I have an old welding table that I am making into a frame jig. The table is 28" wide X 108" long. Its built out of 2x4x1/4" tubing. I tacked in some 2x3x1/4x 60" cross braces. This is for a 33 Ford project I am just getting started on. When setting the frame up on the jig do you set the frame level or, do you try to set it up at ride height? I'm in this process now and think I should set the frame level.
I'd have the jig level and the frame set up on it at ride height / angle. That way everything is correct to the real world and no corrections need to me made, eg when setting caster. Chris
Everybody I've ever seen set the jig level at a comfortable working height. Every measurement was referenced off the top of the jig and was made level, square or plumb as often as possible. It also helps to have a centerline, and the frame centered in the jig. Castor, camber, ride heights etc are all adjustable and were set before going to the track. Good Luck
The jig needs to be level..........period ! The frame needs to be set up just as it will be when driveable. The front suspension needs to be installed with the frame on whatever plane it will be on when you are driving. If you weld the suspension mounts in with the frame level and then put big tires on the back, you will change the caster. The mount needs to be welded in to accept the suspension without any bind and sitting in the exact position to accept the spring and still maintain the correct caster. I would get the tires and wheels you are going to use and place them on the table and find their center so you know exactly how to assemble the frame and suspension. Remember that the weight of the engine and body will compress the tires somewhat.
IMO... set the flat top of the frame rails level... the front of the frame from the door opening forward raises as it flows forward... you will need to be able to measure from the rails down to the table, so set it up level... might even check the frame for square before you weld anything...
Table needs to be horizontal in both directions, length and width and at a good working height above the floor. I set my frame rails up parallel to surface plate (Datum line). The frame needs to be checked for lengths and diagonals to enure that it is square before you fabricate any support bracing. Once satisfied run a string for centreline and double check measurements. When setting up front and rear axles each sides measurements should correspond ensuring squareness to centreline and correct wheelbase, we don't want any nasty surprises later with any strange harmonics or poor handling due to suspension bind and incorrect geometry. I use multiple corresponding witness marks (Rivets etc) that I drill with an 1/8" drill enabling frame to be trammelled up. In saying that I did a friend's 33 frame years ago that looked OK to the eye, only to establish after trammelling it that up that one side was flat compared to the other. It required some massaging and cross bracing to get square and correct. Fortunately he hadn't welded in his new X-member as it would have been out! Measure twice, cut once!
It’s up to you. I do frame work(straightening) with the car parallel to the frame bench. I set up a hot rod at ride height and rake. build it like its gonna sit has never failed me.
My table is level, at 'ground' height in referance to the car/frame. I make fixtures to hold the front axle (by the spindle snout) and the rear axle - those are fixed points assuming you know your tire size. Then I make as many other fixtures as needed to hold the block, trans etc. I tackweld the fixtures and arrainge them so the device I want to hold is bolted in and can be removed/replaced back to that same spot. Keep in mind you'll be putting it together and taking back apart a bunch so you need it to be as solid as possible, you don't want to recheck yourself after a couple weeks to find something has shifted by 1/4". I use a 3" diameter tube that bolts/slides into the pinion support and travels up to the front crossmember, riveted to the top is a 120" ruler that acts as a straight edge for your square. That won't lie, you bolt it in from time to time and recheck yourself and that'll tell you how well you made your fixtures.
Have table for sale...built lots of cars on it...has lots of tooling. Needs to be rigid, levelable, and rollable and infinitely adjustable. Mine for sale is easily move, covered and put outside. Floor space is always premium. Sent from my XT1710-02 using The H.A.M.B. mobile app
Well, the frame jig is occupied at the moment, they are pretty straight forward anyway. Here's some pics the jigs I use to hold everything, some look crude as if they were made from scrap pieces because they were made from scrap pieces, but they do work good: The 2 in front are able to move up and down the jig rails, they are handy to clamp the frame rails to hold them while you work out the crossmembers, it takes a few sets of these, just forged C clamps with one end cut off and welded to an upright, the open box end at the bottom is to clamp it to the chassis jig, you'll need to move the up and down the jig so I don't tack them. The next 2 are fixtures to hold rear ends, can't remember what the closest one goes to, its very short, the rear one is for a 31" tire, 3.250 axle tube. Once you get it squared to the front crossmember you'd tack it to the jig and make a witness mark to the rear end so the rear goes back in it at the same place. The next are a couple fixtures for transpan or engine block. The last fixture is the front crossmember for Model Aish front crossmember, theres a stud sticking up just like the spring pack would have. This one is for a suicide front end, I have another that includes the front spindle mounts for stock type front end. This is one of the front end jigs, this particular one for M2 front, those 2 threaded pads are for the crossmember, the locating devices for the spindle/axle is the same, I couldn't get to a Model A jig, stuff in the way and I hurt my right leg yesterday carrying complete Hemi heads, with rockers and exhaust manifolds, 100yds and down a flight of stairs and another 100yds to my truck. I wouldn't recommend doing it, you could hurt your right leg. Dumb shit we do. Anyway, the spindle upright is adjustable and slides on the bar, you have an upright at each end, a pair of spindles and the axle captured between them at set at the height for the tire, hard to see but the note says 25" tire. The uprights hold the spindle level, you have to know that you are allowing for caster when you tack these in place, I clamp them until I can work from a secure crossmember and reverse engineer to where they should be from it and then tack. The 2nd fixture is the crank to pinion alignment jig, this one is for a Ford 9", I have adapters that bolt to this and then to banjo rear or a 12 bolt. I riveted the ruler to it with good intentions but now it is more a referance than a definative item, it is square to the centerline and you can slide a T square along it with confidance, you'll need to know the offset from the axle centerline to the start of the ruler, if you had dedicated fixtures for every rear then you could set the ruler proper. Another pic of the same fixtures so you can see the full size of them, the 2nd spindle upright is leaning on the box tube - its a real old one, you see those holes down low? they were from back in the days when dragsters ran those little aviation front tires, the 2 bolts on the bottom secure it to the box tube, there is a plate inside so the bolts don't dig into the tube and by shimming the plate you get the upright plumb. Hope this was helpful.
We used a frame bench bought from a school that shut down for a chassis jig. There is no way to build one that stout for what it was picked up for. And had wheels that made it mobile. Like one of these
Thank you. I am looking at different ideas, as I am getting ready to build a 32 ford frame for a 30 coupe. I was given what is left of my late father in laws I-beam jig that he used to build rear engine dragsters on. It is a single I-beam on rotating stands with all the cross beams & mounting points cut off. I have shortened it to 15' & have some ideas on how I am placing the cross beams to hold the 32 frame rails. I bolted a adjustable stiff leg in the center to help keep it from flexing. It is very simple, but should be enough to build the one or two frames that it might see. Bill
I got a half dozen 8' long barrel rack crossrails from work 20 years ago... cut 1 up as crossrails, welded them between [2] 8'ers, then a few angled braces to keep it square... then I welded 90* elbows from a buddy's collapsed canvas garage as skids along the bottom... also took [4] of his larger straight pipes 4" long and welded them to the corners as legs... cut [4] 15" long offset ends of the pipes [lets them slide into each other]… I slide the 15" sections up into the slightly larger 4" legs... makes the table about 24" off the floor … a 3/4" x 4' x 8' sheet of composite or outdoor plywood, cut it in half, then cut one half to just a little longer than the cowl, the piece I cut out lets me stand or sit inside the table if I need to... I then cut tapered sides on that cowl piece a couple inches wider than the cowl [lets me clamp things down].... drilled small holes and dropped nails through the composite and into the table to keep them in place if you remove the center "leaf"... I drill 3/8" holes through the composite and drop a couple 3/8" bolts through the cowl. subrails and mounting blocks in the holes... same with the B pillar mounting holes... trace the outer edge of the cowl and subframe onto the composite with a sharpie... after I remove the composite panels the 90* sections that were welded underneath work as skids / skis when the legs are removed... lets me drag it outside with the body still on the table … . only problem is every body buyer wants to keep the table / skid … note the "not 4 sale" on the front spreader . a '30 Coupester from 2015..
I built a jig for my project and just started laying everything out. I have the fixture level and set the frame at ride height. Working off a centerline. Lots of measuring.
Very nice. How do I determine ride height? I know what size tires I'm going to use but not sure about springs and just how to calculate ride height.
Since space is always at a premium in most home shops, my recommendation is to consider buying some welding tables at an industrial auction. I have two of them that are constructed the same so height and width are very similar. They are 4'x8' which gives me 16' total. The flat surface works well for a jig as you can bolt things to it by drilling and taping a hole where you need one, or simply tack weld a stop or brace and remove it later. If you plan on building multiple similar frames, you can make jigs like OJ did and bolt them in place when needed. Store them under the table when not needed. If you want the table to be wider, you can make bolt on wings for your wheels to sit on, or just put some 3/4" plywood on the table going crossways. Lots of ways to make it work and you have that nice flat surface to measure from with your metal scale(ruler) or better yet, a height gage. When done, you don't have to worry about storing it or having it in your way, cause its your main work surface for all other projects. The tables usually have adjustable leg screws so leveling them isn't a problem, and they are already flat. I have an overhead crane I built and it works great for moving heavy frames with suspension mounted. Remember, once you get all the stuff welded and bolted in place, you have to be able to get it off the jig. I put a bar across the top of the crane beams and hung a plumbob from it to set the centerline. I can tie it up out of the way and then drop it down again later if I need to verify what I'm doing. I think a dedicated frame jig is good when someone has a business doing multiple frame builds, but I think a big flat table works better for homebuilders.
Thats where calculating gets you in the neighborhood but actually tacking things together lets you see where you need to make adjustments. Spring mounting brackets from different manufacturers will give different results. Some brackets are designed to lower the vehicle some when installed. I would talk to some builders at rod runs that have a similar vehicle and measure how far it sits off the ground. Then sit your frame that high off the jig/table at the correct height and temporarily install your springs and wheels. Then you can see where the mounts for the springs need to be. It won't be perfect because you don't have the weight of the body on it yet. Tack the spring mounts in place so the frame becomes one unit, and then sit the body and motor/trans in place and see how much the ground dimension changes. Then if you need to, make changes to your spring mounts, you can do it and be pretty close.
I built my own jig for a 32 frame, which turned out to be an AV8 frame, but made the crossbars not only removable, but they can also be flipped over and used for other frames. It’s on large caster wheels, with four adjusting screws each corner for leveling before setup. Set up frame level, It worked very well. I also used it for pinching the frame to fit the model A body, this is the before pinch picture. After pinching; Sent from my iPhone using The H.A.M.B. mobile app
Its a little easier than you think if you use common sense. You know your tire size, so the front and rear axles are 1/2 of the tire size, you know the rear so then you'll know where the pinion height, then figure how much clearance you need under the oil pan, add the height of the oil pan to find the crank center (on most engines, not all) and that'll tell you how high the crankbolt is off the ground (ie, if you're using a SBC the oil pan is about 7 1/2" and you want 4" clearance then that puts the crankbolt at 11 1/2" off the ground, typically the top of the frame rail and crankbolt are same height) and exactly where its located in relation to the chassis jig. Those are your 'knowns', the driveline height, the chassis is the adjustable part by the use of springs. Its a simple logic problem, solve the 'knowns' and the unknown will solve themselves. Once you decide on the 'knowns' best not change them, screws the pooch. Everything will fall into place once you get it in your head about where the driveline and crankbolt is located.
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