Register now to get rid of these ads!

Technical Twisted A

Discussion in 'Traditional Hot Rods' started by Willywash, Jan 19, 2020.

  1. Willywash
    Joined: Sep 18, 2019
    Posts: 37


    Using the original frame for my 31 A build. I welded in new front cross and kicked the rear up 5 inches using the rear cross sold in Speedway. The rails are straight and I built the frame on a level floor using weight and tie downs to keep frame from drawing during welding. The frame is also boxed. Long story short, I have fab skills and did the best job for what I had. I got a half inch twist from right front horn to back left corner. I can stand on one corner and someone can stand on the other and the frame goes flat and is level. There is no middle cross installed as of now. I'm thinking the weight of engine, trans and body will help level out the frame. I'm going to bring the frame to level when I install middle cross. Will the stress cause problems later on when car is on the road? It seems the front cross is where the stress will be, as it has to give to let the frame go flat. The rear is built much heavier.
  2. sloppy jalopies
    Joined: Jun 29, 2015
    Posts: 3,386

    sloppy jalopies

    A ship welder - straightener, or a tank builder [brewery], can show you what to do...
    heat here and spray water mist there... they know...
    I pulled both "inner and outer left '34 frame rail" 1/2" left to right with a torch and his soap stone marks... it bakes the carbon from the steel and makes it shrink...
    like he had said heat it red then go have lunch to let it cool... 1/2 hour later it had bent both left rails 1/2" to the right...
    gently tapped the front crossmember in, measured then tacked it...
    I had tack welded a "straight" 4' section of 3/4"x 3/4" tube to the flat bottom edge of the stock '34 tranny mount using angle measurements to triangulate it, for use as centered location points... thanks paul.
    pitman and flatford39 like this.
  3. -Brent-
    Joined: Nov 20, 2006
    Posts: 5,019


    My opinion, you gotta get that warp out.

    You'll be chasing it around a bit but the work will be worth it.
    Tim and mad mikey like this.
  4. know that's a 1/4 " out on 2 corners,..I doubt that'd be much of a problem when the car's all I wrong?
    Register now to get rid of these ads!

  5. lostone
    Joined: Oct 13, 2013
    Posts: 943

    from kansas

    Simple, put a 4 or 5 inch block on each of the 2 low corners. Have your buddy stand on one high corner and you on the other. Try bouncing on the high corners to see if it will easily twist over the blocks.

    It shouldn't take much to get 1/2 out.
  6. pitman
    Joined: May 14, 2006
    Posts: 4,746

    from Hampsha

    ^^^ I'm with them Maine-ahs,
    Heat, shrink, measure.
    Repeat, as needed.
  7. HotRod33
    Joined: Oct 5, 2008
    Posts: 2,274

    from MO

    You need to straighten it before you and cross members
  8. You must straighten it before going on. I had the same problem....frame twisted as a result of frame boxing. Took it to a body shop with a frame straightener and $75 later it was straight. Another guy did his at home in his shop by jacking it using a hydraulic jack. You jack it a little over center and then see how far it relaxes back. Cost = $0. If you don't do it now then every piece you add will reinforce the twist.
    clem likes this.
  9. Lloyd's paint & glass
    Joined: Nov 16, 2019
    Posts: 1,267

    Lloyd's paint & glass

    Is the frame boxed now? A stock frame is far from having any exact tolerance. If it's not boxed and you plan on doing it. I'd say cut the front crossmember loose, jig the frame, box it, and reinstall the front crossmember.
  10. redo32
    Joined: Jul 16, 2008
    Posts: 1,535


    1/4 inch on opposite corners is almost within Henry's tolerance. If the front and rear axles and the radius rod mounting points are square with each other it doesn't matter if the frame zig zags. You might need a couple more shims under the body. Your probably 1/8 inch corner to corner on the body. That ain't bad. Of course we all expect perfection, get it as close as you can and call it good.
    pitman and jimgoetz like this.
  11. clem
    Joined: Dec 20, 2006
    Posts: 2,602


    I would start again...........but that’s just me.........
  12. alchemy
    Joined: Sep 27, 2002
    Posts: 14,741


    My wife's Uncle laid the block foundation for his own house (he's not a homebuilder) and then cross measured and found it was a couple inches out. He knocked the whole thing down and started again. Absolutely nuts.

    But on a car frame I think I'd try to push/pull it into shape before going any further. Like said above, a couple blocks and heavy buds should work. A trip to a local frame machine would definitely work if you cant get it at home.
    Hollywood-East likes this.
  13. buick bill
    Joined: Dec 18, 2008
    Posts: 386

    buick bill
    from yreka;ca

    im sure when made they are perfect ! til you hit a pot hole with your 300 lb aunt in the rt rear !!
    anothercarguy likes this.
  14. sloppy jalopies
    Joined: Jun 29, 2015
    Posts: 3,386

    sloppy jalopies

    When cross measuring I try to get it closer than 1/8"...
    to henry they were cars, to us they are dreams and then treasure...
    I had the garage builders set a 4" section of 4" pipe with a 5/8" rod slid through a couple holes cut through it, the pipe pointed up into the concrete... taped off the top so no concrete gets in...
    when set tap the slab to find it [hollow sound] … knock out the "cover" …
    now you can hook a chain under the rod to straighten a bent axle...
    if you have that it and a jack can put some beef to a bent "anything" … HIH...
  15. Willywash
    Joined: Sep 18, 2019
    Posts: 37


    I decided to cut the sides on the front cross member, on the low side. Left the top of cross welded in. Applied weight across the front of frame with a beam and concrete blocks. Heated the top of cross red hot on low side. Let cool, then removed weight. It's within a sixteenth of level. Close enough. Then I reapplied weight and welded the cuts back on the sides of cross. Thanks for all of your help and interest.

Share This Page

Register now to get rid of these ads!


Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.