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My tech week contribution....modern axles in a banjo

Discussion in 'The Hokey Ass Message Board' started by Jethro, Sep 10, 2012.

  1. Jethro
    Joined: Mar 5, 2001
    Posts: 1,908

    Jethro
    ALLIANCE MEMBER

    I will preface this tech post by saying this is for guys with access to a lathe or can have someone do the machine work for you. I am not a professional machinist and this was my first attempt at doing this but it was straight forward and not especially complicated.
    I had a banjo rear apart and a box of 9 inch stuff lying around and I wondered how close the parts actually were. The cross pin on the nine and the banjo cross pin are the same diameter. The spiders will interchange and the pitch on the gears looks real close. The nine inch 28 spline side gears have the same number of teeth as the banjo axles. The nine inch gears are a larger diameter but look to have a close tooth pitch.

    So heres what I did. First I had to grind the edge of the side gears down so they would fit into the carrier. You can see the difference between the original and ground gear.
    [​IMG]
    [​IMG]

    I originally tried to cut the teeth down but they are SUPER HARD! my lathe bits would barely touch them and would shatter because of the interupted cut. I ended up just using an angle grinder with a 80 grit sanding disc flapwheel. I covered the ways of my lathe with a leather apron to keep the grit and sparks from damaging the ways.


    The next thing was to bore out the carrier and the ring gear. I started with the carrier as it is just a casting. I bored it with about 8 thou clearance so it would turn freely and allow adequate lubrication.
    [​IMG]
    [​IMG]

    The ring gear was next and I was worried about it being too hard like the side gears. It was actually not as hard in the center as the side gears were. The center of the ring gear machined pretty easy actually but I had to take light cuts and go real slow.
    [​IMG]
    [​IMG]

    You can see the difference in the original gear on the right and the bored out gear.
    The next step was facing both pieces to get the proper clearance for the gears to mesh properly. I took 5 thou cuts and test fitted each time till I got a smooth differential action. Too tight and the gears mesh choppy. They will still turn but you would get a rough engagement. I also took enough off both sides so I could fit the hardened thrust washers from the nine inch. The process of cutting and assembly and disassembly took the longest time but it was important to get the right fit for proper operation.
    Once I was happy with the fit it was time to deal with the tubes. I found that the passenger side axles on mid 70's full size Fords were 29-3/4 inches long and would be roughly the right length. I only found this out by chance as I had one lying around.
    I cut off the original axle end and machined the end to the right diameter for a big bearing style housing end.
    [​IMG]

    [​IMG]
    I made up a jig to hold the housing end in place for welding. It is a piece of 3/8" all thread or ready rod as we Canadians call it. I machined a disc with the same diameter of an axle bearing to fit inside the housing end and a bar on the other end . I put a nut on it and tightened it so it wouldnt move when it was welded. The housing and the housing ends were machined square so the shouldn't be any misalignment problems.
    [​IMG]
    [​IMG]
    I mocked everything up and it fits good and the differential works like it should
    I am in the process of making another quick change for this to go into. I would post about making the quick change too but it won't be finished before tech week is over.
     
    Last edited: Sep 10, 2012
    Hnstray, fiftyv8 and bct like this.
  2. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 6,250

    Ebbsspeed
    ALLIANCE MEMBER

    Nice work! It's really kind of surprising how much parts interchangeability there is in the hobby, if you just do a bit of modification.
     
  3. MrMike
    Joined: May 21, 2010
    Posts: 139

    MrMike
    ALLIANCE MEMBER

    Very nice work! don't be afraid to post that quick change if it looks as good as the axle work it will be a winner.
     
  4. Old Guy
    Joined: Mar 1, 2009
    Posts: 136

    Old Guy
    Member

    That is pretty much how I did it on my homemade quickchange.
    If I recall, I turned down the shoulders on the side gears so I wouldn't have to bore as much out of the carrier housing. I used 31 spline side gears and they worked fine. Over 1000 miles and no problems.
    What did you use for axles?
     

  5. Jethro
    Joined: Mar 5, 2001
    Posts: 1,908

    Jethro
    ALLIANCE MEMBER

    I had an axle that I had used to make my Model A a roller. It turned out to be the exact right length. The axle was from a 78 LTD with a 9 inch. The pass side axle is 29-3/4 long. I went to pick a part and got another one for the other side.
     
  6. Old Guy
    Joined: Mar 1, 2009
    Posts: 136

    Old Guy
    Member

    Lucked out on that one. I had to spend $300 for some cut to length axles.
     
  7. Is there any way to get a limited-slip(two wheel power instaed of single)?
     
  8. I like this. Please post up the home made quick change when its done.
     
  9. Homemade44
    Joined: Feb 7, 2007
    Posts: 555

    Homemade44
    Member

    This is a very useful tech article.
     
  10. 383 240z
    Joined: Oct 28, 2007
    Posts: 429

    383 240z
    Member

    Damn it, I just happen to have a 9" center section and a banjo rear I drug home that needs brakes. Keith
     
  11. Kato Kings
    Joined: Aug 22, 2006
    Posts: 707

    Kato Kings
    Member
    from Minnesota

    Cool thread. I would love to see how you turned the inside and the outside of the banjo axle housings. Any pics of that?
     
  12. Mr48chev
    Joined: Dec 28, 2007
    Posts: 33,861

    Mr48chev
    ALLIANCE MEMBER

    Slick and I just happen to have a banjo rear end with no hubs or brakes and the pieces of a nine inch rear end in my stash of stuff. And a long time buddy who can make anything to boot.
     
  13. Jethro
    Joined: Mar 5, 2001
    Posts: 1,908

    Jethro
    ALLIANCE MEMBER

    Sorry, no shots of that....I'm the photographer and it's hard to run the lathe and take pics at the same time.
     
  14. Jethro
    Joined: Mar 5, 2001
    Posts: 1,908

    Jethro
    ALLIANCE MEMBER

    I think Hot Rod Works has a small locker that fits inside the banjo carrier. I think I could make a 8 inch mini spool fit inside but haven't tried it......yet!
     
  15. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    falcongeorge
    Member
    from BC

    Man, you must have been saving these up! You should hold a little back for the next tech week! Good stuff.
     
  16. great work....thanks for the post....
     
  17. 1950heavymetal
    Joined: Sep 9, 2008
    Posts: 323

    1950heavymetal
    Member

    Now thats cool! Great job.
     
  18. fordcragar
    Joined: Dec 28, 2005
    Posts: 3,198

    fordcragar
    Member
    from Yakima WA.

    Nice tech article. I think that Hot Rod Works used to sell the side gears, that were modified for this conversion.
     
  19. moefuzz
    Joined: Jul 16, 2005
    Posts: 4,950

    moefuzz
    Member

    Great Tech!


    .
     

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