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How Strong Do I Really Need? Axle Splines

Discussion in 'Early CJ5 and CJ6 Tech' started by GeoffreyL, Jun 10, 2018.

  1. Jun 10, 2018
    GeoffreyL

    GeoffreyL Well-Known Member

    moorestown, nj
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    So I have a Dana 44 19 spline powerlock and a Dana 27 10 spline powerlock. I have two sets of kelly hubs (identical to cutlass) that I want to use on all four corners and make the rear full float. Only problem I'm seeing now that I'm actually looking at what I've gathered is that all the available full float kits have 27 splines on the drive flange and either 19 or 30 splines on the carrier. Would it be a bad idea to make my own shafts with 10 spline outer to keep the kelly hubs? This jeep only has a 4cyl f head but would have 33x12.5 tires and 5.38's.
     
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  2. Jun 10, 2018
    Rich M.

    Rich M. Shoe salesman 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Maryland
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    I think you'd b OK. However if any other HP numbers are in your future, the 10 spline outer will be suspect.
     
  3. Jun 10, 2018
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    It's been done, Dr. Vern over on the Willys tech group did this using a drill press & a Corn Flakes box but he had to start with longer truck/waggy shafts & cut them down.

    upload_2018-6-10_19-6-20.png
    upload_2018-6-10_19-9-48.png
     
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  4. Jun 10, 2018
    Keys5a

    Keys5a Sponsor

    Florida Keys
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    Though I haven't done this yet, I have some front axles front the front of late-model Wrangers with 27 splines. I will cut off the yoke, and send them out to Moser (or similar) to have the splines cut to fit the 19 spline diff of our D44 rear axles. The axles are barely long enough and have enough diameter where they get cut. I plan on using the solid drive flanges (27 spline) from the Commando front as these are plenty strong. If I choose to flat-tow, I will just disconnect the driveshaft from the pinion flange. Its not that I don't trust a lockout hub on the rear, I just don't trust them enough to depend on them. A drive flange is simple and effective.
    -Donny
     
    Last edited: Feb 25, 2023
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  5. Jun 10, 2018
    GeoffreyL

    GeoffreyL Well-Known Member

    moorestown, nj
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    I don't know that I'm crazy enough to try that, but if it can be done at home by someone else, I'll ask a friend with a machine shop I plow snow for, he owes me a favor.
     
  6. Jun 10, 2018
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    If you are going to make your own axles it can be done. Most axle folks won't do 10 spline. Personally I'd step up to 19 spline and have a stronger splined area on the shaft. I've seen far more 10 spline axles broken than 19
    i wouldn't. Resplining those axle shafts is going to cut through the surface heat treating weakening them. But it's your money and your parts so if it works for that's a good thing.
     
  7. Jun 10, 2018
    Daryl

    Daryl Sponsor

    Bonney Lake, WA
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    To shadow Nick's comment, I have seen a couple re-splines twist away because there was no hardness where they were cut. Dutchman axles are cheap for the quality you get.
     
  8. Jun 11, 2018
    GeoffreyL

    GeoffreyL Well-Known Member

    moorestown, nj
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    How is resplining to 10 spline any different to 27 in terms of the heat treat? Does moser do something different? If it's that big of a concern could I try and heat treat with oxy acetylene?
     
  9. Jun 11, 2018
    47v6

    47v6 junk wrecker! 2023 Sponsor 2022 Sponsor

    USA
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    I did my FF setup. I was going to cut the 10 splines to run with some old locking hubs and the guys here dissuaded me from doing so. To do it right you need a mill and a spacer to turn the shaft accurately.

    What I did was buy the axle shafts from a front D44 blazer long side. They are 30 spline inner, cut them to length and sent them to moser to cut 27 spines into them to replicate the outer D30 shafts and use all the same stuff for the D30. They do not heat treat, just cut the splines. All the people I asked told me that its not a big deal and hot rod guys do this all the time without issue. I have had no problems..

    Its not particularly expensive to have moser cut the splines. I think it was like 75 bucks each? It was much much less than buying the tooling to cut my own 10 splines.

    One thing, I sent the outer D30 shaft to moser along with the ones I wanted to have cut and said explicitly to replicate the outer splines exactly.. Well they cut them too long and I ended up having to cut a groove in them for a cir clip to keep the shaft from walking out into the locking hub.

    The 30 spline shafts open up all the possibilities of upgrades to Elocker and new power locks and all that stuff.

    build your own full float dana 44?
     
  10. Jun 11, 2018
    GeoffreyL

    GeoffreyL Well-Known Member

    moorestown, nj
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    I just thought about it so I wouldn't have to buy different hubs and I really like the Kelly's cause of the large knob they have vs a warn. Plus if I went 10 spline I could have them cut for free at the machine shop I know. I don't know if he could cut 27 splines or if you would need a special machine for that
     
  11. Jun 11, 2018
    GeoffreyL

    GeoffreyL Well-Known Member

    moorestown, nj
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    Wouldn't the clutches in the powerlock slip before the splines or shaft could be damaged? If the 10 splines are strong enough for the front how is it that different in the back?
     
  12. Jun 11, 2018
    oldtime

    oldtime oldtime

    St. Charles,...
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    Shock loading is the main enemy of weak axle shafts.
    Shock loading occurs whenever a spinning tire suddenly grips.

    You might consider to re-spline your Kelly hubs to fit the larger 27 spline outer shafts.
    I seriously doubt if the hubs are hardened .
    But you may need to fill weld, rebore then respline the hub bores to 27 spline.
     
    Last edited: Jun 11, 2018
  13. Jun 11, 2018
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    Under the right (Wrong?) circumstances even a puny F4 can snap a 10 spline axle. It's rare, but it happens. It has to do with the depth the splines are cut to- 19 aren't cut as deep as 10, 23 are even shallower meaning more meat on the shaft.

    And more teeth mean forces are spread out over more area. There's also some profile change between the 10 & 19 spline teeth- I believe 10's are straight cut whereas the 19's are an "involute" profile- this may be inherently stronger.

    That being said if all you really want are locking hubs for flat towing & there's no Ed Roth-ish engine upgrades planned in the immediate future I'd say go with the 10's- if you break an axle so what? You can still drive home :D
     
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