Piano hammer shaping tool

A hammer shaping tool is designed with two parts: a piano hammer template and a sanding strip. The template's face surface is a mirror of an desirably shaped piano hammer with side walls forming a channel along the face surface of the template. The width of the face surface, and consequently the channel, is generally the same as the width of the striking edge of the hammers. The sanding strip likewise has the same width as the striking edge of the hammers. The sanding strip is placed, cutting side against the hammer, on the striking edge of the hammer. The template is then placed against the low friction side of the sanding strip and a portion of the hammer. The sanding strip is pulled through the template channel, the low friction side of the sanding strip sliding against the face surface of the template, and the cutting surface of the sanding strip engaging the surface face of the piano hammer, cutting the hammer facing surface to the desired shape. The strip and guide can then be placed on another portion of the hammer and the process repeated, eventually shaping the entire hammer. The amount of pressure exerted on the tool against the hammer shoulders in conjunction with the sandpaper grit size dictates the amount of felt removed from the hammer.

BACKGROUND OF THE INVENTION 
1. Field of The Invention 
Applicant's invention relates to a hammer shaping tool; and, more 
particularly, to a tool that is designed to correctly shape and voice 
piano hammers. 
2. Background Information 
The modern pianoforte, or piano, was developed in the early 1700's when a 
harpsichord was modified to include an escapement action, which involved 
depressing a key thereby causing a hammer to strike a string. The piano 
was later refined to include repetition, or double-escapement, action 
which is now, in modified forms, employed in most pianos. Pianos are found 
in many forms, however, they are generally comprised of a frame, strings, 
a sound board, casing and wrest plank, and the action. The action consists 
of a system of levers whereby when a key is pushed, the hammers are 
actuated to strike the piano strings. The strike of the hammer against the 
string causes the string to vibrate and, consequently, produces sound. A 
piano's sound can be divided in two parts; loudness, which depends upon 
the amplitude of the vibration--determined by the power with which the 
hammer strikes the string--and the pitch, which depends upon the frequency 
of the vibration--determined by the diameter, length, and tautness of the 
string. In order for the piano to create pleasing sounds, the strings must 
be tuned such that harmonic vibrations and harmonic series are formed. 
To produce sounds that are in tune, clear and precise without fouling other 
strings, the hammers must be flat with sharp edges. In order to shape the 
piano hammers (also referred to as "voicing" or "dressing" the hammers), 
technicians must smooth out ridges and grooves that develop in the 
hammers. Ideally, the hammers should have square shoulders with flat even 
strike points (crown) and a symmetrical shape. 
Felt is commonly used to create the striking surface of the hammers. 
However, the hammers may vary in structure and materials used in their 
construction. The construction design of piano hammers is based upon 
initial cost, upkeep cost durability, and aesthetic characteristics (i.e. 
characteristics of the sound created upon operation). 
A common problem encountered during the use of conventional tools and 
methods to shape or voice the hammers, is that the hammer are incorrectly 
shaped. Technicians accidently shape the hammers at an angle, or leave a 
rounded or lipped edge on the hammer. Additionally, it is difficult for 
technicians to shape each hammer in a desired form, or in a form that is 
consistent from one hammer to the next. These problems are due, in part to 
variances in the way tools are held and applied to the hammers, as well as 
most of the work being done "free hand." The shape of the hammer affects 
the sound characteristics produced by the piano, therefore it is desirable 
to have consistent, ideally shaped piano hammers. Finally, even when the 
technician is able to correctly shape the hammer, it is a time intensive 
process. 
Thus, there is a need for a tool which a) correctly and accurately dresses 
piano hammers, b) dresses hammers in a consistent fashion, and c) reduces 
the amount of time needed to adequately dress the hammers. 
SUMMARY OF THE INVENTION 
The present invention is an apparatus and method for shaping piano hammers. 
In order to solve the difficulties presented in attempting to accurately 
shape piano hammers while at the same time reducing the time necessary to 
shape said hammers, a piano shaping tool has been developed using a 
template and flexible sanding strip. Another advantage resulting from this 
invention is that the hammers are consistently shaped from one hammer to 
the next Additionally, this apparatus is so easy to use that it reduces 
the time needed to shape the hammers, as well as reducing the technical 
expertise required to adequately shape hammers. 
The tool is designed with two parts: a piano hammer template and a sanding 
strip. The template is molded, machined, or otherwise shaped such that its 
face surface is a mirror of a desirably shaped piano hammer. On either 
side of the template are side walls which form a channel along the face 
surface of the template and which is used to hold both the sanding strip 
and the piano hammer in place. The width of the face surface, and 
consequently the channel, is generally the same as the width of the 
striking edge of the hammers. The sanding strip likewise has the same 
width as the striking edge of the hammers. 
In order to shape a piano hammer, the sanding strip is placed, cutting side 
against the hammer, on the striking edge of the hammer. The template is 
then placed against the low friction side of the sanding strip and a 
portion of the hammer. The technician then pulls the sanding through the 
template channel, the low friction side of the sanding strip sliding 
against the face surface of the template, and the cutting surface of the 
sanding strip engaging the surface face of the piano hammer, cutting the 
hammer facing surface to the desired shape. The sanding strip and template 
can then be placed on another portion of the hammer and the process 
repeated, eventually shaping the entire hammer. The amount of pressure 
exerted on the tool against the hammer shoulders in conjunction with the 
sandpaper grit size dictates the amount of felt removed from the hammer. 
It should be understood that the piano hammer shaping tool may vary based 
upon construction goals.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 illustrates a side elevation view of the present invention. The 
piano hammer template (10) is comprised of a rigid structure, shaped in 
such a manner that the face surface (12) of the template (10) mirrors a 
portion of a desirably shaped piano hammer facing surface (not shown), 
when viewed from the side or in profile. Generally, the face surface (12) 
will be smooth and relatively slick, in order that a sanding strip (50) 
more easily slide against the face surface (12). Attached to a first side 
(14) is a first side wall (16) which extends beyond the face surface (12) 
of the template (10), which in combination with a second side wall (20) 
(see FIG. 3.) forms a channel (24) along the face surface (12) of the 
template (10) in which the piano hammer to be shaped will fit and through 
which the sanding strip (50) will slide. 
FIG. 2 illustrates a front elevation view of the template (10). It further 
shows the attachment of the first side wall (16) to the first side (14) of 
the template (10). Likewise, attached to a second side (18) is a second 
side wall (20). A channel (24) is formed along the face surface (12). The 
first side wall (16) and the second side wall (20) generally will have the 
same shape. 
FIG. 3 illustrates a side and back perspective view of the template (10). 
It shows that generally, the back (22) of the template (10) is shaped to 
meet the contour of the users hand. This enables the user to more easily 
hold the template (10). The first side wall (16) and the second side wall 
(20) are attached to the template (10) so that no lip or groove is formed 
along the back (22) of the template (10). 
FIG. 4 illustrates a front elevation view of the flexible sanding strip 
(50). The flexible sanding strip has a first side (52) with a cutting 
surface, and a second side (54) with a low friction surface. The flexible 
sanding strip (50) is designed to be held by the template (10) against a 
piano hammer to be shaped. The flexible sanding strip (50) is held cutting 
surface (52) against the piano hammer, and low friction surface (54) 
against the face (12) of the template (10). In order to shape a piano 
hammer, the sanding strip (50) is placed, cutting surface (52) against the 
facing surface of the hammer. The template (10) is then urged against the 
low friction side (54) of the sanding strip (50) and a portion of the 
hammer. The technician pulls the sanding strip (50) through the template 
channel (24), the low friction side (54) of the sanding strip (50) sliding 
against the face surface (12) of the template (10), and the cutting 
surface (52) of the sanding strip (50) engaging the facing surface of the 
piano hammer, cutting the hammer facing surface to the desired shape. The 
sanding strip (50) and template (10) can then be placed on another portion 
of the hammer and the process repeated, eventually shaping the entire 
hammer. The amount of pressure exerted on the template (10) against the 
hammer in conjunction with the sandpaper grit size dictates the amount of 
felt removed from the hammer. 
Although the invention has been described with reference to specific 
embodiments, this description is not meant to be construed in a limited 
sense. For example, the shapes and sizes of the template may be altered to 
correctly shape various sized piano hammers. Various modifications of the 
disclosed embodiments, as well as alternative embodiments of the 
inventions will become apparent to persons skilled in the art upon the 
reference to the description of the invention. It is, therefore, 
contemplated that the appended claims will cover such modifications that 
fall within the scope of the invention.