Join Date: Apr 2008
Location: Melbourne, Florida
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Polson, Not sure what bracket you're replacing but after looking at the link you provided, looks like maybe a spreader bracket. (8 holes) I would think that the type of loads the bracket will experience would determine which fastener to use, ie compression - rivets would do...heavy sheer or shock loads, I'd favor taping the holes for SS machine screws. With a wall thickness of .090, I'd go with no less than 10-24 and would probably favor a 10-32. And of course use some type of sealer/lube to isolate the treads from the mast. On a mast I completely overhauled, I use some aircraft goop to isolate the fasteners, others can tell you better what is suitable.
I opted to use all machine screws (some I had to step up to the next size due to corrosion) because the halyards were internal along with the mast anchor light wiring (no conduit). 'Pop' rivets normally require a 'tail' of one and a half times their diameter in length on the inside of the mast to be structurally viable and if one doesn't punch out the steel shaft out of the center after the rivet's pulled, it leaves sharp edges to chafe your halyards and wiring. I used a hole grip guage (available in most places that sell pop rivets) to determine the total length of machine screw I'd need to keep the fastener intrusion to a minimum. If there's nothing in your mast...go with the rivets if the loads are not too heavy...much easier installation.