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Technical Springs outside of frame help please.

Discussion in 'Traditional Hot Rods' started by 282doorUK, Jan 28, 2020.

  1. 282doorUK
    Joined: Mar 6, 2015
    Posts: 121

    282doorUK

    Hi folks, I've been diligently searching for more info on mounting front springs outside of a narrowed Chevy frame.

    I don't trust the original sized pins in a single shear situation, I have the shackle end of the springs sorted with a thicker pins, there are plenty of pictures of the finished thing, I but can't find any pictures of how to do the fixed end of the front spring to be stouter with a larger pin.

    Right now I have it held with a length of threaded rod and some tube spacers.

    I would be mighty gratefully for any help with this.

    CE8B8B18-7DB4-4344-B3C5-B1BE02DDB797.jpeg

    Shackle top pin bush was removed and a bigger pin the same od was pressed into the bracket, there is a thin bush in the tube welded to modded shackle so it's much stronger

    CC36FC23-2077-485D-806D-40367D097C70.jpeg

    Thanks.
     
    fur biscuit likes this.
  2. alchemy
    Joined: Sep 27, 2002
    Posts: 17,283

    alchemy
    ALLIANCE MEMBER

    Use a very thin bushing inside the spring eye. Use a larger rod all the way through. Tap the ends for threads. You could dress it up with a chrome spacer tube over the rod in between the frame horns.
     
    pitman likes this.
  3. 282doorUK
    Joined: Mar 6, 2015
    Posts: 121

    282doorUK

    Thanks, I did think of that, but it would leave the rod loose to move/rotate in the frame, which could lead to rattling and such,
     
  4. I'm a fan of suspension in double shear. I'm wondering about building a gussetted bracket coming down from the outside of the frame to pick up the outside of the shackle and ridgid spring mounts.
     

  5. 282doorUK
    Joined: Mar 6, 2015
    Posts: 121

    282doorUK

    Thanks for your thoughts, I agree, don't like single shear, but it was very common on pre-war racers which is what I'm sort of re-creating here, I think maybe them being so much lighter than when a normal body was on the donor chassis is the reason it worked.

    Making a such a bracket for the rear springs is easy and I'll be doing that, and it'll look ok, but purely for the look of the thing I would rather not go with them on the front.
     
  6. oj
    Joined: Jul 27, 2008
    Posts: 6,270

    oj
    Member

    Can you angle the spring so that it would go inside the frame at the front and do a doubleshear at the rear where it would kinda blend in?
     
  7. alchemy
    Joined: Sep 27, 2002
    Posts: 17,283

    alchemy
    ALLIANCE MEMBER

    Kinda goes against the "look" of the early racers if you put the springs under the frame. I think UK is right that the real racers were so light that the single shear didn't show as a problem.
     
  8. alchemy
    Joined: Sep 27, 2002
    Posts: 17,283

    alchemy
    ALLIANCE MEMBER

  9. THE FRENCHTOWN FLYER
    Joined: Jun 6, 2007
    Posts: 3,808

    THE FRENCHTOWN FLYER
    Member
    from FRENCHTOWN

    Boy, there are some really sweet looking cars pictured here.
     
    pitman and Just Gary like this.
  10. big john d
    Joined: Nov 24, 2011
    Posts: 255

    big john d
    Member
    from ma

    bushings for an open 4 wheel car trailer are usually 9/16 id 11/16 od they are not very expensive
     
  11. 282doorUK
    Joined: Mar 6, 2015
    Posts: 121

    282doorUK

    Thanks, I've seen all those pictures before and they do show the style. But this ^^ is the only one to give a hint of how the rod is held solid, tightening those nuts would squeeze the tubes and prevent any movement. I don't have a solid casting on the dumb irons like that one has, and to be picky the threads would be a stress riser in the worst place possible.

    Maybe I'm overthinking this, they were only low mileage racers and things could be a bit crude back then.
     
    Last edited: Mar 23, 2020
  12. 282doorUK
    Joined: Mar 6, 2015
    Posts: 121

    282doorUK

    Thanks I'll look into that.
     
  13. alchemy
    Joined: Sep 27, 2002
    Posts: 17,283

    alchemy
    ALLIANCE MEMBER

    That is Pete Eastwood's car. Hopefully he will see this thread and give us a closer look into how he built the spring mounts.
     
    282doorUK likes this.
  14. grumpy65
    Joined: Dec 19, 2017
    Posts: 925

    grumpy65

    @Pete Eastwood . Please see previous post.
    There you go @alchemy . That should alert Pete, just like it alerted you.
    Simply put @ in front of the username.

    I would also like to know this.
     
  15. rusty rocket
    Joined: Oct 30, 2011
    Posts: 4,349

    rusty rocket
    Member

    I think your over thinking all of this. You realize the roads back then were terrible and those frames seemed to make it thru all of that. With the roads we have now and the limited miles we put on a car I wouldn't worry about it.
     
    6sally6 and Asphalt Demon like this.
  16. 282doorUK
    Joined: Mar 6, 2015
    Posts: 121

    282doorUK

    I reckon you're right rr, especially on a car that will only ever see track days. :)

    Having said that, I have seen a few pics of heavier old racers where the single shear front pins have definitely bent up a bit, so the steel has gone beyond it's yield point, maybe had an off at some time.

    Thanks for all your input chaps, I'll just wing it somehow...
     
    pitman likes this.
  17. pitman
    Joined: May 14, 2006
    Posts: 5,110

    pitman

    Sometimes I've used split, or one-cut collars to locate a shaft, to avoid thread stress-risers. Best, to choose shaft matl w/care.
     
    282doorUK likes this.
  18. 282doorUK
    Joined: Mar 6, 2015
    Posts: 121

    282doorUK

    Got around the rear spring single shear, with a bit of bondo it might even look like a casting to a social distancing observer.

    67F0B77D-40DE-4271-90B6-2A55D686D04D_1_201_a.jpeg

    BF0255CB-7D79-4931-ABB2-B57F4A6D9B61_1_201_a.jpeg

    1C076A84-0BD8-4315-92D8-D485DBB7AA52.jpeg
     
    Weedburner 40, hfh, pitman and 24 others like this.
  19. That looks almost factory built. Well done!
     
    VANDENPLAS likes this.
  20. 282doorUK
    Joined: Mar 6, 2015
    Posts: 121

    282doorUK

    Thanks, almost is certainly good enough for me :D
     
  21. rusty rocket
    Joined: Oct 30, 2011
    Posts: 4,349

    rusty rocket
    Member

    Nice mount you built there. So what are we building here?
     
  22. Desmodromic
    Joined: Sep 25, 2010
    Posts: 571

    Desmodromic
    Member

    You have a legitimate concern about overstressing the spring's front single shear mounting trunnion.There are several ways to keep the moment on this minimized:
    • Fabricate a very stiff rear shackle, to ensure an even load distribution on the front and rear mounting components, to absorb lateral loads. Sides and top of shackle should be one piece (a weldment or machined from billet). Upper bolt should be in double shear, and a snug fit, with or without a metal (brass?) sleeve, with lubrication.
    • Spring should be have little to no arc, to minimize moments on the spring attachments as caused by lateral loads at the axle (i.e., when cornering).
    • With flat spring, front and rear spring eyes would be best be sleeved with compliant elastomeric bushes, not metal.
    • front cantilevered trunnion should be large as possible, and not threaded. Outer portion (beyond spring) could be reduced in diameter and threaded for nut and washer. Or outer half (only) could be drilled and tapped for bolt.
     
    pitman and 282doorUK like this.
  23. 282doorUK
    Joined: Mar 6, 2015
    Posts: 121

    282doorUK

    Thanks, 1928 Chevy beach racer type thing.

    04E30BC7-D9BA-42C6-84C5-462A1477F280.jpeg
     
    Last edited: Mar 23, 2020
  24. brading
    Joined: Sep 9, 2019
    Posts: 438

    brading
    Member

    282doorUk Must say that hanger looks real neat and strong. Easy mistaken for a original item.
     
  25. 282doorUK
    Joined: Mar 6, 2015
    Posts: 121

    282doorUK

    Thanks Brading, have we met on R&S ?
     
  26. brading
    Joined: Sep 9, 2019
    Posts: 438

    brading
    Member

    Ya we have met on R&S. I had a feeling that I had seen posts by you elsewere the 28 and Chevy got me thinking. Hope you have had no more of the problems you spoke about. Think you would get some interest if you posted pictures of your bracket in Tech Features in R&S
     
  27. 282doorUK
    Joined: Mar 6, 2015
    Posts: 121

    282doorUK

    No more problems so far Brading, good idea, I'll wait till I've finished and painted them and do a tech post then.
     
    cfmvw likes this.
  28. 282doorUK
    Joined: Mar 6, 2015
    Posts: 121

    282doorUK

    This heavy thing....

    FFECCB55-E401-4F7B-8446-6EF86B6DF7CD.jpeg

    Replaced by this heavier looking thing that actually feels lighter.

    I wasn't after getting them too perfect, needs to look more like a casting.

    3DCB1DCA-EBD3-4072-9FF2-7DA1A480FA6C_1_201_a.jpeg

    I'm expecting this next pic to draw some technical comments from you hawk eyed suspension guy's. So feel free to fire away :D

    62446195-9146-4049-B2CC-83C2B83FBB89_1_201_a.jpeg

    19D2351D-DD3B-4360-AD77-F122B0746AD6_1_201_a.jpeg
     
  29. 282doorUK
    Joined: Mar 6, 2015
    Posts: 121

    282doorUK

    Just got it rolling, no decision on the front, still with threaded rod holding the front springs on.

     
    wraymen, hfh, Just Gary and 10 others like this.
  30. Looks and sounds great!
     

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