Year: 1885

page_text: I, ROBERT CAMPBELL WILSON Ross, of 43 Raglan Street, Glasgow, in, the
County of Lanark, North Britain, Engineer, do hereby declare the nature of this
Invention to be as follows, that is to say:-
My said Invention has for its object by means of an improved construction.
of holder to facilitate the grinding of the ends of twist drills with accuracy, and
uniformity.
In carrying out the Invention the emery or other grinding wheel being on a
borizontal spindle and made with a cylindrical grinding surface, there is fitted on
guides so as to be movable in a direction parallel to the axis of the grinding wheel
but at a lower level, a saddle or slide having fitted on it a cross slide movable by means
of a screw spindle so as to move the drill nearer to or further from the grinding
wheel. Upon the cross slide there is fitted so as to be turnable about a vertical
axis a short horizontal cylindrical holder having fitted in and passing through it a
horizontal tube in which the drill to be operated on is fixed. A lever arm fixed in
the tube projects through a helical slot in the holder and by moving this lever arm
the tube with the drill can be turned and is at the same time moved forwards or
backwards. The tube with the drill is always directed with a considerable inclina-
tion in the horizontal plane towards the grinding wheel so that the requisite
approximately conical form may be given to the end of the drill; but this inclina-
tion is slightly varied whilst the drill is being turned over in order to form a short
ridge at the point. For the purpose of thus varying the inclination there is fixed
on the tube a sector-shaped plate having a curved or cam slot formed in it of a
suitable shape. A pin passing through the cam slot is fixed to a small swivelling
block which is adjustably, attached to the cross slide; and by adjusting the attach-
ment of this swivelling block the general inclination of the drill can be varied,
accordingly as it is wished to make the conical end of the drill more or less acute.
A hand lever is applied in connection with the bottom saddle or slide by means of
which the drill can be moved across the grinding wheel for the purpose of
equalising the wear of its surface.

page_text: Improvements, in Holders for Presenting Twist Drills to
Grinding Wheels.
I, ROBERT CAMPBELL WILSON Ross, of 43 Raglan Street, Glasgow, in the
County, of, Lanark, North Britain, Engineer, 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 andi by the following statement, that is to say :—
My said Invention has for its object by means of an improved construction of
holder to facilitate the grinding of the ends of twist drills with accuracy and
uniformity.
In carrying out my Invention the emery or other grinding wheel being on .a.
horizontal spindle and made with a cylindrical grinding surface, the improved tool
holder is arranged to present the drill to the grinding surface in the necessary
inclined position in a horizontal plane, whilst a peculiar combination of movements'
is imparted by means of a hand lever so as to give the desired approximately
conical form to one side of the drill point, the drill being turned half round in the
holder, in order to have the opposite side ground..
A grinding machine fitted with my improved, drill holder is shown on the accom-
panying sheet of explanatory drawings, figure, 1, being a plan, and figures, 2, and 3,
side, and front elevations; whilst figure, 4,. is a plan of the holder as slightly
modified. In these drawings the same reference numerals are used to mark the
same or like parts wherever they are repeated.
The parts forming the tool holder, are fitted upon a saddle or slide, 5, capable of
moving horizontally on V-guides parallel to the axis of the grinding wheel, 6, but
at a lower level and these guides are on a slide, 7, movable at right angles to the
saddle, 5, on V-guides formed on a part, 8, fixed to or cast on the table, 9, of the
machine. The slide, 7, is movable by a screw spindle and handwheel, 10, so as to
adjust the drill, 11, nearer to or further from the axis of the grinding wheel, 6,
whilst the upper slide, or, saddle, 5, is by means of a link, 12, and hand lever, 13,
moved, transversely to carry the drill point across the face of the grinding wheel, 6,
so as to equalise the wear on the grinding wheel.
Upon the upper saddle or slide, 5, there is fitted, so as to be turnable about a
vertical axis a short horizontal cylindrical 'holder, 14, formed with a foot which is
inserted into a vertical cylindrical socket formed on the slide, 5, and which is
secured by screw pins, 15, entered through the sides of the socket and projecting
into a groove formed round the holder foot. The holder, 14, has fitted in and
passing through it a bush or short tube, 16, and this bush, 16, has passing through
it an inner tube, 17, in which the drill, 11, is fixed. The inner tube, 17, is retained
in the bush, 16, by a collar formed on it and bearing on the front or inner end of
the bush and by a ring, 18, fixed on it by a pinching screw, 19, after it has been
inserted and bearing on the other end of the bush. A handled pin, 20, is inserted
through the bush; 16, so as to project into one of two diametrically opposite holes
in the inner tube, 17, to retain that tube and the drill, 11, fixed in it in the proper
position relatively to the bush, 16, for having one or other of the opposite sides of
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page_text: the drill point acted on. A lever arm, 21, is fixed in the bush, 16, and projects
through a helical or inclined slot, 22, formed for it in the holder, 14; and by moving
this lever arm the bush, 16, with the tube, 17, and drill, 11, are turned and at the
same time moved a little forwards and backwards. This combined turning and
end-on movement assists with other actions in causing the drill point to be ground
with the desired modified conical form. The inclination of the drill, 11, to the
grinding wheel, 6, in the horizontal plane is slightly varied whilst the drill is being
turned by means of the hand lever, 21, so that a short ridge may be formed at
the point of the drill. For the purpose of thus varying the horizontal inclination
there is fixed or formed on the bush or tube, 16, a sector-shaped flange or plate, 23,
having a curved or cam slot formed in it of a suitable shape. The cam slot is arc
shaped but placed with a small eccentricity so that its lower end is nearer the axis
of the bush, 16, the shape may, however, be varied in different cases. A pin, 24,
passing through the cam slot is fixed to a swivelling block, 25, which is adjustably
attached to the saddle or slide, 5; and as the bush, 16, is turned the cam slot in
its sector, 23, causes that part of the bush to move a little nearer to or further from
the adjustable block, 25, the holder, 14, being thereby turned slightly about its
vertical axis. The block, 25, is jointed to a pin, 26, which can be adjusted and
fixed at any part of a curved slot, 27, formed in a part of the saddle or slide, 5.
Instead of a helical slot, 22, being formed in the holder, 14, through which the
band lever, 21, is fixed into the bush or tube, 16, the holder, 14, may be made with
helical or inclined ends as shown in figure, 4, the hand lever, 21, being fixed into
the bush, 16, close to one end of the holder whilst a pin, 26, is fixed in the bush
close to the other end of the holder so as to cause the drill to return to the left
hand or inwards when the hand lever, 21, is turned over to the right hand (that
is to the upper side in figure, 4).
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,
The combination of parts forming my improved drill holder substantially as
herein before described.