So I designed this cart for the body while I continue my so-far year long body prep for rust repair and restoration... all suspension is still attached. My design is 24 inches high. My jackstands lift the car to 17 inches. I needed 7 more inches - what was i thinking! it was VERY scary lifting the car and jack stands at each corner with 2x4 jack stand supports and jack pad/height "enhancer" LOL

Here it is. I'll get pics of the car up on it later.



I'm pretty sure it is MORE than strong enough to hold the car up. The castors I bought however may not be good enough as it is VERY difficult to move the car. They are each rated at 300 lbs. I guess it weighs more than 1200 with the suspension still on?

Can somebody take my autocad file and do an computer structural analysis on it?
ACAD FILE

your casters are also carrying the weight of the dolly/cart.

300 x 4 casters = 1200lbs....

car weighs about 2000.... + cart

I like it but I would go with 4 x 4's for the bottom members. Those 2x 4's on thier side are weak. All the weight is being carried by them. Good use of diagonals.

As for the castors, they seem a little under-sized, but if you don't plan on rolling the car around much they may be fine. A failure of the cators would probably not be a ctastrophe, just a PITA. But it wouldn't hurt to upgrade em just to be safe.

As for the structure, I would worry a little bit about all the points where the 2x4s join. Not much "meat" there to start with, and a screw/nail near the end of a 2x4 can weaken it significantly - especially if the wood is old or dry. Don't forget, you're looking at forces on each joint that are much, much greater than on house framing. I agree that I'd probabl;y use 4x4s at least for the bottom square.

Another thing that would strengthen the design a whole lot would be a skin of plywood screwed onto the 4 vertical surfaces. This "stress skin" design gives a lot of protection against distortion, as do the diagonals, but it also helps hold the two pieces on either side of a joint tightly together. The plywood doesn't need to be all that thick to provide a lot of strength.

I agree, plywood=good.

Even 1/4" screwed on the outside every 3" would really tie it all together.

Add some wood glue to the plywood/screws idea.......extra strong

As said, 4' X 4" on the 2 ends that hold the weight.......

Car without motor/trans about 1600 lbs

Since nobody else posted it..

Is it safe to crawl under after i get the suspension off? Who has procedures for the front? I assume i should release tension on the torsion bars first what order of removal is suggested. Thanks. also, are they 22mm rear nuts on the trailing arms? I need to go by the larger metric set. I only have up to 19mm

When planning I decided that I didnt need 4x4s at the bottom beause they were essentially just tying the legs together. Laid down they are only under compression weight from the 2 "t'd" 2x4s that are 17.5" vertical under compression down to the wheel.

I also modified the diagonals for the small insides so i didnt have to calculate angled cuts on the 2x4s. I only have a hand held 19.2v circular saw not a table saw which would have made that all a bit easier and faster. i just turned em and cut em to length to wedge in instead. probably sacrificed a bit of strength but it is very stable and doesnt rock or sway at all when i jiggle it with the car on it.

My only worry is that the car does not sit flat on the cart, the front doesnt rest on the donuts but on the center tunnel, so i think i should shim that?

And it almost seems like the body is twisted along its front to rear axis by about a 1/2 inch. when i put it up on the jackstands, it would rock from drivers front to passenger rear... well, i just remembered that the rear donut seems bent into the long a bit. maybe thats it. i also think i bent the long in a tiny bit lifting using a 2x4 flat to spread the weight but just inside the donut at rear. I'm not going to worry about it all too much... tell me if maybe i should.

I didnt want to put plywood on the outside due to restricting me access to clean the underbody then.

what is the color on those rockers L96 b?

some one cut of the tops of your front qtrs

Like the others said, the casters are a little undersized.
As for the support, NICE carpentry job !!!.
No problems for the safety factor. I would`nt be afraid to crawl under.

Steph

it looks like the 2x4's are bowing... (bottom sides..)

That looks like a cool idea for winter work in the garage
Is it safe? Plan for the worst. You are under the car and have a 4 foot breaker bar turning 300 lb torque and the front caster rolls into the crack then breaks off, will the structure fold and collapse? The cross bracing needs to be strong, and yours looks minimal for side to side flex. Through bolts, nails, screws, or glue or all? If you *search* threads started by SirAndy, you will find pics of a seriously twisted teener. His had lots of fiberglass body panels too.

Hehe, ya, all the quarters are a bit shorter than stock. shalom. chalon. whateva!
Not sure on the color, a very pretty color though where its not painted over and still fresh. I think it wasnt a really really popular color though because a porsche purist really frowned when he saw it under the white... i made sure to let him know the PO did all the mods.




Nope, not bowing at all. Some of the 2x4s are warped and I had to pull them into straight as much as i could. I had some difficulties with some.




Well... it ACTUALLY ROLLS now... with all suspension off of it it is fine now. not like its on ice sliding or anything but it is easy enough to move and goes over the garage cracks ok. I just used 2 1/2 inch screws all around, most joints have multiple from different angles and sides of the wood. It is very sturdy now even moving. before with all the suspension on it, it was actually still solid and didnt wobble at all. but by knocking on each leg i could hear the pressure bearing down. tight with no resonance vs the other cross bracing which still resonated like a regular 2x4.

If i were to build it over again. I would use larger castors, make it a bit shorter and take the time to use wood glue and be a bit more precise with my cuts. I would have done my cross bracing just like the design too vs the improv'd way i ended up doing it.

here are some more pics. I'll put together later full out dimensions and supply list for future builders too.


NOTICE the passenger is off the wood by an inch or so... not sure if this is because my cart is crooked, my garage floor is crooked or the body is crooked. OR if its just because the center tunnel of the car is resting on the 2x4 cross brace in the front instead of on the donuts.

bump for thread topic change...

Are you sure your cart is square? Theres a good chance those casters are going to fold under that weight.

Also, next time you need help, put out a request. I would have helped you lift that thing. I'm sure we could have got enough local guys to do it.

yupp, looks tweaked ... did you install the body kit? if not, one of the most common reasons people install a FG body kit is that they have insurance money to spent after the car was hit in an accident ... ask me how i know ...



good news, nothing a celette can't fix. bad news, that won't be cheap ...
Andy

Looks like the floorpan is buckled up wher that donut is, maybe from the car being jacked up by the floorpan instead fo the donut. The tub look a little tweaked too. I would check to see if the cart is square/level.

Oh and the corner that is off the cart may not be the corner that is bent, could be the opposing rear corner as well.

does look a little 'off'. how does it compare in measurements?

http://www.914world.com/specs/bodydims.php?...5e8c2a26a20e538

http://www.914world.com/specs/underdims.php...5e8c2a26a20e538


btw, i would have really built that cart out of rectangular steel tubing...

Material: Douglas Fir
Modulus of Elasticity: 1950ksi
Tensile strength (ultimate): 340psi
500lb loads at each top corner on 3.0in dia area (102psi)
Area moveable support at each bottom corner over caster mount plate area.

It looks like you're barely stressing the thing.

I bought the car as is, it doesnt look like it was hit anywhere else... but who knows. Its only off from flat by about 3/4. I will get out the level, maybe its the garage floor and the cart is flexing to follow.?



I cant weld and I think wood is cheaper than steel isnt it?



THANK YOU!!! That is what I suspected, now its confirmed. I apreciate you putting that into your system for me.

How'd you get it up there?

10 inch 2x4s laid flat and screwed together in a square overlapping tower (2 in each level - five rows high) to put underneith my jackstands lifting them 7.5 inches higher under the rear control arms. The front rested 17inches high on 2 jackstands while i alternated left to right at the rear to get the stands high enough for the rear donuts to be 24 inches up.

Then i screwed another few 2x4s together to lift the under the front crossbar to get the front dounts high enough with my jack so that i could slide the cart underneith it.

I worked very slowly and carefully. It would have been smarter to remove the suspension while it was only on the jackstands and lower to the ground.

I'm not sure 4 guys could lift this car 7 extra inches. Not with fiberglass fenders which cant be used to lift from.

I'll invite all you az guys over when i start putting it back together --- unless you all want to help start sanding it down.

a little closer look at my "twist" --- probably not actually twisted.

Looks like once upon a time a PO jacked the car up in the wrong spot and bent in the floor and tilted the donut up and in with it. I now remember last year when i was stripping the floor that it was not flat... but previously I had assumed that the curve in the floor was stock. (yup, sometimes I'm not the sharpest knife)




also, a few more pics of the car up.

Hey, that sounds like good news!
We do so much to our cars how can you expect to remember every detail.

anybody want to give their opinion on the best approach for straightening that back out and down?

big peice of wood and sledge?

Yes. Thats exactly what I would do. I might even try without the wood and with a slightly smaller rubber coated hammer.

Go to harbor frieght and pickup a dead blow hammer. it is a rubber hammer that has a bunch of lead shot in it. Use that on your floor and that should get you back where you need to be. You will probably have to shrink the metal where it stretched -but the hammer technique might get you close enough.

use a 2"x 6" block on the floor. hit the block with the dead blow. You'll move more area and have a better chance at flattening the floor.

WOW Marty that is cool! Now how would that design hold up to a NorCal 6.5 - 7.0 earthquake? Major progress! I am guilty of being an armchair critic, I think that cart is going to be fine. Did you *search* for the SirAndy thread where his car is put on the torture rack? Very cool pics. Good luck

yup, saw the majorly twisted teener... his license plate should say TWISTED!

The cart is fine, its the castors I shouldnt have tried to save $ on. Should have got the 4 or 5 inchers instead of the 3" ers. Ill probably throw 2 more 2x4s on the bottom and then get bigger castors. anything over 3" wont mount on a 2x4.

Thanks all you guys for your help and criticism;)

A note to remember when building jigs like this or putting a new beam in the basement to replace a sagging floor.

Strength is increased with height. For solid objects, base times the height cubed. so for a 2x4 flat is 1.5^3 times 3.5 = 11.8125. On edge, 3.5^3 times 1.5 = 64.3125.

So on edge a 2x4 is 5.444 times stronger than it is lying flat. I know that someone will check my math. It's stronger, you know it is.

Gussets and adhesives will stiffen and add safety. Plywood on the faces where access is not needed will really make it strong.

Just don't add drawers, entertainment center, mp3 features or you will never get it off of the stand.......

Cheers,

Fin