Hammer rake angle, etc.

[Keith Roberts]

This is a multi-part message in MIME format.

---------------------- multipart/mixed attachment
Try this. Take a hammer/shank/butt and with a pin, affix it through the
centerpin to a piece of paper. Scribe the arc made by the end of the shank,
Then drill a hole through the center of mass of the hammer and scribe that
arc. You can see that the center of mass is moving down at an angle to the
strings when the bore distance is set up at the center pin distance. If you
cut loose this missile (which is sort of what happens when let off occurs)
it would immediately begin to tumble. The attachment is the tangent lines of
the two different scenarios as the hammer hits the string. It appears to me
that the rebound would improve as the hammer flange moves closer to the
string. Rebound in an upright would play more of a role in getting the
hammer away from the strings than in a grand which has the acceleration of
gravity, 10 ft/sec/sec (not to be taken lightly), in it favor.
You are right Richard, the vector analysis you describe is true for an
infinitesimal point on the arc of the shank and it is assumed the mass is
centered on this point for all the force to be directed down the tangent
line of the shank arc.
Keith Roberts


----- Original Message -----
From: "Richard Brekne" > But I am not sure I will buy this. Lets see
here.... The shank assembly is
> pivoting on the centerpin, and regardless of where that is, when the shank
> itself is vertical then it has at that exact moment no vertical component.
If
> the hammer was glued at 90 degrees to the shank then the same would be
true for
> the crown of the hammer. So it seems to me that if the crown is to hit the
> string such there is no vertical component to its movement at the instant
of
> contact with the string then the shank would have to be vertical, the
hammer at
> 90 degrees to the shank. If in addition one wanted the crowns momentum to
be
> applied perpendicular to the string plane, then the string plane would
have to
> be parallel to the shank.


---------------------- multipart/mixed attachment
A non-text attachment was scrubbed...
Name: hammer.jpg
Type: image/jpeg
Size: 26995 bytes
Desc: not available
Url : https://www.moypiano.com/ptg/pianotech.php/attachments/54/5d/e3/b0/hammer.jpg

---------------------- multipart/mixed attachment--