Chassis Alignment Frame

  1. Myles1970

    Myles1970 Member

    Messages:
    87
    Location:
    Monaghan, Ireland
    Hi...I'm thinking I need to build an alignment frame for my resto (https://www.mig-welding.co.uk/forum/threads/ae86-booter-project.101029/), but am not sure what material to use.... would I be best using small I-beam or 80x40mmx3mm box on it's end?
    It'll be just a basic rectangle with one or two cross members .... it's in the earliest stages of design :D

    Thanks
    Myles
     
  2. Dcal

    Dcal Forum Supporter

    Messages:
    2,004
    Location:
    Antrim Northern Ireland
    Weight for weight the box will be stronger but even a 100 x 50 UB is twice the weight of the box you have.
    If you can bolt it to something solid, like a concrete floor when you are trying to straighten something I'm sure the box can be made to work.

    It’s down to the unsupported length and force you are applying (or trying to resist) so if you reduce the unsupported length by bolting to something solid or by bracing you increase the capacity of the member.

    Sorry if I can’t be more helpful, the devil’s in the detail, but 80 x 40 x 3 is far heavier than anything in cars with space frames, which will be doing a lot more work.
    I'd give it a go, it will be far easier to fabricate than using beam.
     
    Myles1970 likes this.
  3. jsf55

    jsf55 Forum Supporter

    Messages:
    531
    Location:
    Sunny Swansea
    Myles1970 and stuvy like this.
  4. stuvy

    stuvy Member

    Way too light, 10mm was the smallest Iv used 16mm I beams is best
     
    8ob and Myles1970 like this.
  5. Ruffian Member

    Messages:
    2,357
    Location:
    Devon UK
    Similar build to this style was how we did ours.

    But then again you could just use 2 I beams to pick up the floor pans.
     
    • 37752661ebf9dca48ca5d032941f6616.jpg
    8ob, stuvy and Myles1970 like this.
  6. daedalusminos Member

    Messages:
    859
    Location:
    Norwich
    Really depends what the purpose of the jig is and how many mounting points you intend to have. I used 100 X 50 X 3mm for the body jig part of my GT6 rotisserie, but I still cross brace the body tub since there are only 4 mounting points.... IMG_20180426_173953.jpg
     
    8ob, stuvy, Myles1970 and 1 other person like this.
  7. 500e

    500e Always buy fire insurance a flood is hard to start

    Messages:
    4,584
    Location:
    SWest UK
    Most are built on I beams or seriously heavy box
     
    stuvy and Myles1970 like this.
  8. Myles1970

    Myles1970 Member

    Messages:
    87
    Location:
    Monaghan, Ireland
    No, that is helpful... I've used I-beam for my bench, and one of the lengths was bent slightly, laterally....and box would be easier to work with. Also my local suppliers cuts were far from straight....
     
  9. Myles1970

    Myles1970 Member

    Messages:
    87
    Location:
    Monaghan, Ireland
    Well, I've a chassis rail that's 5mm too high, but it appears it was welded on by a previous restorer, so it'll be a case of removing and reinstalling as opposed to applying force. So I guess the main reason is to keep the shell straight during rust repairs and stitch/seam welding.... If I could attach it to the rotisserie that'd be a bonus...
     
  10. Myles1970

    Myles1970 Member

    Messages:
    87
    Location:
    Monaghan, Ireland
    Nice work... How do you attach the car to the frame? Existing bolt holes?
     
  11. daedalusminos Member

    Messages:
    859
    Location:
    Norwich
    The GT6 has a separate chassis so the jig picks up on 4 of the original 8 mounting points. For a true monocoque the subframe or suspension mounting points would be good.... But you need to ensure they're structurally sound. Also make sure you have enough room to perform repairs and that the jig isn't going to get in the way.
    Here there's enough room to replace the floorpan from underneath...
    IMG_20180616_164443_1.jpg
     
    Mike B, Myles1970, 8ob and 1 other person like this.
  12. Dcal

    Dcal Forum Supporter

    Messages:
    2,004
    Location:
    Antrim Northern Ireland
    I made a 100 x 50 box section frame to put a fiat 500 on a rotisserie, it was bomb proof, however it was a very short car.
    I’ll see if I can find photos but it was a long time ago.
     
    Myles1970 likes this.
  13. stuvy

    stuvy Member

    Here’s a 5mtr long car on the rotisserie I can’t find a picture of the old jig but google ‘Celeste’ there’s nothing better
     
    • 4AE10458-FB51-40A2-8800-65B993576A58.jpeg
    Myles1970 and daedalusminos like this.
  14. frank horton

    frank horton V twins are great but 4"s rule.........

    Messages:
    1,844
    Location:
    Soon 2 B Crete
    Even 150x50x4mm box is a bit springy.....but back to bracing....
     
    Myles1970 and 8ob like this.
  15. malcolm

    malcolm & Clementine the Cat

    Messages:
    9,106
    Location:
    Bedford UK
    I used C section for mine. Really bad as it had no torsional stiffness so I had to keep checking it with spirit levels. Was OK if supported on the floor, but no good on a roticerie.

    If you need torsion stiffness then box would be best. For floor mounted C section was handy for bolting supports to the flanges.

    [​IMG]
     
    arther dailey, stuvy, 8ob and 2 others like this.
  16. hazzabo Member

    Messages:
    32
    Location:
    Wokingham, United Kingdom
    upload_2020-7-30_7-0-7.jpeg
    Celette bench for crash repairs.
     
  17. 8ob

    8ob Forum Supporter

    Messages:
    5,640
    Location:
    moscow on thames
    I had one of those, tried to sell it and no takers so it went in the iron :vsad:


    The problem I found making spits with box section is it almost needs a jig just to make them, without a bit of thought they can end up like a banana when welded up.

    Bob
     
    stuvy and Myles1970 like this.
  18. stuvy

    stuvy Member

    that breaks my heart to read that

    we had one where I worked years ago and it was brilliant but sooooooo big it was actually a pain to move plus all the extra parts for it taking up room
     
    Ruffian likes this.
  19. Myles1970

    Myles1970 Member

    Messages:
    87
    Location:
    Monaghan, Ireland

    That's one serious piece of kit.... Maybe a bit Ott for what I need tho...
     
  20. Myles1970

    Myles1970 Member

    Messages:
    87
    Location:
    Monaghan, Ireland
    Yes I had a good read of your article...
     
Advertisements