Improvements in Tool Holders.
Year: 1892

page_text: Date of Application, 29th Aug., 1892-Accepted, 15th Oct., 1892
COMPLETE SPECIFICATION. -
Improvements in Tool Holders.
We, GEORGE ARMSTRONG, Manufacturer of the City of Chicago, County of
Cook, State of Illinois, and EDWIN VASEY, Gentleman, of Chadron, County of
Dawes, State of Nebraska, United States of America, 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 :-
Our invention relates to cutter- or tool-holders for lathes and planers. Its object
is to provide a holder for cutters used in connection with such tools which will
possess great strength; will present the cutter at the most effective angle; will
hold the cutter secure and prevent it from impinging upon the tool post or bed
plate should it slip back in the socket.
The invention consists essentially in the position and shape of the socket of the
holder or stock.
In the accompanying drawings,
Figure 1 shows a plan view of the tool post of a lathe or planer with our improved
holder in position for use;
Figure 2 is a central longitudinal vertical section of the same;
Figure 3 is a transverse section of the tool-holder on the line 3, 3 of Figure 2;
Figure 4 is a view in the direction of the arrows, partly in section on the line 4, 4
Figure 2.
We are aware that a variety of tool-holders have been made, but it has been
found difficult to design a stock for this purpose which will present the cutter to its
work at such an angle as to secure proper clearance, while obtaining ample strength
in the stock for heavy work. The purpose of this invention is to provide a stock
which will possess substantially the strength of the old style of cutters, in which the
cutter and stock were integral and the tool could be repeatedly resharpened only by
reforging, and will be available for use in any position in which the old style of cutter
could be used.
To this end we use an ordinary piece of bar steel A, for the holder or stock,
cutting a socket a¹ of peculiar shape back from the end of the bar at an angle
of conveniently between ten and twenty degrees to its top line, but in direction
parallel to its sides, the socket being continued so as to open through the bottom of
the bar A, as shown at e, but being formed with a shoulder E, near its inner end so
as to prevent the cutter-bar C, from projecting beyond the under surface of the
bar A. A boss a is formed upon the top of the bar A, near its forward end
to provide body within which to form a socket for the binding-screw B which bears
against the cutter bar C.
The stock is secured in the aperture of the tool-post D in the usual manner by
means of the binding screw d.
In forming the socket a¹ a drill is used to form a circular aperture of a diameter
somewhat greater than the width of the cutter bar. This socket is drilled from the
end of the bar A, the drilling is continued until the bottom of the bar is perforated
as shown ate, but not far enough for the drill to pass entirely through. The socket
is now squared to correspond to the size of the cutter bar, back to the juncture of
its lower side with the bottom of the bar A, thus forming a shoulder to prevent the
cutter bar from projecting beyond the bottom of the holder, and leaving a
longitudinal groove in each side of the socket.
The cutter is preferably of "self-hardening " steel. The bars of this steel are
not uniformly square, the sides being usually somewhat rounded or ribbed. If the
lower side of the socket is perfectly flat, an uneven bar will not rest firmly in its
place. The purpose of forming the sides of the socket with grooves is to
ת

page_text: accommodate the irregularities of the cutter bar by practically providing longitudinal
shoulders upon which it may rest as a seat. It will be found cheaper to groove all
of the sides in the manner described rather than the lower side only.
The purpose of the stop shoulder E is to prevent the hard cutter-bar from falling
back upon the floor of the tool-post or upon the tool ring when one is used, and
thereby locking the parts together very awkwardly, as has been found in practice;
while the socket is open through the bottom of the holder, so that the cutter bar
may, if necessary, be forced out.
As thus formed the tool-holder combines all of the advantages of the old form of
tool whose body formed the stock, and the tool-holders already known, without any
of the disadvantages of either form of construction.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. A tool-holder or stock having a tool socket extending from one of its ends
diagonally through its body at an angle approximately between ten and twenty
degrees to the longitudinal line thereof, and opening through the underside of the
stock said socket being rectangular in cross-section and having its lower side
longitudinally grooved and being provided with a stop shoulder near its inner end
whereby the tool is prevented from projecting beyond the bottom of the stock
substantially as described.
2. A tool-holder having a rectangular socket whose lower side is longitudinally
grooved substantially as described.
Dated this 20th der of Aurust 1802
W. P. THOMPSON & BOULT,
Agents for the Applicants.