Stripped Screw Holes in Wood
By John Dewey
In rebuilding Steinway grand piano action frames for other technicians,
I have changed at least 75 action rail dowels. Part of changing the
dowel involves removing anything that has been used to plug the screw
holes that sticks up into the brass hole.
I have seen many types of repairs and the one that is hardest to remove
is where a strip of thin buckskin has been glued into the hole and the
screw inserted while the glue was still wet. I have never seen one of
these leather fixes that has pulled out. I realize this is not an
"ethical" fix but I believe there is a place for "ethical" fixes and
a place for "quick and dirty" fixes. Spending hours on an old player
that is headed for the scrap pile in a few years is like putting Rolls
Royce hub caps on a Nash Rambler.
I feel that it is very important to always put the screws back in the
holes they came out of and to turn the screw backwards until you feel
the thread fall into the old grove. I checked a set of new Steinway
flange screws. Putting the smallest screw in the largest screw hole
would result in a loss of 9.5 percent in thread contact area. Also,
every time you put in a different screw or put the original one in at
a different position it results in the screw thread cutting and bending
fresh wood. The oftener you do this the shorter the life span of the
hole will be.
John Dewey
East Central Illinois, USA
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(Message sent Mon 3 May 2004, 01:09:01 GMT, from time zone GMT-0500.) |
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