Improvements in Metal Working Tools and Holders for same.
Year: 1892

page_text: Date of Application, 19th Aug., 1892
Complete Specification Left, 16th May, 1393-Accepted, 17th June, 1893
PROVISIONAL SPECIFICATION.
Improvements in Metal Working Tools and Holders for same.
I, CARL JOHANN LAURENTZ LEFFLER of Havelock Street, Sheffield, in the
County of York, Metal Agent, do hereby declare the nature of my invention to be
as follows:-
My invention relates to improvements in the construction of tools for metal working
(such for example as turning and planing metals) and in the holders for such tools,
the object being to provide a permanent holder having a removable cutting point or
edge that can be made of exceedingly hard and durable metal, and that when worn
down or otherwise rendered useless, or when a different shape or size of cutting
point or edge is required, can be detached, and be replaced with another, thus
avoiding waste of time and material, as such removable points or tools can be kept
in working condition ready for use.
I propose for example to make a holder from a square bar of mild steel
of the required size, having in the upper side of its front end a deep D shaped
recess which may in some cases be carried completely through the holder, this
recess is to receive the shank of the point or tool. At the back of the recess, and
horizontally from side to side I make a cotter hole to receive a key and cotter, and
opening into the recess.
The point or tool consists of the face or cutting edge and the shank which fits
into the recess of the holder and may have a rounded projection on the back of the
shank to enter the cotter hole and engage with the concave face of the cotter which
is secured in position by driving in a key at the back of the cotter. The underside
of the face of the tool may be rounded off to the shank, so as to rest upon the
correspondingly rounded edge of the recess.
I prefer to make the front edge of the tool to overhang clear of the holder to
allow for reduction by grinding or wear.
Dated the 17th day of August 1892
ROBT. F. DRURY, C.P.A.,
Bank Buildings, George Street, Sheffield, Agent for Applicant.
COMPLETE SPECIFICATION.
Improvements in Metal Working Tools and Holders for same.
I, CARL JOHANN LAURENTZ LEFFLER of Havelock Street, Sheffield in the
County of York, Metal Agent 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:-
My invention relates to improvements in the construction of tools for metal
working, such as turning tools, planing tools and the like, and in the holders for such
tools, the object being to provide a permanent holder, and removable cutting points
or tools which are made of exceedingly hard and durable metal, so that when worn
down, or when otherwise become useless, or when a different form of cutting edge
is required, the point or tool can be removed from the holder and be replaced with
another, thus avoiding waste of time and material.
The annexed sheet of drawings illustrates a tool and holder made according to
my invention.
Fig. 1. is a side elevation of tool and holder.

page_text: In carrying out my
invention I make a holder H, from a bar of iron or steel of
suitable shape and size, having in the upper side of its front end a recess or
opening O, preferably D shaped, and passing either partially or completely through
the holder, the latter being preferred.
This opening is to receive the shank S, of the cutting point or tool T, and a cotter
hole is provided passing horizontally from side to side and opening into the recess
or opening O.
The holder if preferred may be cast to the required form and size in steel or in
malleable iron, and may be either straight as shown, or knee shaped, cranked or of
other form to suit the class of work. The cutting point or tool T consists of the
face F, with its cutting edge E, and the shank S, which fits into the holder.
The shank S, of the tool, inclines backwards and is made longer at the bottom
end than at the top, that is it increases in its width, from its junction with the
face F, to its bottom end, so that the action of the key K, and cotter C, when
driven in, will be against the inclined flat back of the shank drawing the underside
of the face F, firmly against the corresponding upper side of the holder, so as to
constitute a perfectly solid tool.
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-A metal-working tool, consisting of a detachable point or cutter T, with
shank S, fitting into a corresponding shaped opening O, in the end of a straight
or other form of permanent tool holder H, and secured by means of a key K, and
cotter C, or other equivalent device, substantially as hereinbefore described, and
with reference to the drawings.
2-As part of a metal working tool a detachable point or cutter consisting of a
face with a cutting edge of any desired shape, having a backwardly inclining shank,
tapering in its thickness but increasing in width from its junction with the head,
the back of the shank being flat to engage with a cotter or key or like fastener.
Dated the 13th day of May 1893.
ROBT. F. DRURY, C.P.A.,
Bank Buildings, George Street, Sheffield, Agent for Applicant.