Building frame from scratch? Input desired

Tony Raine · Feb 9, 2011

Its cold outside, and my B2 is outside. Time to daydream.... Inside, where its warm.

I know my stock frame is not going to last forever. I also know that it looks like 2 wet noodles were used as a model for its creation.

So I have decided to design a replacement frame. Something simple, that an average joe could set up, and have a qualified welder assemble. I want stock/off the shelf parts to bolt to it as well. No point designing everything when there are plenty of decent parts out there at competitive prices. I have steel available locally in 20' sticks, so material is a short drive and a shrinking wallet away.

I'm thinking 2" x 4" box steel for the main rails. What thickness should I use? I'm not a "hard-core" wheeler, so I want the lightest weight. Isn't a stock frame somewhere around 1/8" thick? Oh yeah, no tube. Benders are expensive, and its easier to bolt stuff onto a flat surface.

Stock(ish) parts i want to re-use:
-body mounts (unless i happen to have a bunch of extra mat'l left)
-my Duff coil mounts
-F250 shock mounts
-leaf spring perches
-an "outside frame mount" steering box from something.
-my Duff rear bumper/tire carrier combo

Currently I am drawing up a rough sketch, that I will post up when I get more done. When I get it where I want it, I will start applying dimensions. After that I will make a final sketch to scale.

86 slo-vo · Feb 10, 2011

would probably need some 2x4 tube, 1/8th inch sounds pretty thin but it might work...just be ready i think i just paid about $100 for a stick of 2x3 3/16's

strvger · Feb 10, 2011

think i'd go with 3/16ths just for those that might want to do some mods like front/rear hitches, heavy duty suspensions pieces, etc.
but that's just me.
great idea though! hope it's doable for sure.

cammeddrz · Feb 10, 2011

1/8" is ok (most stock frames are 1/8" or even thinner, and c-channel not box) but you will need fish-plates with rosette welds wherever you have the joints to make the frame have shape/angles, avoid doing 90-degree welds whenever possible (mine has 90-degree welds and has held up this past year and a half) so cut all joints on angles when you can

if you made a frame out of 3/16" mild steel it would be heeeeeeeaaaaaaaaavvvvvvvvyyyyyyy. and would have zero flex and therefore prone to cracking. if you are set on 3/16" you would need to go with chromoly so that the strength would be there, the flex would be there, and it would be lighter than mild steel by 35% or so, so it would weigh the same as a 1/8" mild steel frame

crawlin91 · Feb 10, 2011

anything wrong with the current frame? why not just pull the body clean it up and box it in with some 11 gage and new crossmember supports that can either bolt back on or be welded. Dimensions stay the same and aftermarket parts bolt on like they should. Just weld it in sections so the heat doesn't warp things. Cheaper easier to do IMO. Only major mod would be to the drivers side frame rail up front for the new steering box.

Check out JeepRecoveryTeam's crawler on tons build as he is building his own frame based on the original ranger design, similar to what you have described.

basilfaulty · Feb 10, 2011

crawlin91 said:
anything wrong with the current frame? why not just pull the body clean it up. Dimensions stay the same and aftermarket parts bolt on like they should. Just weld it in sections so the heat doesn't warp things. Cheaper easier to do IMO./QUOTE]

+1
Use your original frame and box it if only in certain areas if you need to make it stronger. Square tube would not work out so well...every where something is bolted you would have to put a boss in or when you tighten it it will crush the tube and never really be tight and will weaken the tube. Also every where there is a cross member, body mount perch or something welded to it you would have to cut the tube open slide the cross member in and weld it to both the inside vertical and the outside vertical or to the top horizontal and bottom horizontal, if this isn't done your stress would only be on one edge and wouldn't transfer through to the outside edge. It would either tear the wall out at the weld or twist the square tube out of shape. Also frames aren't entirely mild steel, they are whatever alloy the manufacturer specifies...they have a certain amount of hardness to them, alloying them to flex without breaking and still remain rigid. Pickup frames are different than explorer frames due to the amount of flex needed for a pickup vs an SUV.

If you have a later model truck or a truck with airbags it gets even more complicated. Anything your add to the structure, push bars, bumpers, etc. WILL change airbag timing and possibly injure or kill someone. Frames today are engineered to react a certain way in a crash to transfer energy away from the passenger compartment and passsengers. Any change will change the way the vehicle reacts in a crash and where the energy is transferred.

Some modern frames CAN NOT be welded or even heated past 800 or 900 degrees for more than a limited amount of time as the frame would lose it's structural integrity and thus be JUNK. Some modern frames can't take any heat and must be repaired COLD! Even hitting them with a hammer and dolly can "work harden" the area and change the integrity of the frame.

Unless you are using the vehicle "off road" only I wouln't modify your frame.

cammeddrz · Feb 10, 2011

basilfaulty said:
Some modern frames CAN NOT be welded or even heated past 800 or 900 degrees for more than a limited amount of time as the frame would lose it's structural integrity and thus be JUNK. Some modern frames can't take any heat and must be repaired COLD! Even hitting them with a hammer and dolly can "work harden" the area and change the integrity of the frame.

however true, as far as i know this does not apply to any rbv's

Tony Raine · Feb 10, 2011

thanks for the input everyone!

cammeddrz- i talked to a few people at work today that have made/repaired frames, and they gave me some good advice that would eliminate the need for fish plates. basically, you cut then end of one piece of steel into 4 separate sides. squeeze the sides in on piece #1, and insert into piece #2. then take the top and bottom portions of #1, and fold them over #2. a little measuring will get as much of it to "overlap" as possible. then i can weld together and add some plug welds as well.

crawlin91- no, the stock frame is actually in decent shape. i even have a "spare" frame (and body). problem is, the stock frame varies in dimensions so much, its hard to take measurements for all the "not stock b2" parts i am adding.

for example, that big ttb crossmember is a pita for a v8 and sas.

basically, i will continue to build off my current frame. everything will probably be fine for what i use it for, but I am always looking to improve.

plus, i will be able to drive my b2 while building its new frame. with better reference points, i can make everything line up much better than i ever could before. it will be stronger, easier to work on, and easier to modify in the future.

basilfaulty · Feb 10, 2011

cammeddrz said:
however true, as far as i know this does not apply to any rbv's

Depends on the year, some of this stuff goes back to the early 90's. (crumple zones, HSLA to a certain extent, airbag timing...the heat stuff not as much until the 2000's) just wanted to make people think is all. I saw a picture on here with a solid bracket welded across the crumple zones in the front frame rails for a custom bumper. That would definately change energy transfer and airbag timing! And that was on an early 90's RBV.

cammeddrz · Feb 10, 2011

Tony Raine said:
thanks for the input everyone!

cammeddrz- i talked to a few people at work today that have made/repaired frames, and they gave me some good advice that would eliminate the need for fish plates. basically, you cut then end of one piece of steel into 4 separate sides. squeeze the sides in on piece #1, and insert into piece #2. then take the top and bottom portions of #1, and fold them over #2. a little measuring will get as much of it to "overlap" as possible. then i can weld together and add some plug welds as well.

I did that on mine, i overlapped 3" on mine, mine is 6" channel that has 24" of weld on each joint, and no fish plates

but one of the "tech advisors" here jumped on me for the way i did it, but like i posted it has worked fine for the past year and a half

Tony Raine · Feb 10, 2011

basilfaulty- excellent points, all of which are appreciated. I would NEVER try this on a newer vehicle, or something that would be seeing highway miles.

my "speed goal" is good handling and control at 55 mph. after all, thats what the rig was designed for by ford back in '84. I have a newer truck and my wife's car for DD and highway driving.

I guess I should have stated my intentions for the rig:

-no more than 55 mph
-bad weather driving
-local "sunday drives" (cruising around in something "outside the norm" is just plain fun)
-fishing and camping
-and of course some good legal 'wheeling

Beanmachine7000 · Feb 10, 2011

http://www.expeditionportal.com/forum/showthread.php?t=49378&highlight=safari+pacific

Not exactly what you are doing, but some good stuff in there...

strvger · Feb 10, 2011

thanks for the link, beanmachine. excellent work being done there. bookmarked it so i can follow along with his build.

kimcrwbr1 · Feb 10, 2011

Ask Guaii he could make it fly around the sun and back.

Tony Raine · Feb 15, 2011

crawlin91 said:
Check out JeepRecoveryTeam's crawler on tons build as he is building his own frame based on the original ranger design, similar to what you have described.

Now that's what i was looking for. I'll keep up with that one :icon_thumby:

Building frame from scratch? Input desired

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