A Double Handsaw with Adjustable Frame for Cutting Tenons.
Year: 1888

page_text: Date of Application, 11th Jan., 1888
Specification Accepted, 17th Feb., 1888
CUMI LEIE SPECIFICATION.
A Double Handsaw with Adjustable Frame for Cutting Tenons.
I, THOMAS FORSAITH of Adelaide in the Province of South Australia Machinist
do hereby declare the nature of my invention for "A DOUBLE HANDSAW WITH
ADJUSTABLE FRAME FOR CUTTING TENONS" and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement:-
My invention relates to hand saws for cutting tenons in wood. It has been the
practice in cutting tenons to use a saw having a single blade, and after making the
cut on one side care and skill has been necessary in making the second cut parallel to
the first. Besides when a number of tenons have been required to be cut of the same
size careful measurement has been necessary. The object of my invention is to avoid
these difficulties by constructing a tenon saw with two blades attached to a frame and
so arranged that they can be set at any desired distance apart in order to cut tenons
of different widths. By the use of my invention the two sides of the tenon are
always parallel and once the saw blades are fixed any number of tenons can be cut of
the same width.
By reference to the accompanying drawings it will be seen that Fig. I, is a side
elevation of a double tenon saw. Fig. II, an end elevation of an adjusting frame.
Fig. III side and end view of the adjusting clips. A, A¹, (Figs. I and II) are tenon
saw blades. B, front piece. C, adjusting screws and nuts. D, back piece. E, main
beam. F straining bar. G, Handle. H, (Fig. III) adjusting clips. The front
piece B, consists of a flat piece of metal or other suitable material to the parallel si:les
of the lower end of which the saws are secured by the adjusting screw C. The back-
piece D, consists of a further piece of similar metal firmly secured to a wooden handle
In the usual manner and provided with a similar screwnut C. To the back piece D,
s forged the main beam E, consisting of a round or flat bar provided at its outer
extremity with a double joint by means of which it is secured to the front piece B, in
such manner as will allow of the latter oscillating. The straining rod F, passes
hrough B, and D, and is provided with a head and screw nut or it may be in two
pieces connected in the centre with a screw swivel in the ordinary manner.
The adjusting clips H, are made in pairs of various widths preferably corresponding
with the sizes of the chisels of mortising machines, and are constructed to fit accurately

page_text: upon the front and back pieces B, and D. 'When it is desired to alter the width of
the tenon to be cut the screw nuts C, are loosened and adjusting clip H, of the
required thickness placed upon B, and D. The screws C, are then replaced and the
saws brought to the desired tension by means of the straining bar F. It will be readily
perceived that the two saws being set parallel the sides of the tenon must always be
cut equally so and that once the saws are set to any. required distance apart any
number of tensions can be cut of an exactly similar width. The saws and frame may
be made of any convenient size and of any suitable material.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I declare that what
I claim is :-
First. The method of cutting tenons in wood by means of a hand saw having two
blades set parallel to each other substantially as herein described.
Second. The construction of the frame of double tenon saws consisting of front
and back pieces B, and D), having parallel sides together with a jointed main bar E,
and a straining rod F, substantially as herein described.
Third. The adjustable clips H, in combination with the front and end pieces B,
and D, substantially as herein described and for the purpose indicated.
Dated this T
of Decomber
1800
Witness,
(21) TOHOT
חז ï060Tממז 001
THOS. C. CHELAND,
Public Notary,
Adelaide, S.A.
THOS. FORSAITH.