An Improved Riming Tool.
Year: 1897

page_text: Date of Application, 1st Nov., 1897-Accepted, 5th Mar., 1898
An Improved Riming Tool.
I, ROBERT BRÜCK, of 111, Wilmersdorferstrasse, Charlottenburg, Germany,
Manufacturer, 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 an improved riming tool, the frictional action of which
is considerably greater than that of riming tools heretofore made and used. The
action of the improved riming tool is particularly effective in broaching holes
in steel, iron and wrought iron. In consequence of their tenacity these materials
can only be worked with riming tools of ordinary construction by a great expen-
diture of force, which causes the breaking of the friction surfaces and partly by
reason of such breakage and partly on account of the inadequate or faulty guiding
of the riming tool, the rimed holes are never formed entirely round and quite
smooth throughout.
This drawback is obviated by reason of the peculiar formation of the friction
or cutting edges of the riming tool which forms the subject of the present invention.
The action of the cutting edges in the improved riming tool is the same as in
a knife set obliquely so that there is no forcing away of the material as is the case
where ordinary riming tools are employed but an even or regular cut of the
material is produced.
In the accompanying drawings, Fig 1 is a side elevation of a riming tool con-
structed according to this invention. Figure 2 is a sectional elevation of same, and
Fig. 3 is a partial sectional elevation on an enlarged scale of an alternative form.
As will be seen by referring to Fig. 1 the cutting edges are arranged in a series
of three parallel screw courses inclined at an angle of about 45° to the direction
of rotation of the riming tool, the lower edges of profile being inclined at an
angle of 90°, i.e., at right angles, to the longitudinal axis of the rimer, as will
be clearly seen in Figs. 2 and 3. The whole breadth of the three parallel screw
courses lying one above the other is equal or rather less than one half of the pitch
so that the part diametrically opposite to any cutting surface of the riming tool
is a completely smooth guiding surface, hence it is impossible for the holes to
be otherwise than round when bored. The direction of the screw or thread courses
is opposite to the direction of rotation of the riming tool, so that the cutting edges
in a tool which is rotated to the right are formed by left hand threads and vice
versa. The thread or screw courses form simultaneously angular points as shown
in Fig. 2, or semi-circular grooves as shown in Fig. 3, these grooves serving to
carry off the waste cuttings and for the introduction of oil.
Besides giving a better result the improved riming tool has the further advan-
tage of great durability so that even where the hardest material is worked, it is
only in exceedingly rare cases that the cutting edges soften or crumble, the com-
plete breaking off of the cutting edges is impossible.

page_text: 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:-
A riming tool in which the cutting edges are formed by a series of parallel
screw courses the inclination of which is such that the whole width of the cutting
series is about or rather less than one half of the pitch, so that a proportionally
large and smooth surface is always opposite to the cutting edges, whilst the
cutting edges themselves are set in an opposite direction to the direction of rotation
of the tool substantially as described.
100K
F. W. GOLBY,
36, Chancery Lane, London, W.C., Patent Agent for the Applicant.