Re: reefing the 15

oldbandito@citlink.net
Sat, 19 Jun 1999 12:50:55 -0700


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West Wight Potter Website at URL
http://www.lesbois.com/wwpotter/
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>
> I recently asked for rules of thumb re: using screws in booms and masts on
> Brion Toss', Master Rigger, rigging forum and got the following info:
>
> If the wall thickness is less than 1/8" SS (stainless steel) rivets are
> preferred to drilled and tapped machine screws. There simply isn't enough
> wall thickness to hold the screw if it's any thinner. This is the minimum
> for a screw under shearing load; for a tensile load you'd need a much
> thicker wall.
>
> I have always been told that a sheet metal screw through a boom or mast
> doesn't have enough threads to hold in the long run. Typically, the threads
> on a sheet metal screw are coarser than on a machine screw. However, if
> you're going thru the boom/mast into another part (like a boom plug) then
> it's okay to use sheet metal screw, if they're properly bedded to prevent
> galvanic corrosion. Even still, drilled and tapped machine screws are
> preferred.
>

Damn . . . . I wish I'd have learned that THIRTY YEARS ago when I
started my rigging carreer (never had the balls to tack the word
'master' in front of the name). In those thirty years of
commissioning, rigging, re-rigging, building, etc, etc, etc, I have
NEVER had a self tapping screw pull out. Some of those boats
were balls-to-the wall racers, everyday sailors, and a couple made
serious blue water passages . . . . . never any failures. I guess
ignorance is bliss . . . . . .

Dik