[pianotech] Upright hammer bore

[Floyd Gadd]

Hi Hank,

I found the thread where David Nereson gave a very helpful answer to my
question about upright action geometry.  Here's the link:

http://ptg.org/pipermail/pianotech.php/2009-May/009303.html

I trust this is helpful.

Floyd Gadd
Manitoba Chapter


Previously, Hank and Floyd wrote:

Hey everyone,
Does someone know how to determine what the hammer bore would be for an
upright? I usually try to copy the original bore but sometimes it not so
clear. What if an upright came into your shop without hammers and you were
asked to put hammers back on? Other than using sample hammers with different
bores and checking how it regulates up, is there a way to measure something?
Figuring out the bore on a grand piano is possible and easy to do and I do
it every time I hang a new set of hammers. What about uprights?
Hank

Hi,
I asked this question some time ago, and someone posted an excellent
reference to a published work that set this out in detail.  Now, for the
life of me, I can't seem to find it in the archives.  Can anyone provide a
refresher here?
Floyd Gadd
Manitoba Chapter