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Removing mast head sheave axle pins

Discussion in 'The Cherubini Hunters' started by mjmercer19248, Dec 31, 2018. Add this thread to a FAQ

  1. mjmercer19248

    mjmercer19248

    Joined Jul 29, 2012
    77 posts, 0 likes
    hunter 37 cherubini
    US Apollo Beach
    1980 Hunter 37C with Kenyon 5280 mast. How the heck do you remove and replace the mast head sheave and axle pins?
     


  2. Ted

    Ted

    Joined Jan 26, 2005
    1,072 posts, 178 likes
    C&C 110
    US Bay Shore, Long Island, NY
    Post a photo so we know what it looks like.
     


  3. Ron20324

    Ron20324

    Joined Jan 22, 2008
    6,707 posts, 798 likes
    Beneteau 323
    US Annapolis MD
    One end of the pin probably has peaked splines to dig into the mast. Thus, you'd put in - or drive out- the pin from the opposite end. Can you see into the mast and I.D. which end has the splines? Maybe try one way, then the other, gently at first?

    Oh, yeah... don't drop it.
     


    DianaOfBurlington likes this.
  4. tmjb

    tmjb

    Joined Mar 13, 2012
    203 posts, 8 likes
    Hunter 36C
    US Glen Cove
    My ‘81 H36 has a Kenyon 5280 CR mast. The axle pins have integral stainless steel plates on one end (see left and right side of the photo below looking at the of the top of the mast). The plates are held in place with single machine screws. I haven’t tried removing these at the top of the mast yet (concerned about dropping things from aloft) but have at the base. The pins (at the base) pull out easily with the plate.
     


    DianaOfBurlington likes this.
  5. tmjb

    tmjb

    Joined Mar 13, 2012
    203 posts, 8 likes
    Hunter 36C
    US Glen Cove
    Not sure what happened to the photo. See below:
     

    Attached Files:



  6. DianaOfBurlington

    DianaOfBurlington

    Joined Jun 5, 2010
    979 posts, 49 likes
    Hunter 25
    US Burlington NJ
    They may well be corroded into place via bimetallic corrosion. Any time stainless and aluminum are together for a long time you can get this. Try heat.

    When you do manage to budge them, consider replacing them with solid SS pins with cotter pins both ends. While you're at it, push on a Delrin or nylon washer onto each end before fitting the cotter pin. The fittings you have were provided by Kenyon originally and represent rather old-school thinking. They're fine so long as they're in good condition; but remember all welds represent some minor level of metallurgic dissimilarity and after 40-odd years they may not be as reliable as when new. Remember that the sheave pins don't have to be tight in position, meaning side-to-side. They just have to not move up and down or fore and aft. If they were an extra 1/8" or even 1/4" between the cotter pins it would not be a catastrophe - actually might be better, allowing some little movement, to avoid the corrosion from being fixed in place.

    If you reuse what you have, follow the tried-and-true, industry-secret procedure of putting white electrical tape on the back of the plate where it will go flush against the spar, to metallurgically insulate the two metals. Trim it around the edges (not too close). You'll be surprised how well this works.

    Use a Delrin washer for the other side.

    No matter what you do, you're very likely to have to do some restorative surgery to the surrounding aluminum, which I expect will be well eaten by the stainless. Sand and file well - be sure to get rid of ALL traces from steel file or wire brush (DO NOT USE BRASS OR BRONZE!) - use epoxy with aluminum powder, and sand to your liking. And don't put it together again without a liberal coating of Tef-Gel on everything. Good luck!
     


    Last edited: Jan 23, 2019
  7. DianaOfBurlington

    DianaOfBurlington

    Joined Jun 5, 2010
    979 posts, 49 likes
    Hunter 25
    US Burlington NJ
    I'm well familiar with these pins and they don't have splines. Too expensive - no need for it at all. They are just solid 316 stainless rods with the plates welded on.

    You bring up a good point, Ron, about not losing anything into the mast. Even when the spar is lying down you can lose sheaves easily. One trick is to wrap a thin piece of line around the sheave, tie it tightly to itself, and dangle the tail of the line a safe distance away (tape it to the outside of the spar). Not having any line, use blue masking tape in the same way. I may be the only guy I know who has never lost a sheave down the spar - and that's including a lot of guys way more experienced at rigging work than I am (however that may be saying something). :dancing: