Prop Shaft Adaptor: 19 spline to Keyed?

Discussion in 'Props' started by Swamplizard, Mar 13, 2024.

  1. Swamplizard
    Joined: Jan 2004
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    Location: Florida

    Swamplizard Senior Member

    Does an adaptor exist to mount traditional "keyed" props on a 19-spline 1.25 shaft?

    Google let me down so thinking "no"

    Anyone know better?
     
  2. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    The main problem is that a 1.25" spline shaft may have a hollow core of maybe 0.8". The keyed shaft would then have to have a diameter of no more than that. Even though you could make it, the shaft would shear.
     
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  3. seasquirt
    Joined: Dec 2015
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    Location: South Australia

    seasquirt Senior Member

    Is there scope for a short solid extension piece to be fitted to the splined shaft end, at the risk of possible balance issues to resolve. Made so the spline end of the adapter has a short solid section before the keyed end section, so they don't coincide creating hollow weakness.
    My rough backyarder solution: cut down and turn down an old prop to get the spline needed to mate the shaft. Weld some solid bar to the end, and turn it down (clocked up to the spline) to the diameter and length needed for the prop. Mill the keyway as standard to fit the prop. Scotch key the extension piece to the shaft's splined end in a likely permanent fashion. Drilling and tapping hardened spline and tough shaft may be difficult; weld would be permanent and could fail. Also added prop distance from skeg support is bad. Modifying or heating the shaft will weaken it anyway. My solution may work for an old put put boat, but not a modern powerhouse.
    Easier to get a new or S/H splined prop that fits.
     
  4. Swamplizard
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    Swamplizard Senior Member

    agree with the above - seems too light weight to handle HP
     
  5. gonzo
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    gonzo Senior Member

    I assume the shaft is on an outdrive or an outboard.
     
  6. C. Dog
    Joined: May 2022
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    C. Dog Senior Member

    What exactly are you doing Swampy? If we are aware of that then somebody may have a solution you haven't considered. Give us brand, model and photos if possible please?
     
  7. Swamplizard
    Joined: Jan 2004
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    Location: Florida

    Swamplizard Senior Member

    Vessel has Arneson ASD8 surface drives. Shafts are 19-spline 1.25 inch. The availability of props in the size range I need with 19-splines are few and far between so looking to see if I use keyed props.
     
  8. baeckmo
    Joined: Jun 2009
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    baeckmo Hydrodynamics

    Mercruiser Bravo 2 drives have 1 1/4" shaft and 19 splines IIRC. Not shure if it's the same spline type though, but worth checking, since you might find larger dia:s and smaller pitches available there, which is what you should look for.
     
  9. Swamplizard
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    Swamplizard Senior Member

    appreciate the suggestions.
     
  10. baeckmo
    Joined: Jun 2009
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    baeckmo Hydrodynamics

    ......and the splined metal hub in the "rubber hub" props can be turned to a conical hub with splines.
     
  11. Bryan carroll
    Joined: May 2024
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    Bryan carroll New Member

    I have 2 sets of 19 spline props depending what you are after
     

  12. Bryan carroll
    Joined: May 2024
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    Location: Canada

    Bryan carroll New Member

    What size you looking for as I have a couple sets
     
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