Improvements in or relating to Gauges for Use in Marking Out and Testing Rotary Cutters, and for Making similar Angular Measurements.
Year: 1896

page_text: Date of Application, 24th Feb., 1896-Accepted, 18th Apr., 1896
COMPLETE SPECIFICATION.
Improvements in or relating to Gauges for Use in Marking Out
and Testing Rotary Cutters, and for Making similar Angular
Measurements.
I, CHARLES LOUIS GOEHRING, of Alleghany, in the County of Alleghany,
State of Pennsylvania, United States of America, Doctor of Medicine, 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:-
This invention relates to improvements in gauges for facilitating the formation
and testing the accuracy of rotary cutters or knives, such for instance as are used
in wood-working machinery and have helicoidal or spiral cutting-edges, and more
especially knives of this character having a straight grinding surface; such tools
are hereinafter referred to generically as
cutters.'
The object of this invention is to provide an instrument with which the angle of
the grinding surface and position of the cutting edge on the cutter may be quickly
and easily indicated for forming the same, or tested subsequently, for example after
the cutter has been reground or sharpened.
Referring by way of example to the accompanying drawings:-
Figure 1 is a side elevation of a device embodying the present invention, showing
a cutter-head and cutters in position on the gauge.
Figure 2 is an end elevation, and
Figure 3 a vertical longitudinal section of the same,
Figure 4 being a transverse section taken through the cutter head to show the
position of the indicator hereinafter referred to in testing the angle of the grinding
surface relatively to the contour of the cutter or to its radius from the cutter-head
axis.
Figure 5 is a perspective view of the divided shaft A hereinafter referred
to, and
Figure 6 is an end elevation of a cutter blank to which the gauge is applicable
as hereinafter explained.
Like letters indicate like parts throughout the drawings.
Cutters such as it is the object of this invention to provide a means for testing
and marking, have commonly a helicoidal or spiral cutting-edge, and in order to
produce a cutting edge which will have a certain effect on the work, such for
instance as the production of a plane surface, it is necessary that the angles at
which the grinding surface is formed relatively to the contour or periphery of the
cutter and to the axis about which the cutter turns should be determined and
preserved with the utmost accuracy, as the least variation in these angles or in
either the disposition or degree of curvature of the edge will change the character
of the work produced. Such cutters can be produced with a plane grinding
surface, by which is meant a surface lying in one plane and ground to intersect
the contour of the cutter to produce the cutting edge and in order to determine
the situation of the plane which is to form this grinding surface the cutter head
carrying the cutters is mounted upon a spindle in the position in which they will
operate this spindle centres the cutter head. Previous computations determine
the cutting angle of the cutter (i.e. the angle between the ground surface and the
contour of the cutter) and the angularity with which the plane of the grinding

page_text: surface intersects transversely the axis of the spindle, and preferably, suitable
segments are mounted at the ends of the spindle and provided with graduations
and with pointers for registering therewith; these pointers may be set at the
predetermined angle which opposite ends of the cutting edge make with each other
and they so control an indicator registering with the cutter as to indicate at the
surface of the cutter itself the exact situation of the grinding surface to be made.
By providing a segment at each end of the spindle the proper point is indicated at
each end of the cutter, and the cutter after having been properly marked manually
may be removed and the necessary cutting or dressing of the grinding surface
performed in any ordinary or well-known manner, said cutting or dressing being
in certain instances in one plane passing through the indications or marks at each
end of the cutter, although it may be so effected as to produce a helical or other
surface, if desired.
Referring now more particularly to the drawings, A indicates the main spindle
which is preferably divided longitudinally (as shown clearly in Figure 5) into two
parts A¹ A so as to permit of the cutter head A³ with cutters A being slipped
thereon without removing the two segments B, which are firmly secured to the
ends of the two parts of the spindle in a position which may be arbitrarily selected;
the two segments should be parallel and exactly opposite each other as shown.
Moreover the division of the spindle enables the segments B to be restored with
accuracy and certainty to their original relative positions simply by placing the
parts of the shaft together again after they have been taken apart; and it enables
the segments to be moved apart as may be necessary for the reception of cutters
of different widths between them.
The division of the spindle A need not be made exactly in the form indicated in
the drawings; any other mode of division may be adopted which will permit the
two parts of the spindle to be moved apart in some such manner as described and
ensure the parts going together again with accuracy.
The segments B are preferably-graduated in an arc from a central mark,
preferably indicated by the number 90, the graduations from this central or 90°
mark in each direction being of lower denomination successively. Mounted with
their axes coincident with the axis of the spindle A, and preferably on the spindle
itself as shown, or on a prolongation of the hubs of the segments B at each end,
are swinging arms C which may be turned to register with any of the graduations
on the segments, and these swinging arms C are in turn graduated longitudinally
as indicated at C. The bosses C2 of the swinging arms may be screw clamps as
shown, to facilitate their adjustment and to enable them to be securely held in the
positions to which they are adjusted.
Each swinging arm C is preferably cut away to form a straight slot C³ in which
is adapted to move in a radial line an indicator-carrier D having a pointer D¹
registering with the graduations C¹ and also having a clamping nut D² by means
of which the indicator carrier may be clamped in position at any point within its
range of movement. The construction of the particular indicator-carrier and
clamping-device illustrated in the drawings is hereinafter described in detail.,
although other appliances for like purposes can be substituted therefor without
departure from this invention.
On the inner portion D³ of the indicator-carrier a secondary segment E is
rigidly mounted which secondary segment it will be observed is carried on a
spindle E' adjustable lengthwise in the part D and capable of a radial movement
along the arm C with the indicator carrier D; thus the segment E moves with the
arm C about the axis of the spindle A, but is incapable of any swinging movement
on its own centre, and in effect it forms a rigid portion of the indicator carrier
itself and is adjusted therewith. This secondary segment E is provided with a
hub-like extension E and upon this extension there is pivoted a secondary
pointer F adapted to register with a series of graduatious E on the secondary
segment and having rigidly affixed thereto the indicator arm F¹. This indicator
arm is adjustable towards or away from the ends of the cutters A' by sliding the

page_text: shaft E endwise; the arm may be pointed but it is preferably made so that one
side of it is a plane surface as shown, the angularity of which surface relatively to
the arm C may be accurately adjusted as desired by moving the pointer F on the
secondary segment E and the angular adjustment of the pivot of the pointer F
about the spindle A and cutter head A' carried thereby may be accurately effected
to any predetermined degree by moving the swinging arm C to register with any
predetermined indication on the main segment B.
The indicator arm F when made in the form of a flat piece, as shown
in Figures 1 and 4 has one surface F in the plane of the axis about which the
arm turns and has a reference line F³ so marked on that plane as to be in the line
of that axis.
It will now be seen that having determined the size of the cutter to be made, the
two indicators F¹ may be set radially in the swinging arms C to be exactly
the same distance from the axis of the spindle A and may be moved end wise up to
the cutters after which with the guidance of their centre-lines F, marks may be
made on the ends of each cutter which will be exactly the same distance from the
centre or axis of rotation of the cutter head. By moving the swinging arms C
relatively to the main segments B the situation of the ends of the cutting edge
may be accurately determined if each swinging arm is caused to register with the
desired indication on the adjacent segment B; thus cutters may be set on the
cutter bead or tested for accuracy to the utmost nicety.
Where it is desirable to determine or indicate at the ends of the cutter
the cutting angle aforesaid, i.e. the angle formed by the line of intersection of the
grinding surface with a transverse plane perpendicular to the axis of rotation, and
a line passing in the same plane from the axis of rotation to the cutting edge it
may be done with great accuracy by setting the plane surfaces of the indicator
arms F by adjusting the pointers F on the secondary segments E; the plane
surface of the indicator arms F if set at the proper predetermined angle will serve
as a gauge by which the end of the cutter may be marked to show the cutting
angle aforesaid which may also be considered as the angle of the grinding surface
relatively to the contour of the cutter and if a cutter is being tested after grinding
it will show at a glance if that angle has been preserved.
With reference again to the indicator carriers D each one comprises two
blocks D D' flanged so that the arm C is received in the groove between the
flanges. The block D' carries the spindle E' which has a longitudinal groove Es
thereon into which a tongue D' on the block D enters. Thus the spindle E' can
be moved endwise through the block D' but cannot rotate therein. The block D'
carries as aforesaid the secondary segment E, a screw E being screwed through
the segment into the spindle E so that the segment shall not rotate. The
indicator and its pointer F are in one piece, placed on the hub of the
segment E and held against the segment by a screw F which passes freely
through a slot Es in the segment E into the pointer F. The head F of the
screw F prevents the pointer F and indicator F from moving off the hub Es
and the slot E enables the screw F' to move with the pointer F in rotation about
the hub E².
D is a tubular taper screw with slits therein which is screwed to the
block D³, D' is a nut adjustable thereon to cause the tubular screw to grip or
release the spindle E' so that the latter can be adjusted endwise as required in the
treatment of cutters of differing widths.
D is a nut adjustable on the screw D. When the latter is fixed on the
spindle E the former can be operated to move the two blocks D³ D' together so
as to grip the arm C between them and thus retain the indicator carrier D at any
position on the arm C to which it is adjusted.
In using this instrument it is only necessary to make tables for the various
forms of cutters used in any work and then set the pointers so as to bring the
indicators to the proper positions according to the tables. The instrument is
adapted for use in making and testing cutters for all styles of work and it may be

page_text: quickly set or changed to test or mark any of the various cutters. Its construc-
tion is simple and the manner of its use is so obvious as to require the services of
only an ordinary mechanic in its manipulation.
Although the gauge is hereinbefore described in its application to individual
cutters it is obviously of equal utility in the operation of scribing or marking off a
conical or circular or other blank which is intended for ultimate division into
-cutters.
A conical blank is shown in end elevation and properly scribed in Figure 6.
The lines indicate the marks on the end of the cone by which a milling tool or a
saw are guided to cut the blank into say four cutters along the dotted lines m, each
of which when thus cut will possess a grinding surface and cutting edge disposed at
the desired angle and in the desired plane.
"Slow-motion" screws or other adjusting devices may be applied to the
instrument if desired, to effect the rotation of the arms C, the movement of the
indicator-carriers D along those arms, or the adjustment of the indicator
pointers F. Verniers may also be applied to the several scales if desired.
Having now particularly described and ascertained the nature of the said inveu-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In a gauge for angular. measurements the combination of a main spindle,
radial arms such as C rotatable about its axis, indicator carriers such as D
adjustable along or carried upon the arms C and indicators such as F¹ with or
without index pointers and graduated scales for the purpose described.
2. In a gauge such as described indicators such as F¹ comprising plates adjust-
able to various angles relatively to the arms C for the purpose described.
3. In a gauge such as described a main spindle in two parts substantially as and
for the purposes described.
4. In a gauge for angular measurements an angle measuring apparatus_such
as B and C adjustable to different positions laterally for the purpose described.
5. In a gauge for angular measurements an angle measuring device such as B
and C in sets adjustable to different distances apart substantially as and for the
purpose described.
6. In a gauge such as described an angle measuring device such as the parts E
and F adjustable in the direction of the axis of the gauge for the purpose
described.
7. In a gauge such as described the combination and arrangement of parts
constituting an indicating device and comprising a carrier such as D indicator arm
such as F spindle such as E¹ and clamping devices for the spindle substantially as
described and illustrated in the accompanying drawings.
8. The combination and arrangement of parts constituting the complete gauge
substantially as and for the purpose described and illustrated in the accompanying
drawings.
Dated this 24th day of February 1896.
BOULT & WADE,
Agents for the Applicant.