Tech: Frame mods without a jig.

We all know it's very important that a car's frame be square and flat. A chassis table or jig would be ideal, but not all of us have the construction time, money and storage space to own one. Here's an idea I've found to work well: Fasten the frame to your concrete floor, in effect using the floor as a chassis table.

Put the frame on sturdy stands of some sort. Axle stands at ride height works, taller stands would make working underneath easier. Cut some small angle iron brackets- I used 2 x 2 x 3/16- drill a couple holes and fasten them to the floor directly under the frame with a concrete screw or two. Wrap a short piece of chain around the frame and join the chain and the floor bracket with a 5/16 or 3/8 turnbuckle. Put a lock nut on the right hand thread eyebolt. Level your frame by tacking shims between the stand and the frame, then crank the turnbuckles down tight to hold it in place. You can now cut, hammer, weld, etc. on the frame without it moving. I found I needed shorter stands, so I made a couple out of scraps of tube and plate with a 3/4" threaded rod in the top. The threaded rod makes adjustment easier.

An inexpensive laser level makes it easy to get the frame flat from front to rear, flat meaning not twisted. If you don't have a bubble level with graduations on it, fasten a tape measure to one edge, set up ther laser level, then stand the bubble level vertically on the top of the frame and read where the laser hits it. Corresponding locations on opposite sides of the frame should be at the same height if the frame's flat and level. Adjust the shims or screw jacks as necessary. To check for square, hang a plumb bob from the same locations on both sides of the frame and make crosshair marks on the floor. Measure diagonally between the marks up and down the frame. If your floor's not too smooth, duct tape a scrap of cardboard to the floor where you want marks.

 

Yeah, it'll work. My one buddy built the frame for his '56 Chevy pro street pickup on his garage floor and it's perfect. All Tig welded, tubbed, Mustang II style front. Of course, everything he does is perfect.

 

Sounds like it would work. I'm going to have to give that a shot.

 

Nice idea, thanks for sharing!

 

Great idea especially for newbies, most folks have the luxury or space for a table/jig.
Simple, logical and enough tech info to make it work out.
Well done.

 

Another thing that works well for that is tornado magnet (mobile home) leveling stands. Make sure they have lock nuts on the threaded risers. They will usually already have an "L" bracket on the top that can be tacked directly to the frame. Once they are tacked on you will have to spin the base on the floor for final adjustment. Lock the nuts down and everything is pretty sturdy.

 

I build my frame using 4 screw jacks. Get it leveled and pull square from corner to corner. It is kinda slow because you have to keep checking and weld slow but it is dead-nuts on

 

One of my old neighbors was a serious DIY rodder. He put threaded inserts in his garage floor then the adjusting levelers could screw directly into the floor. It worked very well for him.