Hammer bore dimension

[David Love]

I measure on the bench at each end also and assume that it's a straight
line.  I don't try and measure at each section.  Sometimes each end is a
different height in which case I might make a slight adjustment in the
bore.  You can calculate the bore from each end, or you can calculate
from one end and then adjust off the other end.  For example, use the
bass side center pin height to calculate the bore over all.  If the
treble side center is 1/16" lower, increase the bore at #88 by 1/16" and
graduate it incrementally as you go toward the bass.  A 1/16" difference
at the treble end will only mean a 1/32" difference in the center of the
piano so you can just estimate across the sections how it will affect
your initial bore dimensions.  It's usually not that much.  

David Love
davidlovepianos@comcast.net 

-----Original Message-----
From: pianotech-bounces@ptg.org [mailto:pianotech-bounces@ptg.org] On
Behalf Of Phillip Ford
Sent: Thursday, November 04, 2004 5:32 PM
To: pianotech@ptg.org
Subject: RE: Hammer bore dimension

>Measure the string heights, for example, at either end of the agraffe
>section, let's say hammer 21 requires 1 13/16" bore and hammer 53 (or
>whatever) requires a  1 7/8" bore.  Measure and mark the bore distance
>on the end hammers.  Now clamp them together in the same manner you
>would to gang file them.  Make sure that the strike point end for this
>group is in a straight line by butting it up against something solid.
>Now take a straight edge and using the bore markings on the end hammers
>(21 and 53) as a guide, strike a line  through the group of hammers
>which will give you point at which you will bore on each hammer.  Do
>that for each section, bass, tenor, 1st and 2nd
capo.....................
>
>
>David Love
>davidlovepianos@comcast.net

Thanks.  Also, how do you determine hammer center heights?  I measure
the 
centers on 1 and 88 (sometimes not the same height), with the action on
the
bench,  and assume a straight 
line between them (maybe not the best assumption on a Steinway).  Other 
suggestions?  Do you have a way of measuring center height for the same 
hammers on which you are measuring string height?

Phil Ford


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