Improvements in Circular Saws.
Year: 1890

page_text: Date of Application, 28th Feb., 1890
Complete Specification Left, 20th Aug., 1890-Accepted, 20th Sept., 1890
PROVISIONAL SPECIFICATION
Improvements in Circular Saws.
I, JOSEPH ELTON BOTT, of Eyam, in the County of Derby, Metallurgist, do
hereby declare the nature of this invention to be as follows:-
The invention has for its object, improvements in circular saws whereby they are
enabled, not only to cut up material, but also at the same time, to produce planed and
finished surfaces on the faces of the material on each side of the saw.
For this purpose I form the saw with ordinary saw teeth and with planing teeth, a
number of saw teeth (preferably four) alternating with a single planing tooth or cutter.
The saw teeth are as usual formed with cutting edges at their points and they are
"set" alternately to each side of the saw, whilst the planing teeth are of considerable
length and are set and have the cutting edges alternately along one or other
side of the periphery or outer edge of each planing cutter.
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A deep space or gullet is formed between each set of saw teeth and each adjacent
planing tooth or cutter to the front and to the rear thereof, and the periphery, outer
edge, or back of each planing tooth or cutter, gradually recedes from the point thereof
to the rear, where it meets the deep gullet between it and the following set of saw
teeth, so as to produce a draw cut.
In order to stiffen the saw, I raise curved ribs, alternately on each side thereof, one
of such ribs being formed a short distance from the periphery, outer edge, or back of
each planing tooth or cutter, and of somewhat considerable length; these stiffening
ribs also act to smooth or polish the planned surfaces.
Dated February 28 1890
COMPLETE SPECIFICATION.
Improvements in Circular Saws.
I, JOSEPH ELTON BOTT, of Eyam, in the County of Derby, Metallurgist, do
hereby declare the nature of this invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the following
statement:
The invention has for its object improvements in circular saws whereby they are
enabled not only to cut up material but also at the same time to produce planed and
finished surfaces on the faces of the material on each side of the saw.
For this purpose I form the saw with ordinary saw teeth and with planing teeth, a
number of saw teeth (preferably from three to six) alternating with a single planing*
tooth or cutter. The saw teeth are as usual formed with cutting edges at their points
and they may be "set" alternately to each side of the saw, whilst the planing teeth
are of considerable length and are "set" and have the cutting edges alternately along
one or other side of the periphery or outer edge or back of each planing cutter. A
space or gullet is formed between each set of saw teeth and each adjacent planing
tooth or cutter to the front and to the rear thereof, and the periphery, outer eige, or
back of each planing tooth or cutter gradually recedes from the point thereof to the
rear, where it meets the gullet between it and the following set of saw teeth, so as to
produce a draw cut.
In order to stiffen the saw I raise curved ribs alternately on each side thereof, one
of such ribs being formed a short distance from the periphery, outer edge, or back of

page_text: Figure 1 is a side view, Figure 2 is an edge view, and Figure 3 is a cross section, of
part of a circular ripping saw constructed according to my invention, and Figures 4, 5
and 6 are similar views of a circular cross cut saw also formed according to my
invention.
In all the figures like parts are indicated by similar letters of reference.
a, a, represent the saw teeth, which are preferably arranged in sets of three or more,
sets of three being shown in the saw represented at Figures 1, 2, 3, and sets of six in
that shown at Figures 4, 5, 6. The saw teeth a, a, are formed with the usual cutting
edges at their points, but the "set" usually given to such teeth alternately on each
side of the saw is dispensed with in those shown in the drawing. The planing teeth
or cutters 6 are of considerable length and are very slightly "set" alternately to one
and to the other side of the saw and they have their cutting edges formed alternately
along one or other side of their periphery, outer edge, or back b¹.
A deep space or gullet e is formed between each set of saw teeth a and the front or:
point of each planing tooth or cutter b, and a space, or gullet c', more or less deep
according to the character of the saw, is made between the rear of each planing tooth
or cutter and the first of the set of saw teeth a to the rear thereof, whilst the
periphery, outer edge or back b¹ of each planing tooth or cutter 6 gradually recedes
from the point or nose thereof to the rear, where it meets the gullet c¹ between it
and the following set of saw teeth a, so as to produce a draw cut.
In order to stiffen the saw I raise, as represented at Figures 1, 2, 3, curved ribs d
alternately on each side thereof, one of such ribs being formed a short distance from
the periphery, outer edge, or back of each planing tooth or cutter b and of
somewhat considerable length; these stiffening ribs are made to project at their outer
ends but very slightly from the plane of the saw, whilst such projection gradually
decreases to their inner ends. In addition to stiffening the saw, these ribs & also act
to smooth or polish the planed surfaces.
I have not represented these ribs d as applied to the cross cut saw shown at
Figures 4, 5, 6, but if desired thay may also be formed on such saw.
The saw teeth of the ripping saw shown at Figures 1, 2, 3, are, as is usual in
ordinary ripping saws, sharpened nearly square across their points or front edges,
whilst the saw teeth of the cross cut saw shown at Figures 4, 5, 6, are, as is usuaĺ
with other cross cut saws, sharpened at a more acute angle.
The planing teeth or cutters 6 of the ripping saw, as will be seen by reference to
Figure 1, are sharpened at a comparatively slight angle across their peripheries, outer
edges, or backs, whilst those of the cross cut saw, as will be seen by reference to
Figure 4, are sharpened at a much more acute angle.
I would here remark that the number of saw teeth in each set, and the shape,
dimensions and proportions of the same and of the planing teeth or cutters may be
varied without departing from the essential character of my invention.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim, is :-
1. In circular saws, the combination of planing teeth or cutters and saw teeth
or sets of saw teeth arranged in alternation, substantially as herein shown and
described.
2. In circular saws, the combination of planing teeth or cutters, stiffening and

page_text: polishing ribs, and saw teeth or sets of saw teeth arranged substantially as herein
shown and described.
3. In circular saws, the combination in alternation with saw teeth or sets of saw
teeth, of planing teeth or cutters having the cutting edge formed along one or
other side of the outer edge or back thereof, substantially as herein shown and
described.
Dated this 20th day of August 1890.
JOSEPH ELTON BOTT.
By Harris & Mills,
23, Southampton Buildings, London, Agents.