Vertical hammer boring angle

[Ed Sutton]

Hi Terry,

You've got the clue in your question:

> the boring distance should be like on a grand -
> just
>> a hair longer than where the shank becomes parallel with the strings

This is usually true of grand actions, but in verticals, the hammer contacts
the string _before_ the shank becomes parallel to the string, therefore, in
order to strike the string at a perpendicular, the hammer must be a little
less than 90 degrees.
Take a look at your vertical action model.

Ed Sutton



> - ----- Original Message -----
> From: Farrell <mfarrel2@tampabay.rr.com>
> To: <pianotech@ptg.org>
> Sent: Monday, August 27, 2001 6:47 AM
> Subject: Hammer Boring Angle
>
>
>> Is there ever any good reason to bore a hammer on an upright such that the
>> long axis of the hammer & core and the shank form an angle less than 90
>> degrees? I'm putting new hammers and butts on an upright and don't want to
>> repeat original mfg. errors. I should think the hammer/shank angle should
> be
>> exactly 90 degrees and, just
>> to allow for a small amount of hammer wear. Original hammer core/shank
> angle
>> is about 88 degrees.
>>