chassis jig design

[LS1MonteSS]

Will,
The guy you saw assembling that chassis is the owner Art Morrison.. There was a whole article series run in one of the car mags that showed the whole process as he built the chassis and car..
Looking at your design picture for your chassis jig.. I would think that if you added a few cross braces bolted to the main cross bracing, you could easily use 3/5" to 5/8" plywood as a top for your jig.. I have seen 3/4" cabinet grade plywood support a point load of 400+ lbs, the cross braces I mentioned will push that up as long as the distance between them isn't more than 2'...



When I used the plywood as a top for my old jig.. I found the best way to secure any bracing was to make backing plates with bolts welded to them. Run them from the underside of the plywood and make a brace with feet so they can be bolted down to the plates. You may be thinking how would you keep that all aligned?...

I would lay out the lines for my chassis on the plywood top, locate the points I wanted the bracing or blocking, cut (let’s say for simplicity sake) a 4”X4”X1/4” plate and drill two 3/16” holes in each plate and chamfer the top of the holes, place the plate according to my layout, then screw them down temporarily to the plywood top with 1” drywall screws… Then I would figure out the heights for the braces and supports and use 2”x2”x3/16” box tubing, cut those to the specific lengths needed and place them where they go according to my layout.. Now there are two methods I used for the base of all the braces/supports.. (1) Use a length of 1 ½” X1 ½” X ½” angle iron for brace/support feet (not less than two per) welded to the bottom of each brace/support.. (2) Cut 4”X4”X1/4” plates and weld them to the bottom of each brace/support…

Once you have figured a method for the braces/supports feet, drill at least two ½” dia. holes on opposite sides… Place the brace/support back over the plate you fastened to the plywood with drywall screws and mark the location for the ½” holes you drilled in the bases for the braces/supports then drill out the plates right threw the plywood… Now you have located the plates where they go on your jig and all the holes will line up when you’re ready to bolt the braces/supports into place for your project… Weld two ½” bolts to the base plates from the underside of the plates and your all but ready t start working on a new frame/chassis..

Being that most guys end up doing a lot of projects alone for the most part… Remember the two 3/16” holes you used in the base plates to locate them on the top of the plywood? When your under the jig you can use the same 1” drywall screws to hole the plate in place on the underside of the jig while you bolt down the brace/support to the top of the jig..

Yes, making of the braces and plates takes some time, but you only really have to do it once. Now you can use them for any project with little or no modifications.

That was my way to do it, but there are a million ways to skin a cat..

Hope this helps or at least gives you some ideas!

Kevin