Year: 1875

page_text: made in each end of the saw blade to take on to these pins. The notch
in one end of the saw blade is made at an angle of inclination to the
cutting edge of the saw, so that when the saw blade is stretched it
cannot be forced off the pin. Or the same object may be effected by
cutting the end of the saw at an acute angle to the cutting edge thereof,
and forming the inner end of the notch in the handle of corresponding
forms. The notch at the other end is made at right angles to the cutting
edge of the saw, and simply to drop on to the pin in the handle, the saw
being fixed in position by the action of tightening up the same. This
is effected as follows:-The projecting part of the handle in which the
end of the saw blade is held by the pin is formed of a square or other
shaped spindle passing through a like shaped aperture in the outer part
of the handle. The outer end of this spindle is furnished with a screw
thread, upon which is worked a nut butting against the outer part of
the handle, so that by turning the nut in the direction to screw it into
the spindle the spindle will be drawn into the handle, tightening up the
saw blade, and at the same time locking it in the notch of the spindle.
Or instead of fixing the saw as described the end may be notched and
inserted into a groove formed in the handle, which handle is provided
with a spring to take into the said notch, and thus hold the saw.
In order to hold the handles firm in the frame, and at the same time
allow them to be turned round when required, a saw cut is passed
through the ends of the frame, so as to cause them to bite on the
handles with a spring action. Or the holes in the extremities of the
frame may be lined with india-rubber tube, or other spring action may
be used to tighten the hold on the handles.
In order to have the frames as light as possible, I prefer to make
them up to using solid material, this may be done in various ways.
One method is to have the two sides joined by two stretchers at the ends
opposite to the saw blade, the inner one to take the strain of tightening
up the saw, and the outer or upper to tie together the ends of the two
sides. If one piece of bent wood is used I prefer to let in or add to the top
a thin plate or bar of steel or other material, thus greatly strengthening
the frame with but a small addition of weight. I find in practice a
tubular metal frame both light and strong. The same may be formed by
stamping out the two halves of the tube longitudinally with a flange on
one or both sides, and fastening them together by rivetting or soldering,
or by other suitable means.

page_text: The handles I form very simply as follows:-I bore a hole lengthwise
through the wooden part of the handle, and insert from the outer end
inwards a piece of ordinary rolled metal, spread at the back end to
prevent it going further through than required, and of sufficient length
to project far enough through to form the portion of the handle to be
passed through the extremities of the frame and hold the screw blade. If
square metal is used for this a small piece of round tubing is fixed on
that part of it which turns in the extremity of the frame.
I provide for flexibility of the saw blade by placing an india-rubber
washer, helical, or other spring, between the extremities of the frame
and the shoulders on the handles of the saw.