Anybody see a problem with this jig?

kenrinc · 01-28-2005, 04:35 PM

So we built a wood jig to support the car during the restore and just wanted to make sure that I'm supporting it correctly so when I'm done everything lines up. I know these cars don't bend like 356s but it's good to be safe. Car is a 68 911L. Hard to see but the front is bolted to 4x4 posts that go up to the front suspension mounts. The rear also sits on 4x4 posts bolted to the inside banana arm mounts.

Ken-

Natchamp · 01-28-2005, 04:44 PM

Just a thought, you might consider triangulating those vertical 4x4's. Personally, I wouldn't want to put all my trust in those metal brackets alone. It is bolted down right?

Britain Smith · 01-28-2005, 04:58 PM

I agree with him, I would add some support to the metal brackets. Here is a picture of the support I built for my car when I was transporting it on a rotesserie. Same as yours except it was out of metal and no wheels.

-Britain

Britain Smith · 01-28-2005, 05:00 PM

Ah...yours in San Jose. I am in Milpitas. We should get together sometime and check out each others projects. Mine is a '69.

-Britain

jtratza · 01-28-2005, 05:07 PM

Think of this as a backyard deck. Now think of 10 buddies drinking beer and BBQ burgers. You don't need to put cross braces on this anymore than on your deck.

randywebb · 01-28-2005, 05:14 PM

decks now require cross-bracing for earthquakes.... that sort of translation and shaking might well happen from somebody pushing or falling against the car's side.

I'd X-brace it but not worry about the metal brackets - the sood itself is providing support vertically

Wood is a super strong material in certain directions. I wish we could make a composite like wood out of metal....

TXScott · 01-28-2005, 05:25 PM

I'd remove the cardboard box, I think that's kinda overkill

Seriously, though, I would use steel casters, I used small rubber ones like that and they developed flat spots real fast and it was a biosh to get momentum to move the car around.
Scott

Chuck Moreland · 01-28-2005, 05:32 PM

Unlike a deck, that dolly has wheels and will be moved around. You'll be introducing lateral loads. Even when stationary, when you work on it you'll sometimes be pushing against it.

Triangulate and don't be sorry!

Dennis Kalma · Dennis Kalma's Garage

This is a frame I used for my last restoration, worked fine rolling it around the garage and also was OK on a flatbed to the bead blaster...this is a pic I took upon its return....

Dennis

Zeke · 01-28-2005, 08:35 PM

Quote:

Originally posted by jtratza
Think of this as a backyard deck. Now think of 10 buddies drinking beer and BBQ burgers. You don't need to put cross braces on this anymore than on your deck.

Don't know if the car in the first post is gonna get any welding, but if so, all the cross bracing you can put on the stand will help. The wooden cart will flex if not on a perfectly level floor. Think of corner balancing your support system as a way of not introducing a preload to the tub that could take a set in the event of longitudinal replacement.

This is where a frame machine or jig like a Celette comes into play. Any loads created by bolting down to a perfect surface are good loads. The statement quoted is simply irresponsible. This has absolutely nothing the do with decks or beer and a statement like that comes from nothing but wholesale ignorance.

Natchamp · 01-28-2005, 09:06 PM

Zeke, thanks for saying what I was thinking.

David · David's Garage

Just add some cross bracing and you'll be fine, David Martin, PE (the state requires me to put that after my name when I make statements like that

)

wilke3169 · 01-29-2005, 04:07 AM

Even heavy metal straping as shown in Dennis Kalman's photo crossed and lagged to the uprights would provide stability.

blue82coupe · 01-29-2005, 06:38 AM

I wouldn't trust it with my life. A.75 inch plywood gusset glued and screwed into the uprights on either end of the fixture. Then add (2) cross ties between the uprights.Again screwed & glued.Dan

turbo6bar · 01-29-2005, 06:59 AM

Quote:

Originally posted by jtratza
Think of this as a backyard deck. Now think of 10 buddies drinking beer and BBQ burgers. You don't need to put cross braces on this anymore than on your deck.

In my area, the 4x4 posts of a deck are inserted into the ground. This resists the moment acting at the deck surface. The pictured strong-tie post base is not designed for a bending force.

I agree with other posts. Add cross-bracing, and you'll be good.

widebody911 · widebody911's Garage

Are you going to wet-sign that post?

Quote:

Originally posted by 125shifter
Just add some cross bracing and you'll be fine, David Martin, PE (the state requires me to put that after my name when I make statements like that )

makaio · 01-29-2005, 07:22 AM

Quote:

Originally posted by Dennis Kalma
This is a frame I used for my last restoration, worked fine rolling it around the garage and also was OK on a flatbed to the bead blaster...this is a pic I took upon its return....

Dennis

Dennis, is your jig bolted together? It appears that way in the picture. Do you have the measurement, or would you mind sending me the measurements?

Dennis Kalma · Dennis Kalma's Garage

This jig is entirely bolted together, and unfortunately, I sold it a while ago. I built another one for the '79 project that I ended up selling and in a pinch I could ask the buyer to measure it for me....which measurement in particular do you need?

When I built it I actually just did rough measurements off of the car, had the metal place cut everything to length (cost like $1 per cut) and drilled/assembled it as I went. Wasn't too tough to do, took an afternoon to get together.

And yes, it is/was strong, stiff and I felt no angst about crawling around underneath it. Only real problem was getting the tub up high enough to get it in underneath. Took some blocking and jacking which was a bit scary...

Dennis

makaio · 01-29-2005, 08:08 AM

Thanks Dennis! I can do the rough measurements, I was just trying to save myself the trip to the garage.

Dennis Kalma · Dennis Kalma's Garage

Hey Britian....can you make any comment on the rotisserie that you show in the pictures? I checked out your web site, lot of useful views in there, but I was wondering whether you found any problems with rotating? I'd be worried that it wasn't clost to being balanced and it would be a pain/heavy lifting to rotate it?

Also, I was thinking of using the bumper brackets on my '89, they appear strong enough, but did you have any worries about bending the chassis with teh car supported at both extreme ends, I assume you were crawling around inside of it etc etc....

When I do the math, a 3000 lb Carrera, take off about 700 lbs for engine, 200 for wheels and tires, probably another 200 lbs for suspension, call it 500 lbs for doors, hoods and bumpers, I am guessing that the stripped tub probably weighs in at about 1000lbs or so.....it ought to be strong enough to take it, but does anyone else have any data or thoughts?

Dennis Kalma