Fh, Oval h, Rh, Pan h, Screws and Sleeves
In my opinion, pan head, or round head screws come to bear flat on the metal underneath the head,,,,, where as flat head and oval head need to come to bear in counter sunk holes.
There are round head machine screws in various places on my boom, and a few times I have had to use vice grips on the screw head to break it loose.
What ever the fastener, ( I think Brion, mentioned on this forum), corrosion will eventually effect it ! SS, Monel, Aluminum and Steel fasteners, included .
A nightmare of mine would be while on hardstand, the mast is lifted out with a crane, and the sleeved joint parts under shear loading on the fasteners, and someone on the ground gets hurt, or worse, you damage your boat with the falling lower mast section.
Mike, this is a dam good question of yours,,,,,,,
" 3. Is the purpose of the taper to gradate the stiffness as to allow the bending loads to dissapate? " ,,,,,, hope we get an equally good answer !
As you suspect, an untapered sleeve end , being a hard edge inside the mast, might just be where the mast could buckle and bend again .
On sectioned sleeved dinghy masts, I usually don't see a taper on the sleeve end, just a rounded edge .
Douglas
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