Re Scanning Electron Micros

[Kenneth Sloane]

                      Subject:                              Time:  11:26 AM
  OFFICE MEMO         Re Scanning Electron Microscope       Date:  2/15/95

                                   --   ORIGINAL POSTING   --

Subjects for SEM........How about music wire with the snickers: "the most
heinous example of string friction which rachets its way across the entrance
to the speaking length." Continue reading on p.30 of the PTJ 2/91, and find
out why I plead, "I'm hoping that the Guild can establish a National String
Friction Foundation to fund research for a cure to this tragic affliction."

Bill Ballard RPT      "May you work on interesting pianos."
NH Chapter, PTG               Ancient Chinese Proverb


                               --   MY REPLY   ---

I have found that the friction that causes the "ratcheting" is frequently
present -- at least in the agraffe section -- between the plate felt and
string behind the agraffe. In many pianos, the string exits the agraffe and
is angled rather abruptly onto this piece of felt. If the felt is rather
large and the total string contact to the felt considerable, much friction
can originate here. I have succeeded in eliminating the ratcheting Bill
mentions in pianos merely by lubricating this area (carefully, mind you, so
that none gets on the tuining pins) with McLube. When stringing, it is a wise
idea to replace this felt with the woven felt sold by suppliers that has some
synthetic fiber content. It seems to be a bit more slippery and though
horrible for flange and key bushing, very suitable as understring felt.
Another plus is that it is cheaper than the all wool woven felt.

Ken Sloane, Oberlin Conservatory