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Projects How to shorten my own drive shaft.

Discussion in 'Traditional Hot Rods' started by FROM91, Apr 1, 2014.

  1. FROM91
    Joined: Sep 19, 2010
    Posts: 506

    FROM91
    Member

    I'm running a 33-34 rear end on duce rails so I need a few inches gone. Looking for best home method or home jig I could make, or even recommendations on who to take it too here in southern California to have shorten. Where abouts of a late v8 32 drive shaft for sale, What ever I'm all ears.

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  2. bonzo-1
    Joined: Oct 13, 2010
    Posts: 342

    bonzo-1
    Member

    You can do it yourself with a lathe, but will probably need balancing anyways.
    I have done three and two of them needed to be balanced.
    Your best bet is to take it to a driveline shop and have it done.
     
  3. lanny haas
    Joined: Nov 1, 2008
    Posts: 560

    lanny haas
    Member
    from Phoenix AZ

    just my thoughts, but there must be a lot of places in Whittier, that can do this. But i have seen it done with 4X4 1/4 channel, that after you cut the shaft the channel will keep it stright as you weld it, but i dont think it would cost too much to have a shop that thats what they do, and ballance too. nothing worse than a wobbley drive shaft.
     
  4. birdman1
    Joined: Dec 6, 2012
    Posts: 1,631

    birdman1
    Member

    I grind the weld at the rear of the driveshaft ,where it is welded to the rear u-joint housing. take care not to gring into the housing any more than nesesary to cut the weld. there is a factory flange on the u-joint housing that you will fit the cut driveshaft onto and re weld it. If you take a square to check the cut off shaft, it will be straight. then fit the tubing onto the flange and weld it 180* apart, so it does not "pull" the shaft crooked. weld a little(1/2") at a time. i use 1/8" rod, 7018, and peen the hell out of it. install the shaft, then hold a pencil next to the shaft as you rotate it one turn. you will be able to see how straight you got it and if it is acceptable to you, go out and try to twist it off with a few good burnouts!!
     
  5. Mr48chev
    Joined: Dec 28, 2007
    Posts: 34,787

    Mr48chev
    ALLIANCE MEMBER

    The way JD Fikes of Waco taught me in the mid 70's was to cut through the tube right next to the weld on the weld flange that looks like this when you pull the tube off it.

    [​IMG]

    You just want to cut through the tube and not the flange all the way around next to the weld so you can take it apart.

    Then what he did was wrap something around the driveshaft tube where he wanted to cut it so he got a square cut on the tube (that is very important) once he had it cut he mated it with the end flange and after getting them squared up and the yokes in phase with each other he welded it back together.

    His trick was to use one of those band style ring compressors as a guide for the hacksaw cutting all the way around the shaft a little at a time. Saw and turn, saw and turn and do it again until he had a groove cut all the way around.

    I've done about ten of them over the past 35 years and had fair luck but have had at least one I did that was so far out of balance when I was done I had to junk it and start over. That is the big rub with doing it yourself. You have a 50/50 chance of it being balanced .and not vibrating when you are done
     
  6. rpu28
    Joined: Jan 17, 2006
    Posts: 197

    rpu28
    Member
    from Austin

    Are we talking about open or closed drive?
     
  7. edwardlloyd
    Joined: Aug 2, 2003
    Posts: 2,072

    edwardlloyd
    Member
    from Germany

    Closed, obviously.

    I take mine to a machine shop with a big lathe. Costs about $200 but that's for the tube and shaft. Most machine shops can do it. BTW, I find the later '41-'48 shafts easier to shorten and they're cheaper to buy. Easier because the tube has a constant diameter for most of it's length and because the shaft uses the removable coupler which can be removed, then the shaft gets shortened then turned down at the end and the coupler slides back over and then weld up. That way it stays nice and true. For a '33 axle you'll need to buy the spline adapter coupler available from V8 parts suppliers.
     
  8. AZbent
    Joined: Nov 26, 2011
    Posts: 280

    AZbent
    Member

    If you take the time to mark the drive line with a couple of marks, before any cutting, then your chances of having a fairly balanced drive line is increased dramatically(sp).
     
  9. JeffB2
    Joined: Dec 18, 2006
    Posts: 9,577

    JeffB2
    Member
    from Phoenix,AZ

    Guess we lucky here in Phoenix I had Dick's Driveshafts on McDowell do mine shortened balanced and new joint pressed in for $65 :D If you want to DIY it check this out: https://www.youtube.com/results?search_query=shortening+a+driveshaft+
     
  10. slowmotion
    Joined: Nov 21, 2011
    Posts: 3,359

    slowmotion
    Member

    ^^^ Yep. Index it and chances of a usable balance are better. Did this years ago going from a 3 gear Sag to a 4 gear Muncie in a '62 Impala. Needed to shorten the shaft 3" or so. Removed the yoke as described above, indexed, welded up, worked fine, no shimmy shimmy shake.:D
     
  11. fortynut
    Joined: Jul 16, 2008
    Posts: 1,038

    fortynut
    Member

    Search the HAMB for recent offerings for '32 shafts. Do a Google search for, '32 Ford driveshafts for sale (also try search all junk). An OEM part could easily be cheaper than having one shortened. Take the advice of edwardllyod who suggested using a '41-48 shaft. (ditto on HAMB & Web & search all junk search) The tube should be easy to shorten with a straight forward approach and angle iron, as all tubes are easy to align with a little finessing. I would suggest using ratchet clamps to get a straight cut as suggested by Mr48chev. aka radiator clamps they come in quite large sizes that are available at truck parts places. Good luck. Keep us posted on your progress. Carl
     
  12. rpu28
    Joined: Jan 17, 2006
    Posts: 197

    rpu28
    Member
    from Austin

    If it were obvious, I wouldn't have asked.

    Cut the torque tube as needed and use a machinists square and file to square the cut end. Bore the rear flange on the cut-off piece so it lightly press-fits over the diameter of the rear of the remaining torque tube. Remember to account for the thickness of the flange when cutting the torque tube to length. Press the flange on the tube and check for squareness; it should be flush with the rear of the tube if the tube was squared properly. Weld the flange onto the torque tube carefully, welding around the beveled inside lip instead of the outside diameter. Be sure to get the oil-return slot near the same orientation as the radius-rod mount (i.e. so the oil drains correctly).

    Cut the drive shaft such that the rear spline has a few inches of stub on it, and remove enough of the remaining shaft so it fits between the rear end and transmission correctly. Have your machine shop true the diameter of the end of the shaft and of the spline stub, and make a sleeve to couple them together. Let a good welder weld around the ends of the coupler and through a few rosettes, and then have your machine shop make sure the spline stub doesn't wobble. Don't run this drive shaft with a 500 HP crate engine.
     
  13. judgeyoung
    Joined: May 21, 2010
    Posts: 146

    judgeyoung
    Member

    I don't think most of the previous responses understand that this is a closed driveshaft. On my 28 roadster with V/8 rear, I had a guy shorten my shaft. He did it differently than I would have guessed, but it worked great and he guaranteed it would break elsewhere than his fix.

    He didn't want to respline the ends, so he made a cut and machined a threaded hole in one end and a matching threaded stud on the other with correct length mating surfaces. He had also machined a bevel into the outer mating surface for welding. When he finished mating and welding, he machined it true and I could not find where he joined it.

    Because of the small diameter, relatively short length, and the support bearing (can't remember for sure, the '33 may not have them...) balancing should not be too much of a problem.

    It seems like it would be relatively easy to produce custom length shafts new. Doing the housing is pretty easy if you are careful.
     
  14. fortynut
    Joined: Jul 16, 2008
    Posts: 1,038

    fortynut
    Member

    The image of the last fix suggests someone with master level machinist expertise. I would never have seen that solution in my imagination. Thanks judgeyoung for sharing that. I hope FROM91 realizes how cool doing it like that is. If all else fails and you find yourself falling through space, you can call Eric Vaughn in Monrovia. His experience in the area of machining parts for hot rods might be of use to you. At least, he was always helpful to me; though I've been gone from So-Cal over ten years, now. Things change, though. Just a suggestion. Carl
     
  15. FROM91
    Joined: Sep 19, 2010
    Posts: 506

    FROM91
    Member

    MUCH APPRECIATED feed back!!! thanks guys, just took me 30min to read it all...But any way, I called Power Train Industries in Anaheim, and the dude said bring it tell him how long I need it, 75 BUCKS!!! Pretty stoaked on that price!

    ONE more question does any body know the exact length of a late V8 1932 drive shaft ?
     
  16. dcadwell
    Joined: Mar 13, 2014
    Posts: 49

    dcadwell
    Member

    I had a ’37 rear end that came with a project car. I found a tubular drive shaft and used the 6 to 12 spline adapter method. The center bearing was removed from the torque tube. By turning the adapter to a press fit in the cut down driveshaft, straightness and strength is much better. The milled axial relief is to clear the weld flash on the inside of the driveshaft. You could just as easily grind down the weld flash. After the spline adapter is pressed in, it is welded to the driveshaft. The torque tube had been cut and butt-welded too short and out-of-square. I made a press-fit coupler with internal shoulders to replace the messed up weld and lengthen the tube about 1”. The press fit, shoulders and plug welds initially hold it square so you can weld around the circumference.

    I wanted to do the work myself but struggled a little figuring it out. I thought a couple pictures here might help someone facing a similar pile of parts.
     

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  17. wood470
    Joined: May 21, 2008
    Posts: 226

    wood470
    Member

    Just some asides not necessary for a closed shaft, a large pipe cutter works way better than trying to cut straight with a hack saw and make absolutly sure you keep the relationship between the two ends exactely the same as before you cut it
     
  18. v8juice
    Joined: Dec 28, 2013
    Posts: 280

    v8juice
    Member

    ^^^^
    I agree on the pipe cutter it naturally wants to cut straight
     
  19. Check out my 32 roadster build thread post # 52 to # 60 shows how I do mine, did it the same way with my 32 coupe, which now has over 4,000 miles on it with no problems. Drive shaft will need to go to machine shop to be re-splined.
    http://www.jalopyjournal.com/forum/showthread.php?t=812914
     
  20. edwardlloyd
    Joined: Aug 2, 2003
    Posts: 2,072

    edwardlloyd
    Member
    from Germany

    You might want to make it 1/2" to 3/4" longer than Stock. This centers the rear wheels in the wheelhouse better. You also have to move the rear crossmember back but that's not too difficult. You are starting with a longer shaft anyway do might as well.


    Twitter @edsrodshop
     
  21. Andy
    Joined: Nov 17, 2002
    Posts: 5,221

    Andy
    Member

    You can use a Model A shaft. You are going to cut the end off anyway so an A shaft would work just as well as a 32-34. I would make a sleeve and weld in a common 6 spline coupler. You can check for straightness by putting the shaft on the rear and turning the rear. See if the trans end wobbles.
     
  22. I used to cut the flange welds with a diamond hacksaw blade. Just keep rotating the 'shaft and keep the cut as straight as possible.

    I also used to borrow a big pipe cutter for the tube cut. I sanded the area where the rollers ride so I'd give the cutter back in good condition, it also ensures a square cut.

    Bob
     
  23. fortynut
    Joined: Jul 16, 2008
    Posts: 1,038

    fortynut
    Member

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