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Projects Spring perch question

Discussion in 'The Hokey Ass Message Board' started by baspinall, Oct 22, 2013.

  1. baspinall
    Joined: Dec 8, 2009
    Posts: 440

    baspinall
    Member
    from SE PA

    This may be a thread somewhere in here but I can't find it. I'm building a 29 coupe and had my front end setup with Model A split bones. Don't like them as they are to small. Bought some mid 30's bones that are a lot more beefier but now my spring perch's are to short to clear the axle and get the nuts on. Do you guys mill the bones or just buy longer perch's? To me you would get longer perch's so to keep the thickness of the bones. I don't see longer ones at Pete and Jakes and such.
     
  2. 117harv
    Joined: Nov 12, 2009
    Posts: 6,588

    117harv
    Member

    If you have a buddy with a bit that has the same taper as the perch bolt, re-taper the end after grinding it down, that may be the best option $$$ wise. They do sell longer bolts, so that is an option too.
     
  3. Crusty Nut
    Joined: Aug 3, 2005
    Posts: 1,834

    Crusty Nut
    Member

    are you talking like 36-40 ish spring in front bones? They are really thick at the perch. You will need to mill the perch area thinner or buy some new, longer perches. Most aftermarket perches are long enough to accommodate a thinner bone and a lower shock mount.
     
  4. baspinall
    Joined: Dec 8, 2009
    Posts: 440

    baspinall
    Member
    from SE PA

    Yeah they are 36-40's. Just got off the phone with Pete & Jakes. They advised me to mill down the top rung on the bones and use a half thick nylon jam nut.
     
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  5. DICK SPADARO
    Joined: Jun 6, 2005
    Posts: 1,887

    DICK SPADARO
    Member Emeritus

    Well the mill down advise was correct but you still have to retaper the upper boss to match the perch taper. If you are using perch pin mount lower shock mounts you can get away with a half nut but if you are not you will have to add a taper washer to the lower radius rod fork so that the nut has a flat spot to tighten against or the perch will loosen up.
     
  6. baspinall
    Joined: Dec 8, 2009
    Posts: 440

    baspinall
    Member
    from SE PA

    I'm going to use the lower shock mounts. I asked the Pete & Jakes guy about retapering the top and he told me I wouldn't have to? Shouldn't the bottom of the taper that isn't milled down stay true to the bottom of the spring perch? Or are you saying that the 36-40 boss's are a different angle than the perch's sold?
     
  7. F&J
    Joined: Apr 5, 2007
    Posts: 13,196

    F&J
    ALLIANCE MEMBER

    Yes you need tapered holes on both the top and bottoms of the bone yoke. The perch won't stay tight without those.

    Your newer bones; the 35/36 are 2" between the yoke, and 37 up is like a Model A at 2.25".


    To trim the fat upper half of the yoke, you can cut with a band saw or hack saw, or whatever. Take about 1/2" off to end up with the same as the bottom piece.

    To retaper; you could buy a correct $$ reamer, but if you find an old drill bit around 1-1/8 or 1-1/4, you could resharpen it to the correct angle. I found an old 1/2" shank, short 1-1/4" bit, in case I do another set. You'd need to chuck the bone in a good drillpress vice and go wicked slow to get a smooth cut. To fast, too loose, will give a triangular hole:rolleyes:

    I did mine with the super fat, shorty Unibit. That bit did almost all the major shaping, then I made a welded flat bit, almost like a spade bit for wood, to do the final dressing.

    I choose to avoid those lower shock mounts; I see many cars at shows that did loosen up. Old school is drill a hole in the axle or weld a shock stud on the bottom of the axle.

    One car I just did; I flipped those 36 bones upsidedown and welded a shock stud to the fat stump where the spring-ahead perch was cut off. Yes, the caster will require piecutting the bone, but before flipping, the caster was too much at 10. So, I would have had to cut either way
     
  8. baspinall
    Joined: Dec 8, 2009
    Posts: 440

    baspinall
    Member
    from SE PA

    Great info there guys. F&J - How did you resharpen a bit on that angle? Certain tool for that? I have resharpened bits on a wheel but never tried for an exact degree angle. Guess I could make some kind of jig. As for the bottom shock mounts. I'm not 100 percent sold on using these I kinda like the axle mount look a little better anyway.
     
  9. DICK SPADARO
    Joined: Jun 6, 2005
    Posts: 1,887

    DICK SPADARO
    Member Emeritus

    BAspinall, If you choose to use the stock bones with 32-34 perch pins it is necesary to remove some material from the top portion of the yoke as it is to tall for the perch pin if left stock height, when you trim this down you remove most of the top portion taper seat, thus its necessary to recut the taper so the perch will seat correctly. In regard to the lower shock mount you must make sure that you have enough material removed from the top that the perch pin will protrude thru the shock mount at a depth far enough to get a nut to securly tighten up, a fiberlock half nut will work but all the threads must go thru the nut. The tapers of the shock mount should match the taper of the lower yoke fork so a mere dress up is all that is needed.

    F-J The reason that the lower mount have a tendency to turn is due to alignment of the shock absorber. If the upper and lower pivot points are not aligned in the same axis the lower shock mount with begin to turn to find the point of least resistance as the shock operates. If the lower shock mount has turned excessively the bracketry was installed incorrectly.
     
  10. 340HilbornDuster
    Joined: Nov 14, 2011
    Posts: 1,797

    340HilbornDuster
    ALLIANCE MEMBER

    Who sells the taper washers for the lower radius rods...?

    Looked everywhere..almost.

    Mahalo
    Tommy
     
  11. mechanic58
    Joined: Mar 21, 2010
    Posts: 681

    mechanic58
    Member

    Man I wish I was back in Hawaii. I lived on Kauai for almost 5 years.
     
  12. 117harv
    Joined: Nov 12, 2009
    Posts: 6,588

    117harv
    Member

    What is the degree of the taper for the wishbone yoke/bolt?
     
  13. David Chandler
    Joined: Jan 27, 2007
    Posts: 1,098

    David Chandler
    Member

    I used Speedway's perches with later 40's dog legged bones, on a stock A axle. They were long enough.
     
  14. Yes they are long enough in the threaded area but not in the shank part. They are all made to fit the original spring over axle and NOT for the use of the spring in front bones.
    On my RPU i was faced with this issue and the fix was to turn down two 5/8 unf nuts and loctite them on tight. The shank needs to engage the axle fully or damn near to it as there is an enormous amount of twist when braking so the perch bolt needs all the purchase it can get.
    This pic shows the nut in place and also shows just just how short the shanks are. JW
    [​IMG]
     
    irishsteve likes this.
  15. 117harv
    Joined: Nov 12, 2009
    Posts: 6,588

    117harv
    Member

    Anyone have the answer to my question?
     
  16. irishsteve
    Joined: Jan 10, 2017
    Posts: 412

    irishsteve

     
  17. irishsteve
    Joined: Jan 10, 2017
    Posts: 412

    irishsteve

    Great Idea on turning down the 5/8 nut to take up the space that's unsupported.
     
    26 T Ford RPU likes this.
  18. irishsteve
    Joined: Jan 10, 2017
    Posts: 412

    irishsteve

    Check with Pete and Jakes.They call them cone washers.Were used on 35-40 front ends originally.
     
  19. Thanks. :)
    I think they are 45* (or 90 depending how you look at it) but will check for sure and report back. JW
     
    Stogy likes this.
  20. Fordors
    Joined: Sep 22, 2016
    Posts: 2,165

    Fordors
    Member

    It looks to me that the included angle is 58*, or 29* per side.
    As a side note, 60* countersinks are common, but on a perch I checked it sure looks like 29* on a side to me.
     
    Stogy and 117harv like this.
  21. That is the case with a lot of Imperial countersink bolts. JW
     
  22. Checked one of mine and couldn't find my angle thingie. Does look like 58-60*. Will check it at work and report back. I don't like those cone washers for the bottom much as there is still a small amount movement on the perch bolt. Machining a partial taper on the nut works better. JW
     
  23. OK, checked the angles at work on our flash gear and it is 60*. I set it at 58* and rechecked and it wasn't correct. So its 60*. JW
     
    Stogy likes this.
  24. When you take a bit of time and effort to answer a question and help someone get the info they want and they don't come back and acknowledge you for your time or effort, i think is rude!! Why did i bother! JW
     
    Stogy likes this.

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