Tabernacle Bearing Material to replace aluminum?

Discussion in 'Materials' started by RyanN, Mar 16, 2008.

  1. RyanN
    Joined: Aug 2005
    Posts: 19
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    Location: North Carolina

    RyanN Junior Member

    The tabernacle pin on my aluminum mast consisted of a 1" stainless rod, threaded at both ends. On each end was a nut with a shoulder that fit into the stainless tabernacle base. The shoulder takes the load. Over this rod is an 5.5" aluminum tube with a 1" ID and a 1 3/8" OD that fits through the mast and serves to distribute the load. The aluminum tube is captive between the plates of the tabernacle base. The mast is sleeved at the bottom so the wall thickness is about 3/8" and the hole through the mast has a 1 3/8" ID.

    This worked well for 20+ years until it was time to remove the mast. The aluminum tube had fused to the stainless rod inside the mast, and no amount of persuasion could get it out. They may have even been held together with 5200. I finally had to cut the ends off of the rod.

    I would like to replace the aluminum tube with a high performance plastic. I need something with high compressive strength and some UV tolerance. The mast is lowered only rarely. I'd estimate that the mast weighs 600 lbs and is about 52' long to give you some idea of the loads. There are some wooden wedges between the mast and the base that serve to reduce the load on the pin. I hope to replace these with some sort of plastic as well.

    Anyone out there with a good knowledge of materials want to suggest a plastic and a source? Black Delrin comes to mind but there may be something better and I'm not sure Delrin is good enough. It should be machinable so I can get an exact fit.


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