More on " Laminate Recrowning" .....

[Prof. Euphonious Thump]

..... which is what I've decided to "dub" this process
....

     ( And which, because I'm feeling particularly
generous today, I won't even try to patent or license
!!! )

A) Make  a Mylar (TM) or paper pattern of the bridge
sweep.
B) Feed it behind the posts, lined up with the
soundboard buttons, marking on it where the ribs
cross.
C) Trace it to a  plank. ( Like a 2x8 from the lumber
yard . )
D) Drill straight through the plank (3/8" holes ) on
the rib marks, and squeeze threaded inserts into them,
and run matching, long, 5/16" , full-thread bolts
through them and out the other side.
E) Place it all against the back posts, so the tip of
the bolts are right over the ribs, where they cross
the bridge line. 
F) Make your laminate out of whatever you feel
comfortable with, and place it along the top of the
rib spine. Place a  block-of-wood caul  on top of
that, and run the bolts out until they press the caul,
laminate, rib, rib spine togetrher, bowing out the
board.  Start with ribs toward the middle, and work
toward the ends of the bridge. 
 ( Toward the treble first, probably.
G) Check to see what sort of bearing you're getting.
H) When you have the bearing you want ( and probably a
 little more ) wrap tape around the bolts where they
go through the plank, to mark how far they're threaded
in, and back them out. Then put glue on the laminate,
and put it back under the block caul and squeeze
everything together again, to the point the bolt was
turned in, before. 
    Let dry, remove, and check your bearing again. If
it were OK to use some sort of close-grained wood
instead of sugar pine, thin laminates could be useds,
and added if the bearing were inadequate. 
I ) Check for load bearing, fix cracks, restring.

Peace,
 Thump






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