Cordless screwdriver

[Dean May]

It's called a conical washer, sometimes a Belleville washer and its
properties lend itself much more nicely to the application. The split washer
is designed to keep the screw from turning. But the flanges come loose not
because of turning screws, but because of dimensional instability from
humidity. The conical washer keeps the joint tight even when there is
shrinkage.

http://www.machinedesign.com/BDE/FASTENING/bdefj4/bdefj4_9.html


Dean
Dean May             cell 812.239.3359
PianoRebuilders.com   812.235.5272
Terre Haute IN  47802

-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org]On Behalf
Of Keith McGavern
Sent: Sunday, November 07, 2004 8:07 AM
To: Pianotech
Subject: Re: Cordless screwdriver

At 8:36 AM -0400 11/7/04, John Ross wrote:
>Hi Bruce,
>I have seen split washers, on some older pianos. I just can't remember the
>brand name.
>So it has been tried, ....
>
>  > Has anybody considered a split washer as a torsioning device on
flanges.
>  > Bruce Browning-The Piano Tuner

Another type washer that has been used in flanges is one that is not
flat or split, but is warped in a fashion. Don't know it's technical
name.

Keith
--
Keith McGavern
Registered Piano Technician
Oklahoma Chapter 731
Piano Technicians Guild
USA

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