Improvements in Reamers.
Year: 1891

page_text: PROVISIONAL SPECIFICATION.
Improvements in Reamers.
I, BENJAMIN BENTLEY ALLEN, residing at Nashville, in the County of
Davidson and State of Tennessee, United States of America, Capitalist, do hereby
declare the nature of this invention to be as follows
My invention relates to reamers or revolving cutters for boring boxes or bosses
to receive shafting, so constructed that they can be readily and securely fixed on
the mandrils which drive them, and can have their cutting teeth easily and truly
ground by an ordinary grindstone.
The body of the reamer, which has several cutting wings projecting from it, five
being a convenient number, is bored to fit on a cylindrical mandril against a shoulder
the meeting faces of the reamer and shoulder being so formed as to engage with
each other as a clutch. In front of the reamer is fitted on the mandril a cylindrical
sleeve which can enter the hole to be bored and serve as a guide. The sleeve and
reamer are clamped on the mandril by a mut screwed on its end. Each cutting
wing of the reamer has a flat face radial and parallel to the axis which face can be
ground by passing it tangentially along the periphery of a grindstone.
Each wing has its side face bevilled, forming an angle less than a right angle
with the front face so as to present a cutting edge, and this oblique face can also
be ground on the grindstone.
The front and side faces and cutting edge may be those of steel blades adjustably
bolted on the wings of the reamer.
Dated this 27th day of June 1891.
ABEL & IMKAI,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Reamers.
I, BENJAMIN BENTLEY ALLEN residing at Nashville in the County of
Davidson and State of Tennessee United States of America, Capitalist, 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 reamers or revolving cutters for boring boxes or bosses
to receive shafting, so constructed that they can be readily and securely fixed on
the mandrels which drive them, and can have their cutting teeth easily and truly
ground by an ordinary grindstone, as I shall describe referring to the accompanying
drawings.
Fig. 1 is a side elevation and Fig. 2 is a longitudinal section of a reamer con-
structed according to my invention.

page_text: Figs. 3 and 4 are perspective views looking at the front and back respectively of
the cutter head.
Fig. 5 is a diagram illustrating the manner of grinding the front face and one end
of a cutter-tooth for producing the sharp cutting edge.
Fig. 6 is a front and Fig. 7 a side view shewing the cutter made with adjustable
cutting teeth.
1, indicates the mandrel having a collar 2 and a cylindrical shank 3 terminating
in a screw-threaded stem 4. The front face of the collar 2 is formed with recesses 5
to receive and interlock with the shoulders 6, projecting from the rear face of the
cutter head 7. Thus the cutter is clutched to the mandrel and the weakest part of
the cutter where it is bored to receive the shank 3 is relieved of strain.
The cutter shewn has five radial teeth, but a greater or less number of teeth
may be employed, so long as there are enough to cut a true circular bore, as when the
cutter is revolved for enlarging the hole in a cast shaft-boxing after the sand has
becu removed from it. Each tooth has a straight face 8 and a bevelled or oblique
front 9 which slopes back at an acute angle from the face 8 so that the straight
cutting edge 10 is radial and at right angles to the longitudinal axis of the mandrel..
The faces 8 are in planes passing through the axis of the mandrel, and as the
oblique or bevelled front ends of the teeth extend back at acute angles to the faces
of the teeth, the cutter can be conveniently, rapidly, and efficiently sharpened by
means of an ordinary circular grindstone as indicated by the dotted lines 12 in
Fig. 5. Under the bevelled faces 9 there are shoulders 13 which serve as guides
for the grindstone while grinding these faces 9. Also the rear faces 14 serve as
guides for the grindstone when grinding the front faces S to sharpen the cutting-
edges 10.
The cutting-edges of the tool can thus be readily sharpened by means of an
ordinary circular grindstone without reducing the diameter of the cutter which
remains the same notwithstanding many repeated sharpening operations. This is
au important feature of the construction shewn, avoiding an objection to many
cutters formed with longitudinal parallel teeth rounded off at their ends, for in
these the cutting is effected by the edges of the teeth, which are parallel to the
axis and consequently, in sharpening these, the diameter of the cutter is somewhat
reduced.
The shank 3 besides the cutter head receives also a guide 15 which enters the
hole to be enlarged and centres the cutter therein. On the stem 4 is screwed a nut 16
by which the guide and cutter are fixed on the mandrel and in engagement with the
collar 2.
The reamer described is particularly designed for finishing the brass boxes for
shafting after the sand has been removed from the castings, the holes in the castings
being made to fit the guide 15. The improved cutter will enlarge holes without
corrugating the surfaces of the bores, as is often done by reamers now in use.
In the modification shewn by Figs. 6 and 7, the form of the cutter-body is the
same as described above, but the cutter-teeth 17 are adjustable in a plane parallel
with the axis of the mandrel, so that when the straight cutting-edges 10 and bevel
faces 9 become unduly worn by regrinding, the teeth can be adjusted lengthwise in
a plane parallel with the axis of the mandrel to compensate for the wear.
Το
effect this adjustment, each cutter-tooth 17 is provided with a longitudinal slot 18
through which passes a set screw 19 into the face 8 of the cutter-body. The acting
extremities of the teeth are formed with bevelled portions 20, coinciding with the
bevelled faces 9 of the body so that the cutter can be sharpened by grinding in the
manner above described and indicated in Fig. 5.
The construction of the cutter is such that by giving the teeth the requisite
rake it can be used for cutting any material, including wood.
The cutter is made removable and replaceable for the purpose of enabling any
one of a series of cutters to be used on the mandrel for the purpose of cutting
holes of different diameters, while permitting a cutter, if broken, to be promptly
replaced at a small expense. A reamer such as I have described, though

page_text: particularly useful for boring boxes of shafting can be employed for boring other
articles including ordnance. By the adjustments shown in Figs. 6 and 7 it can be
suited for boring holes of various diameters.
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:
1-A reamer comprising a manifold toothed cutter having each tooth formed
with a rectilinear face 8 in the plane of the axis, and a bevelled front end 9
running backward at an acute angle to the face to form a straight radial cutting-
edge 10 at right angles to the longitudinal axis so that the teeth can be ground by
an ordinary grindstone without in any way reducing the diameter of the cutter,.
substantially as described.
2-A reamer consisting of a mandril 1 having a collar 2 provided with recesses 5,.
a cylindrical shank 3 with a screw stem 4, a manifold toothed cutter provided with
shoulders 6 to engage the recesses 5, and having each tooth formed with a straight.
face 8 in the plane of the axis of the mandril, and a bevelled front end 9, running
backward at an acute angle to the face to form a straight radial cutting edge 10 at
right angles to the longitudinal axis, a cylindrical guide 15 and a screw-nut 16 sub-
stantially as and for the purposes set forth.
3-A reamer comprising a removable and replaceable manifold toothed cutter
having each tooth formed with a straight face 8 in the plane of the axis of the
reamer, and a bevelled front end 9 running backward at an acute angle to the face
to form a straight radial cutting-edge 10 at right angles to the axis of the reamer,
and having shoulders 13 to guide a grindstone in grinding the bevelled front ends of
the teeth substantially as described.
Dated this 16th day of March 1892
ABEL & IMRAY,
Agents for the Applicant..