Bodyshells weigh  less than 750 lbs bare.
1/8" wall thickness is plenty strong.
I made the spider and door opening braces for my vert from 1/16"
wall 3/4" square steel tubing.
no movement when installed on Rotisserie.
For full body carts VMF site has a few threads with great Pics.
Cman

Last edited by cman66 (7/20/2021 6:00 PM)

Welding classes will teach you how to weld, but what you're talking about is more engineering.  They aren't going to teach you that kind of stuff.  There are some good books on the subject.  You need to know how the material is being loaded and with how much weight and then you can use tables and calculations to figure out if its strong enough, how much safety margin it has, etc.

This is all pretty academic, the weight you're talking about isn't much.  1/8" thick material is plenty strong.  1/16" is probably fine honestly.

Let me be clear on exactly what you are doing.  Are you looking to build a rotisserie or just a cart to move the body around without having to have an axle, and suspension under it? 

TKOPerformance wrote:

Let me be clear on exactly what you are doing.  Are you looking to build a rotisserie or just a cart to move the body around without having to have an axle, and suspension under it? 

Just a cart for now I'm not planning on building a rotisserie. Id like to build one but done have the time for that. I do plan on purchasing a rotisserie I'm thinking. Really a cart to move the body around with out the axle would be ideal. Id kinda would like something simple to move the car. I do Like thishttp://store.uscartool.com/1965-1971-Mustang-Car-Moving-Body-Wheel-Set_p_88.html or https://linksharing.samsungcloud.com/yvCijvid7G3P

but I think I could definitely make it cheaper but. Would like suggestions on material thickness though.




Plus I need to Build a chassis jig to do the rust repair. A chassis jig with casters to move the car around if needed and to do the rust rapair work would be ideal.

I was thinking 2x2x1/8 wall square for the 16' length runs and as well as my horizontal connectors to the body, 2 1/2 x 2 1/2 x 1/8 wall for female couplers. I was looking for help or suggestions on this. I was planning on mounting under rear leaf sping mounts to do frame patch under the front leaf spring mount under the rocker just forward of the front leaf spring mount then under the rocker  by the Hinge pillar post. Then one more mount which would attach in the LCA mounts. Probably really over kill.

I need to install rear frame rail patches floor pans full driver side transition panel trunk panels rear floor exstentions front floor extensions fix or replace the floor supports.install the new Rear shock mount and quarter panels.


Basically 2 parallel horizontal square tubes 16' then a 6'L x 5' box on top that mounts under the rockers. Then 4 5'horizontal bars one under LCA, two more under the leaf spring mounts front and rear.

Last edited by True74yamaha (7/21/2021 11:15 AM)

So moving the body around intact and a jig for making extensive repairs are two pretty different applications.  A cart can make use of the inherent strength in the unibody, and thus can get away with being made from smaller material since basically its just being point loaded (downward pressure only).  Basically you are making a roller skate for each end and trying them together to prevent them from kicking out as you roll it.  1-3/4" square material will be fine for that at almost any wall thickness of 1/16" or more. 

For a chassis jig you need something that won't allow movement as you remove structure from the unibody.  For that I would want chassis rails of something like 2x3 rectangular tubing with a 1/8"-3/16" wall thickness to prevent flex.  That's typically what most custom built hot rod chassis use for main rails, so it should be plenty strong. Then build the tie in parts accordingly.  The big thing is thinking about which direction you need to maintain a critical dimension and bracing accordingly.  Maximum strength is always going to be achieved with triangulation.  You can make a chassis jig so it can roll, but in the place you are working on it you want it set perfectly level.  Such a setup may be best with 6 casters for added center support under the rails.  If you use locking casters you can then place shims under them as needed to achieve true level.  Or jack it up and set it on blocks and shim the blocks to prevent movement. 

Last edited by TKOPerformance (7/23/2021 4:57 AM)

TKOPerformance wrote:

So moving the body around intact and a jig for making extensive repairs are two pretty different applications.  A cart can make use of the inherent strength in the unibody, and thus can get away with being made from smaller material since basically its just being point loaded (downward pressure only).  Basically you are making a roller skate for each end and trying them together to prevent them from kicking out as you roll it.  1-3/4" square material will be fine for that at almost any wall thickness of 1/16" or more. 

For a chassis jig you need something that won't allow movement as you remove structure from the unibody.  For that I would want chassis rails of something like 2x3 rectangular tubing with a 1/8"-3/`16" wall thickness to prevent flex.  That's typically what most custom built hot rod chassis use for main rails, so it should be plenty strong. Then build the tie in parts accordingly.  The big thing is thinking about which direction you need to maintain a critical dimension and bracing accordingly.  Maximum strength is always going to be achieved with triangulation.  You can make a chassis jig so it can roll, but in the place you are working on it you want it set perfectly level.  Such a setup may be best with 6 casters for added center support under the rails.  If you use locking casters you can then place shims under them as needed to achieve true level.  Or jack it up and set it on blocks and shim the blocks to prevent movement. 

Thank you for the insite on the roller body cart with downward pressure.  and the suggestions on rails for a jig I like the idea of the 2x3 much better than the 2x2 and 2 1/2 combination I would like to make one that has levelers and casters. That is what I was thinking of including in my chassis jig.

True74yamaha wrote:

6sally6 wrote:

6sally6

He he ill try and think smarter not harder thank you. Really need to get some metal and get welding to gain more experience

Didn't mean that in a bad/ugly way! Jus try'in to be hep'ful!
6s6
 

6sally6 wrote:

True74yamaha wrote:

6sally6 wrote:

6sally6

He he ill try and think smarter not harder thank you. Really need to get some metal and get welding to gain more experience

Didn't mean that in a bad/ugly way! Jus try'in to be hep'ful!
6s6
 

None taken Like I said earlier I really appreciate all the advice frome everyone. It never even made me a little upset with your statement. I'm always a downer getting my car on a little chassis jig or a body mover to start will be a big confidence boost. And not to mention a huge start in the right direction PUN intended to getting metal work buttoned up and on to body work done. Like I stated above I really appreciate everyones help and and insight they give me I mean I do realize I'm the youngest amongst the group so tons of chances to Learn Tons of information.

You probably know this already but don’t use galvanized tubing. Welding galvanized materials produces very toxic gasses.

Yes, 0.120" is just a tick under 1/8", which is 0.125".  That would be fine. 

On welding anything into the existing unibody be aware of a couple things.  You don't want to use material that is too thick, because its hard to get a good weld between thick and thin material.  You tend to either make a weak weld with bad penetration on the thick material, or burn through the thin material.  One trick is to weld a plate of intermediate thickness to the tubing where it welds to the body.  This allows you to more easily weld the plate to the thicker material and then the plate to the sheetmetal of the body. 

The other thing is wear a respirator.  The underbody in these cars actually had some kind of galvanizing applied to it at the factory.  You'll need to grind through that to get a solid weld and can still create toxic fumes when welding because the zinc is impossible to fully remove mechanically. 

The tubing doesn't have to slip fit tightly to make it adjustable.  In fact that may  not work out as well as you might think depending on how tight it is (it may not move easily).  Another option is to just drill a series of holes and use pins or bolts.  If there's a gap it won't matter.  The weight will be born by the bolt or pin.  Something 3/8" in diameter would be fine.  They use 1/2" to bolt the structural steel together that holds up a house.  Just use a drill press to make sure the holes are nice and straight so you don't have to fight with the bolts/pins.  Go a little larger than the bolt/pin size too, like another 64th" so you don't have to fight them going in and out.