[Public-List] Lag bolts

[Robert Kirk]

   Each 3/8 lag screw, 2 inches into the wood, will take about a ton of
   pull-out apiece. Much more than you'd expect to need for a compression
   loaded mast step. Shear load should be relatively small but not zero.
   (I'm not sure how to interpret the bend John Boor reported in his 1/4 X
   6 bolts where they 'exited the bulkhead' since bulkheads are verticals.
   I assume bending stress but not shear. I found lots of bent bolts in
   Isobar along the hull-deck joint.

   On 10/28/13, Greg Bover<[1]gregbover at cbfisk.com> wrote:

   According to my tattered copy of Wood as an Engineering Material, the
   graph
   of the holding power of a lag screw in a hardwood like oak begins to
   level
   off once the length reaches seven times the root diameter, i.e., the
   diameter as measured between the threads. For a 5/16 bolt that is 7/32
   x 7
   or about an inch and a half.
   Greg Bover
   A-30 #114
   LINNET
   Gloucester
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