[CAUT] Gram Tension Guages

[Don Mannino]

David,

You place the spring on the flange and use the spring to move the flange
(the bushing is 'rotating' on the pin).  Read the gram measurement while
flange is moving.  Try to move the part as smoothly as possible.

DM


-----Original Message-----
From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of
David Ilvedson
Sent: Thursday, May 18, 2006 8:31 PM
To: caut at ptg.org
Subject: Re: [CAUT] Gram Tension Guages


Don,

Explain "gram measurement should be of the flange while it is
rotating"...?

David Ilvedson, RPT
Pacifica, California



----- Original message ----------------------------------------
From: "Don Mannino" <DMannino at kawaius.com>
To: "College and University Technicians" <caut at ptg.org>
Received: 5/18/2006 4:33:12 PM
Subject: [CAUT]  Gram Tension Guages


>List,

>I prefer to use gram gauge specifications.

>I agree with Rick Baldassin, that using swings results in added 
>friction in the bass.  This affects the touch, which can affect the 
>weigh off and inertia (depending on how you do your weigh off). This 
>tapering of the friction is not recommended by any piano makers that I 
>know of.  The weight of the heavier bass hammers already assures 
>greater friction (from the knuckles) in the bass, and this added 
>friction works perfectly to maintain control of the heavier hammers.

>One can also try to taper the swings, but as Jim pointed out, this is 
>rather inexact, resulting in uneven friction.

>When repinning an action, I get my friction spec by doing a few test 
>flanges in the mid treble, where the tone of the piano reveals problems

>most quickly.  If the bushing cloth quality is sufficient to allow 2 
>grams friction on the hammer flanges in this part of the scale with 
>good solid tone, then this will be enough for the rest of the piano.  
>If the cloth is spongy, then a tighter fit will usually sound better.

>It is also good to adjust the fit according to the weather.  Pin 
>tighter by a couple of grams when it is humid.

>The gram measurement should be of the flange while it is rotating, not 
>the starting friction.  When pinning to a published gram specification 
>you should measure at the screw hole, but for consistency it is simpler
>to just measure at the end of the flange.   This takes a little
>practice, but is not too hard.

>Don Mannino RPT