Volume 8, Issue 3 - January 2014
Bash the Tin Box
terms of the rapid rise in the high-tech world, there have been
consistent references to the "two guys in the basement"
and how innovation and determination changed and shaped how
information is stored and transmitted. But what about the ordinary
things? The new improved mousetrap with more than 7,000 approved
patents? And of course the lowly hammer, sitting at more than
one million patents. These are examples of how constant revision
is the driving force for any new concept. The same principle
applies in the tool world with the working tradesperson who
"sees the light", so to speak, and makes an improvement
to an everyday working tool. Such is the case with this item.
First the patent and then the story.
M. Hexdall of Morris, Indiana, sought with patent #2,606,468
dated April 29, 1949, to improve the methods used and the quality
of work done by those in the sheet-metal trade with the construction
of the purpose-built tinner's hammer. His distinctive approach
resulted in a hammer head that, upon manipulation, could work
into square recesses. It also provided a large striking surface
for working the flange in rectilinear joints, as normally found
in ductwork. As with most regulated and apprentice-driven trades,
change is most difficult. The appearance of a new tool to supplant
the old is never well received unless there is a possibility
of reaching a wide group via mass marketing and effective distribution.
Strangely, some 50 years later, this hammer has merit and could
probably be widely accepted as a first choice in the respected
the mid-1990s, this item was offered on a popular website and
made its way into the Lee Valley collection. Upon receiving
the hammer, it was a most pleasant surprise to find that the
history had been carefully recorded by a Mrs. Dale Hextell (note
spelling) and was included in the original packing box. The
photo shows a copy of the original handwritten note, as
found, with its full explanation as to the source and manufacture
of the hammer. On a separate sheet, the seller (who was not
Mrs. Hextell) indicated that there were about 25 units available
in this new old stock (N.O.S.) condition. I surmise that these
sold rather quickly, as hammer aficionados would jump at the
chance to own such a limited-production hammer with an American
patent and history. Normally by the time tools such as this
are rediscovered or sold, there is no record as to where and
how they came to be marketed. It is rather pleasant to know
the back story of this innovation.
A hand-written note, included in the box, explaining
the history of the item.
D.S. Orr has been a collector, user and student of woodworking
and metalworking tools and practices for more than 40 years.
Recently retired, he has devoted even more time to these endeavors.
Aug. 12, 1952
United States Patent Office
Sheet Metalworking Hammer
Andrew M. Hexdall, Morris, Ill.
Application April 28, 1949, Serial No. 90,085
2 Claims. (Cl. 81-15)
This application is a continuation-in-part of my copending application
Serial No. 14,661, now abandoned.
The invention relates to hand hammers generally, and more particularly
to an improved hammer for sheet metalworking.
The general object of the invention is to provide a hammer especially
suited for the various operations involved in the fabrication
and erection of sheet metal structures and which is constructed
so as to afford a feeling of balance and a resiliency or bounce
that makes it easier and less fatiguing in use.
A more specific object is to provide a hammer particularly well
adapted for completing Pittsburgh joints in sheet metal structures,
which can be used effectively in confined spaces and which is
universally adaptable for seating the driven flanges of either
right or left-hand joints and for other joint finishing operations
such as the lapping over of the second or locking flange.
Other objects and advantages of the invention will become apparent
from the following detailed description of the preferred embodiments
illustrated in the accompanying drawing, in which:
Figure 1 is a perspective view of a hammer embodying the features
of the invention, showing it in the left-hand position in seating
the driven flange of a Pittsburgh joint.
Fig. 2 is a perspective view of the hammer showing it in the
alternate or right-hand position.
Fig. 3 is a perspective view showing the use of the hammer in
lapping over the locking flange to finish the joint.
Fig. 4 is an end view of a modified form of the hammer shown
in Figs. 1-3.
Fig. 5 is an end view of a modified form of the hammer.
Two embodiments of the invention have been shown by way of illustration,
but it is not intended to thereby limit the invention to the
precise forms illustrated. On the contrary it is the intention
to cover all modifications and alternative constructions falling
within the spirit and scope of the invention as expressed in
the appended claims.
Referring to the drawing, the improved hammer has a head 10
which may be fashioned as a steel forging or may be milled from
bar stock, as desired. The head is centrally apertured as at
11 to receive the end of a wooden handle 12. Such handles are
commonly formed with a gripping portion 13 of generally oval
contour to conveniently fit the hand of the user. Preferably,
the end or shank portion of the handle and the aperture 11 in
the head are of circular cross section so that the handle may
be turned on its axis to orient the gripping portion for the
convenience of any user. The handle may be anchored to the head
and located in adjusted position by any suitable means, such
as a set screw 14 (Fig. 4). Alternatively, a conventional wedge
15 may be utilized for anchoring the handle to the head, as
shown in Fig. 5.
In accordance with the invention, at least three specially shaped
striking faces are provided on the head 10. One of these is
a relatively long striking face 16 fashioned on a side of the
head and terminating or blending into noses 17 of smoothly rounded
contour at each end. To provide the resiliency or bounce desirable
for reducing the shock and jar transmitted to the hand of the
user, the face 16 is preferably crowned or formed with a contour
a contour arcuate about an axis substantially parallel to the
axis of the handle and off-set therefrom and on the opposite
side thereof from the face. In general, a relatively small curvature
is all that is required and in practice it has been found that
such curvature may conveniently be formed on a radius in the
neighborhood of four inches.
The surface finishing of the striking face 16 is also important
in giving the hammer a well-balanced feeling and the correct
swing in use. More particularly, it has been found that the
best results in this respect are obtained when the striking
surface is finished by an abrading operation or the like which
leaves the surface slightly roughened and with a grain defined
by shallow ridges. The abrading tool is applied so that the
grain or ridges extend across the face in the direction of its
narrowed dimension or parallel to the handle. This enables the
pounding face to draw on the metal or hold back just enough
to impart a live feeling, which is highly desirable in metalworking
Two additional striking faces 20 and 21 are fashioned on opposite
ends of the head. These faces are disposed in substantially
parallel planes at right angles to the first-mentioned striking
face 16. The striking faces 20 and 21 are crowned similarly
to the face 16 and are finished with an abraded surface having
the grain extending across the narrow width of the face, in
this instance transversely of the axis of the hammer handle.
Preferably, the corners of these faces are rounded as shown
in Fig. 4.
To facilitate the use of the hammer in oppositely disposed crevices
or corners, the striking faces 20 and 21 are terminated at their
ends remote from the striking face 16 in abrupt shoulders 22
and 23. The intermediate portions of the head 10 on the side
opposite the face 16 are recessed as at 24 so as to present
the shoulders 22 and 23 in laterally projecting or off-set relation
with respect to the central portion of the head. Thus ample
clearance is provided for inserting the head into a corner.
At their other ends, the end striking faces are separated from
the side face 16 by the noses 17 which terminate inwardly from
the faces or are off-set so as to form narrow shoulders 171
substantially normal to the respective striking faces.
The facility with which the improved hammer may be used in confined
spaces will be readily seen by reference to Figs. 1 and 2 of
the drawings. Thus, in hammering in a left-hand corner (as viewed
from the handle end of the hammer) such as shown in Fig. 1,
the striking face 20 is used. The narrow shoulder 22 permits
the striking face to be applied relatively close to the edge
of the surface being pounded. In an oppositely disposed or right-hand
corner, the hammer head is turned through 180° about the
longitudinal axis of the handle from the position shown in Fig.
1 to the position shown in Fig. 2 and the striking face 21 is
used. This reversible characteristic of the hammer greatly aids
the worker, especially in confined quarters, when working overhead
or in the various awkward positions that a sheet metal installer
has to assume.
Pittsburgh joints are, of course, commonly used in sheet metal
duct work. As is well known, the sheets for such joints are
performed so that one sheet 25 has a first or driven flange
26 which must be hammered into a groove formed by a reverse
bend 27 in the other sheet 28, as shown in Figs. 1 and 2. Finally,
a second or locking flange 29 at the edge of the sheet 28 must
be bent or crimped over and smoothed down over the sheet 25
to complete the joint, as shown in Fig. 3.
Such seating of the driven flange 26 and lapping over of the
locking flange 29 has to be done on the job by hand during installation
of the sheet metal structure. The hammer here disclosed is especially
suitable for the performance of those operations. The peculiar
shape and location of the reversible end striking faces 20 and
21 make it possible to get into the corners between the sheet
25 and flange 29 and drive home the flange 26 wherever the work
is located. It can be done by this hammer with clean, sharp
blows without either marring the upstanding flange 29 or buckling
or distorting the sheet 25 at the root of the flange 26 or elsewhere.
Moreover, with the flange 26 driven home, the long striking
face 16 makes it possible to lap over the locking flange 29
in a neat, workmanlike manner and with a relatively small number
of strokes of the hammer. Because of the surface contour and
finish of the striking face 16, the feeling of balance and the
draw against the work enables the workman to attain maximum
production with less effort and with maximum fatigue.
In some instances it may be desirable to provide the hammer
with a fourth or auxiliary striking face 30, which additionally
serves as an anvil or backing surface against which a metal
sheet or the like may be pounded to remove irregularities. The
face 30 is formed on the side of the head 10 opposite the face
16 and is preferably flat and smooth as shown in Fig. 5. In
this case the end faces 20 and 21 are merged into the face 30
by gently rounded corners 31. Since all four sides of the head
present pounding faces in this instance, the handle 12 is anchored
to the head by means of the wedge 15.
I claim as my invention:
A sheet metal hammer comprising a metal head apertured
centrally to receive a handle, said head having an elongated
generally flat lateral surface disposed in a plane approximately
parallel to the axis of the handle aperture, a pair of
generally flat end surfaces substantially shorter than
said lateral surface, said end surfaces lying in planes
laterally offset from and substantially parallel to the
axis of the handle aperture, said lateral surfaces merging
at opposite ends into said end surfaces by way of smoothly
curved corner portions which are offset inwardly with
respect to the end surfaces, the end portions of said
head having lateral extensions at the side opposite said
lateral surface defining shoulders projecting substantially
beyond the portion of the head between the shoulders.
A sheet metal working hammer comprising, in combination,
an elongated head defining abrupt shoulders at opposite
ends thereof at sides opposite from said side face, said
end faces being substantially commensurate in width with
said head and extending from said respective shoulders
to extremities disposed somewhat inwardly of the adjacent
ends of said side face, and two curved nose portions on
said head disposed in bridging relations between said
respective end faces and adjacent ends of said side surface.
The following references are of record in the file of this
United States Patents
|Feb. 3, 1880
Jan. 21, 1890
May 21, 1901
Jan. 11, 1910
May 17, 1910
Aug. 23, 1910
Sept. 8, 1931
Mar. 1, 1932