IMPROVED MACHINERY FOR SHARPENING SAWS
Year: 1866

page_text: LETTERS PATENT to Edward Hammond Bentall, of Heybridge, near
Maldon, in the County of Essex, Agricultural Implement Maker, for the
Invention of "IMPROVED MACHINERY FOR SHARPENING SAWS."
Sealed the 11th January 1867, and dated the 26th July 1866.
PROVISIONAL SPECIFICATION left by the said Edward Hammond
Bentall at the Office of the Commissioners of Patents, with his Petition,
on the 26th July 1866.
I, EDWARD HAMMOND BENTALL, of Heybridge, near Maldon, in the
County of Essex, Agricultural Implement Maker, do hereby declare the
nature of the said Invention for "IMPROVED MACHINERY FOR SHARPENING SAWS,"
to be as follows:-
The object of this Invention is to provide machinery which will facilitate
the operation of cutting or sharpening the teeth of rotary and straight saws,
and maintain the same shape of tooth throughout, instead of their varying as
at present with the wear of the cutter or emery wheel; this wheel I mount
on the end of the carriage, which bears upon a horizontal slide carried upon
the top of a circular pillar or central standard. A traversing screw fitted to
the slide is used to give an endway motion to the carriage for the purpose of
In order to give the
moving the emery wheel across the teeth of the saw.

page_text: carriage a lateral motion for the purpose of throwing the wheel or cutter to
one or the other side of the axis of the circular saw a transverse traversing
screw is fitted in bearings at the top of the pillar and caused to act upon the
slide. The saw to be sharpened, whether it be circular or straight, is carried
by a hollow rectangular frame which is fitted by a dovetailed ring coupling
to a ring slide that embraces the vertical pillar, and is capable of being secured
thereto at any required elevation. The ring slide is fitted with a spur pinion
which gears with a vertical rack on the pillar, and the pinion is operated and
held fast by a worm that works into a worm wheel on the axle of the spur
pinion. The rectangular frame is provided with a bearing to receive a
spindle on which the circular saw to be sharpened is clamped, and to the
other end of this spindle is keyed a dividing plate made to correspond to the
number of teeth on the saw. A spring catch controlled by a rock lever is
used to hold the dividing plate in position. For steadying the saw under the
action of the cutter the rectangular frame is grooved longitudinally to receive
an adjustable standard, which carries a clamp adjustable vertically thereon.
When the standard is brought up to position the clamp is made fast to the
saw by a clamping screw.
The above-described arrangement allows of the rectangular frame being
adjusted both vertically and radially with respect to the central pillar to
bring the saw to any desired angle under the cutting wheel to produce a
skew cut or chamfer on the top of the tooth, and it further permits of the
tilting of the frame, which is required when operating upon straight saws.
When straight saws are to be sharpened in this machine a suitably-shaped
clamp is provided for holding the saw; this clamp is mounted on a slide,
which is itself carried by a longitudinal V-faced plate secured to the
rectangular frame before mentioned. By means of a traversing screw the
clamp slide is caused to travel over the face of the longitudinal plate and
present the saw to the rotating emery wheel or cutter. Rotary motion is
given to this cutter by a band from a driving pulley carried on the cutter
carriage, and as this carriage has no vertical movement, and its traverse motion
is only such as will ensure the traverse of the cutting wheel over the saw
no arrangement is requisite for taking up the slack of belt which transmits
motion from overhead gear to the driving pulley. I would remark that
instead of providing for turning the rectangular open frame which carries the
saw I may give an axial motion to the cutter carriage or the supporting pillar,
and thus bring the cutter to any required angle with the saw for giving &
chamfer cut.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said 'Edward Hammond Bentall in the Great Seal Patent Office
on the 26th January 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, EDWARD
HAMMOND BENTALL, of Heybridge, near Maldon, in the County of Essex,
Agricultural Implement Maker, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of July, in the year of our Lord
One thousand eight hundred and sixty-six, in the thirtieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Edward Hammond Bentall, Her special licence that I, the said
Edward Hammond Bentall, my executors, administrators, and assigns, or such
others as I, the said Edward Hammond Bentall, my executors, administrators,
and assigns, should at any time agree with, and no others, from time to
time and at all times thereafter during the term therein expressed, should
and lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle of
Man, an Invention for "IMPROVED MACHINERY POR SHARPENING SAWS," upon.
the condition. (amongst others). tbat I, the said Edward Hammond Bentall, my.
executors or administrators, by an instrument in writing under my, or their,,
or one of their hands and seals, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same. was to be
performed, and cause the same to be filed in the Great Seal. Patent Office.
within six calendar months next and immediately after the date of the said,
Letters Patent.
NOW KNOW YE,, that I, the said Edward Hammond Bentall, do hereby.
declare the nature, of my said Invention, and in what manner the same.
is to be performed, to be particularly described. and ascertained in and
by the following statement, reference being had to the Drawing here-
unto annexed, and to the letters and figures marked thereon (that is to
say)-
The object, of this Invention is to provide machinery, which will facilitate
the operation of cutting, or sharpening. the teeth of circular or rotary,
and straight saws, and maintain, the same shape of tooth throughout,
instead of their varying as at present, with the wear of the cutter or emery.
wheel.
In the accompanying Drawings: Fig. 1 shews in front elevation my improved
machine adapted to the sharpening of the teeth of a circular saw; Fig. 2

page_text: is a plan view of the same; Fig. 3 is a side elevation of the machine; and
Fig. 4 is a partial cross section taken in the line 1, 2, of Fig. 3, and
shewing the central standard (which carries the various parts of the
mechanism) with some of its attachments in plan view; Figures 5 and 6 shew
appliances to be adapted to the machine when straight saws are intended to be
sharpened.
The cutting tool which I prefer to employ for cutting or sharpening
the teeth of the saw is what is known in the trade as the "
emery wheel."
The form of wheel which I employ is that of a flat disc with a rounded or it
may be a flat periphery. In the Drawings this wheel is shewn at A, and it
is secured to a horizontal spindle a mounted in bearings on the end of a
carriage B, which is supported and caused to move endwise when required
upon a horizontal slide C; this slide C is carried by a turn plate C*, which is
itself mounted upon the top of a circular pillar or central standard D. The
turn plate is formed with a rebated slot to receive a dovetail or flanged guide
formed on the under side of the slide C and at right angles to the guides in
which the carriage B is free to slide. The pillar standard D is cast hollow
and with a suitable foundation plate at its base, and into this hollow a
cylindrical projection on the under side of the turn plate fits. b is a traversing
screw working in a tapped lug fitted to the slide C and used to give an
endway motion of the carriage B for the purpose of moving the emery wheel
across the teeth of the saw. In order to give the carriage a lateral motion
for the purpose of throwing the wheel or cutter to one or the other side of the
axis of the circular saw a transverse traversing screw c is fitted in bearings in
the turn plate C* at the top of the pillar, and caused to act
through a tapped lug, with which it is fitted at its under side.
sharpened, whether it be circular or straight, is carried by a hollow rectangular
frame E; this frame is secured by nuts on T-headed screws fitting in a dove-
tailed ring groove formed in the face plate of a collar or ring slide F that
embraces the vertical pillar D, as shewn best at Fig. 4; this ring slide, ring, or
collar is capable of being secured to the pillar at any required elevation by a
set screw f. The ring slide F is also cast with a recess to admit of the
insertion therein of a spur pinion f¹, which is keyed to a spindle f*, having
its bearings in the sides of the recess. The pinion f¹ gears with a vertical
rack d cast on or attached to the pillar D, and the pinion is operated and
held fast by a worm f that works, into a worm wheel f" keyed on the
spindle of the spur pinion. The spindle of the worm f' turns in bearings
formed for it on the side of the recess, and its end is squared to receive a key
for rotating the spindle. The rectangular frame E is provided with a bearing
upon the slide
The saw to be

page_text: Eto receive a spindle g on which the circular saw G to be sharpened is
mounted in order that it may receive an intermittent axial motion to bring the
teeth severally under the action of the cutter. The saw is secured to the
spindle by being clamped between a fixed and adjustable collar g', g³, by
means of a nut, and to the other end of this spindle a dividing plate G* is
keyed. The periphery of this plate is provided with notches corresponding in
number to the number of teeth on the saw, and into the notches a spring
catch controlled by a rock lever is caused to take for the purpose of locking.
the dividing plate, and thus holding the saw in position. For steadying the
saw under the action of the cutter an adjustable standard H is employed;
this standard carries a clamp H* adjustable vertically thereon, and intended
to clip the saw near the part where the rotary cutter is acting. The
standard is held down to the frame E by a clamping screw and nut h, the
T-head of which screw slides in rebated grooves formed in the ends of the
frame E. When the standard is brought up to and secured in position, as
shewn at Fig. 1, the clamp His tightened by a clamping screw h*, and
thus serves to steady the saw while the cutter is travelling over it, the
saw being however free to turn to bring up the teeth in succession to be
sharpened.
The above-described arrangement allows of the rectangular frame E being
adjusted both vertically and radially with respect to the central pillar to bring
saws of various diameters to any desired angle under the cutting wheel, as
indicated by the blue lines in Fig. 7, A.being the cutting wheel in three different
but parallel positions; these movements of the frame E enable me to gullet the
teeth with a skew cut or chamfered cut, but by reason of the ring coupling,
which permits of the tilting of the frame, any required inclination of cut may
be given, which is important when operating upon straight saws. Rotary
motion is given to the cutter A by a band from a driving pulley B* mounted
on a spindle 6*, carried on the cutter carriage B; as this carriage has no
vertical movement, and its traverse is limited to the amount of motion requisite:
to ensure the traverse of the cutting wheel over the saw, no arrangement will
be needed for taking up the slack of the belt which transmits motion from
overhead gear to the driving pulley. I would remark that instead of pro-
viding for turning the rectangular open frame which carries the saw around
the central pillar I may turn the cutter carriage, and thus bring the cutter to
any required angle with respect to the saw for the purpose of giving a
chamfer cut; this motion I have provided for by mounting the slide C on the
turntable C, which when adjusted to its required position must be secured
by a set screw c* or its equivalent.

page_text: When straight saws are to be sharpened in the above-described machine
the standard H is to be removed and replaced by the bracket plate and slide
attachment shewn in side elevation and cross section at Figures 5 and 6, for
the purpose of holding the saw and presenting it to the action of the cutter.
I is a bracket plate made fast to the rectangular frame E by T-headed clamp-
ing screws and nuts i, i, slidden into the dovetail longitudinal grooves of the
frame. The inner face of the frame I is furnished with horizontal rebated
guides which carry a slide 1*, and between this slide and a clamping plate I¹
the saw to be sharpened is made fast. By means of a traversing screw i¹
having its bearings in the plate I, and working through a tapped eye bolt
affixed to the slide I*, the slide with its clamping plate is caused to travel
over the face of the longitudinal plate I and present the saw to the action of
the traversing emery wheel or cutter. To ensure an equable intermittent
progressive motion of the saw the traverse screw may be fitted with a
dividing plate for determining by means of a spring stop (as already described)
the amount of axial motion imparted to the screw to bring the teeth of the
saw successively under the action of the cutter.
Having now set forth the nature of my Invention of improved machinery
for sharpening saws, and explained the manner of carrying the same into
effect, I wish it to be understood that under the above in part recited Letters
Patent I claim, the arrangements of machinery above described, whereby I am
enabled to sharpen the square and bevilled teeth of circular and straight saws,
and maintain the uniformity of their form throughout the saw without regard
to the wear or abrasion of the cutter or emery wheel.
In witness whereof, I, the said Edward Hammond Bentall, have
hereunto set my hand and seal, the Twenty-fifth day of January,
in the year of our Lord One thousand eight hundred and sixty-
seven.
E. H. BENTALL. (L.S.)