamed.

I caution you to re-think wall thickness for your tubing. Go 3/16" wall at least. You don't get all that much by adding thickness; tis better to increase the tubing size. Heck, go 4.5x3x0.312 if you want a stout frame.

I will be shortly doing the final tear-down and weld-up prior to getting it running. I will take pics and post em if interested. If possible, keep us apprasied of what you're doing. Should my 'morfidite' not work (or prove too embarrassing), I will consider something more complex -

Good luck

[edit] FWIW: I learned how to weld when i was making my frame. The above photo shows the frame about a foot longer on each end than it will be when done. I left this extra part on front and rear for two reasons

• to provide straightness and have something to rest on stands while building the rest of the rig
• since the end braces were my first serious welds, they will get cut-off when done, allowing me to scrap the boogers

[CJ5inFourWheelDrive]

Woo thanks for the info Geesh, so what grade did you use? Do they produce 1010 in 2x4x3/16? Looks like I'll be using 3/16 because from what everyone says I won't gain any strength by going to 1/4, just weight. If you don't mind me asking, what did your tubing run ya a foot? And what does grade C usually run? I guess i'm looking for the strenght of 1/4 and the weight of 3/16, if thats possible? What should I tell my steel provider to order in (Brand wise). And do you think this material will be a viable option for a frame being welded together to follow stock CJ lines. Sorry for the 21 questions deal, thanks man and for ya, definetly some good ass info and I highly appreciate it.

[Geesh]

No worries on the info; my pleasure ;D My frame tubes are 4x2.5", 0.120 wall, A-500A. I had to have 'em shipped from Denver, as the 4x2.5 shape is rare here in the boondocks. Cost me $400 for four sticks ($5/ft). I still have a lot leftover. The benefit of the wider tube is the added strength due to the increased section properties.

In PA, you are in paradise for steel; perhaps you can get to know someone who can hook you up. Expect to pay roughly double for the good stuff (grade B or better). I'm not sure how you're welding the frame together, so I can't comment besides the basic advice of stress-relieving as you go. But if you're running small lengths between welds, you may not get a whole lot of benefit from the more expensive metal, as you weaken the material sufficiently to make the extra benefit inconsequential.

Note that I am strapping the bottom of my frame in between the front and rear spring mounts with 2.5" wide 5/16" strap (old emergency ladder from a building ~ free!). Each length is a bit more than 3' but will serve as a threaded nut plate whgile providing some good skid protection.

Lastly, I believe trussing the frame as much as possible adds a whole lot of torsional stiffness without a whole lot of weight, if done correctly. That's how I plan on getting away with 0.120 wall.

[CJ5inFourWheelDrive]

NICE, thanks Geesh, any special welding techniques, I like my C's but if it requires stacked dime style or straight push or whatnot then I can do that too.
- Zach

[Geesh]

no special welding techniques ~ I am not that seasoned yet. I just try to make sure the bead sits in the joint well and not on top. Alot of heat and alot of feed. I also now appreciate the value of prep work, proper jigging, and making damn certain the polarity on the welder is not set for flux wire when shielding gas is used. . . . .D'oh

[CJ5inFourWheelDrive]

Haha, yea the polarity will get ya, how did you jig it up?

[Shades76cj5]

Geesh, nice frame. And thanks for all the info you guys are providing in this thread. Much appreciated. Makes me want to tear mine apart.

[CJ5inFourWheelDrive]

Go for it Shades....:-D then I won't be alone in not having a running rig ;-) hehehehe. TTT for Geesh

[CJ5inFourWheelDrive]

Geesh you have PM's
- Zach

[dhoffroad]

geesh, nice job I knew someone else had to have done this style too. I poasted a pic of mine on the homebrew tube frame pic