chassis jig design

[raustinss]

Hey guys as a professional fitter /fabricator I've made a living on a 4x8
1" thick table it had 3"angle legs with spreader bars obout a foot from
The bottom and more about 5" from the underside of the plate surface
Keep te legs in about 4 " in on the sides and about 18" on the ends . Now
If you can afford it machine the surface "flat" and tap 1/2" holes all over the
Plate . Roughly a 6" grid . These holes will allow you to bolt on "risers"
And hold downs . These can be welded (tack) to the car and bolted down
To hold everything in place while you work. DO NOT rely on gravity to hold
Steel and shims as steel moves when you weld and hammer. A light coating of oil
Will prevent splatter from sticking and rusting.the problem with I beams which are
Actually called wide flange is they aren't true the web (center) can be off center
And they can twist . Tubing is really nice it is at least nominal . (diamenstionally) true This makes measuring easier . I personally would make mine out of tube or the above
Table just make it 10'-12' long. The benefit to a "plate" surface is you can write and draw on it and have somewhere to place your tools.
Any questons email me [email protected]

[LS1MonteSS]

I know this is a old thread...
Back when I was still in the Army and station in Germany (Mid 90's) I ordered a Art Morrison 12 point chassis after seeing the build he did on a 55/56 chevy race car.. He built the whole thing off of two sheets of 3/4" plywood tied together.. Not sure if any one else saw that build or not..

My plans for a chassis table are two 8"X12'X.125 thick "I" beams, spaced 4' apart and the tops will have 12"X12'X1/2" thick plate.. I figured to make the legs out of 4" square post roughly 3' long, 3 per side and adjustable feet to level it to any surface. I'm a tall guy so all that bending has to go and the height will let me get under the table to do any welding.. Add three 4"X4" cross ties bolted to the "I" beams but levet with the top surface and 2"x2" angle bracing tying things together.. I will make out riggers to at the points where I need to work the suspension which can me adjusted depending on the wheel base of any given project..

[wellis77]

Glad this was recently brought back up. I'm going to be building a table for myself in a couple months and have recently been thinking about the best way I can weld this together to avoid warping. I've read through this thread many times and have read about bolting top rails to the frame of the table to avoid warping but I'm having a hard time picturing what that looks like. Does anybody have pictures of this type of design to give me an idea?

Otherwise, what are some ways I can avoid warping, as much as possible. Until earlier this week, I figured I would stitch weld 1 - 1 1/2 inches per leg, then about an inch on each side of the 2 x 2 cross braces. From other threads I've read that seems to be a pretty common way of welding a table together. Earlier this week I found some "welder angle clamps" and it got me wondering if this might be a better option. At $40-$50 a piece plus shipping, they aren't cheap but it may be worth it in order to be certain. Any thoughts on these clamps and if they would be worth the investment for a one or two use table?
http://cgi.ebay.com/4-Industrial-Wel...#ht_2871wt_907


Below is an image of my design so far. I'm planning a 15' table with the side rails out of 3x3x1/8 box tube, cross braces and angled leg braces out of 2x2x1/8, legs are 2x3x1/8. I'll be building adjusters into each leg in order to level it out.


I appreciate any feedback on my design and questions. Thanks everybody.

[LS1MonteSS]

Will,
I know the length for my legs might seem long but appx 12" of it will get used up by the I-Beam and top and that still affords me some room to get under and around what I'm working on.. I like your table design, it would be an awesome set up if your plating the top!

Kevin

[wellis77]

Thanks Kevin. I'm not planning to put a plate on top just because of the cost. I'd like to but I'm using this for just one, maybe two builds if I can talk the wife into another once this one is finished. My main concern at this point is how to go about welding this thing together to minimize warping. There has been talk about bolting on top rails but I can't visually that with my design so I'm not sure.

[LS1MonteSS]

I'm going to stitch weld my 1/2" x 12" plate to the top of my I-beams.. The welder has to be set higher to penetrate the plate good..

I figure if I put six or eight good tacks around the plate to the I-Beam.. Then start at one end and weld a 1 1/2" to 2" bead.. Then jump to the other end and do the same.. Giving things a reasonable time to cool it should be fine and checking that my top plate isn't bowing.. I'm thinking along the lines that a 1 1/2" to 2" bead then skip 3" or 4" for the next bead things should be fine.. Not something I want to rush into for sure..
The first one I made was based off the same ¾” plywood platform that Art Morrison used, except the did his on the floor and I built mine up on a elevated platform and bolted braces in place to keep things in line during welding.. The 12 point cage and frame I built for the Z24 Cavalier came out fine.. I also foll0owed Art Morrison’s advice and just put good tacks on all the frame joints, then pulled it off the platform and did my welding in locations all over the frame to minimize distortion and warp age… MAN was that A LOT of welding.. I had to mark where I had welded just so I would remember I had done something in that location and weld elsewhere so things wouldn’t warp on me..

[wellis77]

I have seen something in AME's catalog I think about a guy assembling a chassis on a piece of plywood. I would love to get away with something like that to save on the cost of a table but I really want to make sure everything is squared and aligned correctly and I feel like a table will help that process so much more than a sheet of plywood.

[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

[wellis77]

Thanks for that Kevin. I'll have to process this and figure out how I can make that work on my build. I appreciate your help.

[LS1MonteSS]

LOL... it is funny, as now I'm rethinking if I want to go with that again or not.. I'd have to start from step one as I sold the last jig I made to a friend.
If you want to do any brain-storming just shoot me a PM or post something in the thread.. I’m just like you.. Money is always tight!

[mike w.]

as i work with these chassis jigs daily i would just like to offer will ellis a tip with the design above, the width you have the jig set at can be a real pain in the but as you will always be leaning over the rails and although you probably made it this width to allow wheels to sit on it, it is more of a hindrance for a large % of the build, our jigs are 3 ft wide at the most and when we need to mock wheels up we place a couple of sq tubes across the jig to hold them, we weld bars from the outer edge of jig on an angle to tack to rockers etc, when working on a car with fenders removed etc the wide benches really keep you away from where you need to be, as for levelling we use 3/4 " bolts threaded into plates on bottom of legs, simple but effective, once the jig is squared up we cut a notch front and back on centerline so a thin steel cable (or string) can be pulled tightly and will sit in the groove so all dimensions can be taken from this point down the length of the car, hope this helps someone,

[wellis77]

Kevin, thanks, I may take you up on that as I get closer. I appreciate all your input.

Mike, that is some great advice. I hadn't thought about that. You are half-correct on the width, I set the width to the track in order to make it easier to mount my suspension jig with the hub fixtures sitting on the rail (the tires would also sit there though), but also it is the width of the inner rocker so I have a point that I can weld the body to the table. Once the floor and uni-body is cut out of it, all I have left is the rocker as a point to mount. Even then I'm a bit concerned at how that will hold up once cut out the inner rocker to replace it. Thanks for the confirmation on the notch for center-line. I have been thinking that is how I'd do it.

[LS1MonteSS]

Mike & Will,
I have been trying to remember why I sold off the first jig I built and it wasn't till I read both your postings that I remembered the reason..
For the 12 point frame and cage that I made up my Z24 Cavalier it was perfect in that the car was FWD and I cut out the whole floor pan and was building a new frame all together so I needed a flat surface to work from other than the floor.. The plans that came with my AME kit were so spot on that once the cage was done I just bolted the suspension into place and pulled the chassis off the jig.. The rest was all body work.. The flat surface of the platform jig I used made it easy to insure all my tubes were at the same angles because I could use the all flat surface to measure from anywhere I needed to..

My new project already has an established frame. So I need to do like Will and determine my ride height then use a suspension jig to keep things aligned… I started brain storming the best way to do this and still have freedom to get in and around all the things I needed to weld on and Mike’s type of jig made the most sense.. It seems kinda off at first, because the car seems to just hang there in the air. But some well placed 2x2 across the main jig rails and simple out-riggers for points needing support beyond the main jig rails will still afford the needed movement around the project and if things are bolted into place you can do all the mock up then unbolt it to finish off the welding then reattach it when needed.

Lou from the Spike TV show “Muscle Cars” made a cool suspension jig stand from 1” threaded pipe and plumbing fittings that held the spindles and rotors where he needed them while the worked on other aspects of the frame..

Will who did the rendering for your car? It is a sweet deawing to say the least!

[mike w.]

i will try and get a few pics tomorrow and upload them,

[LS1MonteSS]

That would be cool to see for sure!

[wellis77]

That would definitely be awesome. Thanks Mike.

Kevin, my rendering was done by Shawn Mascoll of Mascoll Designs. He's done quite a few here and on Lat-g recently. Very nice work and real cool to work with. Only difference between your build and mine, sounds like anyway, is I still need to build the chassis. I want to get the body on a table with the suspension jig, wheels, & tires, get the ride height completely mocked up, then build the chassis around it all.

Thanks for everything guys.

[mike w.]

at the shop the first thing we do is set the body up on stands at ride height with the wheels underneath to get a look at the car as it will be when finished, then we take lots of measurements at the front to the floor and front of rocker to floor, rear rocker etc etc, you really can't take enough!! then we mount the body to the fixture simulating the dimensions from the floor, double check its on centerline then weld it down to the fixture, we try to mount it in such a way that we can cut floors out and insert rails etc without the fixture being in the way, note in the pics it is far easier to work under the rear wheel wells without a wide fixture in the way, you would have to lean over or climb over the fixture every time when working this area,

[wellis77]

Are those 2x2 tubes just tack welded to the corner of the outer rocker? Are those four mounts the only places where the body is welded to the table? Thanks for the pics, those are great and will probably help lower some of my table costs. Any chance you have a pic of the full table? I really appreciate you sharing these, think I'll definitely be making some changes. Based on you experience, do you recommend a particular height or whatever is comfortable/fits? This thread just gets better and better. Thanks Mike.

[mike w.]

yes they are welded to the rockers, as these are very solid on this car, it also has two supports in the corner of the rear valance and two by the motor mounts, it is surprising how solid the car is when mounted this way, once the frame and heavier parts go in then they get supported too, i don't have a pic of an empty fixture but is basically as you see it in the pics, just two 4x4 beams with 3 crossties on 4 legs with adjusters on the bottom. The height is approx 28 " but that is to suit the average height of the guys at work approx 5'10" we build everything from promod dragsters to hotrods to musclecars on the same fixtures, if you need more pics you will probably find a pile of inbuild shots on our website where i work, www.lowdownhotrods.com, hope this helps ,

[wellis77]

Mike, thanks for all the info and the link. You've been a huge help! I went through most of the pics on the Low Down site and you guys do nice work. I'll be using some of that as reference for my build. I'm surprised that all of your tables have just 4 legs, nothing in the middle for support. Obviously it works but I was surprised to see it. In one of the pics where your lifting a car to the table, looks like your running a strap under the roof of the car and attached to a chain hoist on each side of the car, you have no problems with the roof getting distorted or bent at all when lifting from that point? I'm sure it's not hanging there long but one thing I've been trying to figure out is how to elevate my car to the table and that looks alot easier.

If you haven't already, you also really need to get some pics and specs of your Nova up. that car is HOT!!! Is that Snakeskin Green? Looks great and I would love to see more info and pics on the chassis and suspension.