IMPROVE- MENTS IN MACHINES FOR CUTTING THE TEETH OF FILES AND RASPS AND SIMILAR ARTICLES
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by John McGregor at the Office of the
Commissioners of Patents on the 14th February 1880.
" IMPROVE-
MENTS IN MACHINES FOR CUTTING THE TEETH OF FILES AND RASPS AND SIMILAR
ARTICLES."
JOHN MCGREGOR, of Sheffield, in the County of York, Engineer.
My Invention consists in the first place in a method of varying the extent of
lift given to the ram or hammer to which the cutting chisel is fixed, so that the
force of the blow given can be easily regulated according to the depth or width of
the cut required.
For this purpose the revolving shaft, on which is fixed the cam for lifting the
hammer, works in a bearing, which is movable, and the position of which can be
changed according to the force or strength of the blow required.
My Invention consists in the second place in a mode of causing the bed on which
the file rests to oscillate in such a manner that files which require the rows of
teeth to be cut obliquely to each other (as in the backs of half round files) can be
readily brought to the position required, and the rotary motion of round files on
the cutting bed required for the necessary number of rows can be made auto-
matically with the greatest accuracy. For this purpose there are applied at the
front of the oscillating bed on which the file is placed a worm wheel and pinion,
which worm wheel is connected to the bed by a key and corresponding groove in
the bed, and the attendant by turning the wheel (which is placed conveniently)
can make the rows of the file in the required position. My Invention consists in
the third place in a method of varying the angle of the cutting chisel and presser
to suit the angle of the over and up cut, and any intermediate angle that may be
required.
For this purpose I fasten the ram or hammer to the slide or ways on which it
works by means of a screw and nuts, which can be loosened, and the chisel set to
the desired angle and the screw fastened again, and the presser is connected to the
ram or hammer, so that it turns on the same centre, and can be readily made to
correspond with the angle of chisel.
My Invention consists in the fourth place in a ready method of taking out and
replacing the cutting chisel, so that it can be sharpened or whetted with a minimum
stonnage of the machine.

page_text: For this purpose there is placed in front of the chisel a shaft, on which is fixed
an excentric or cam opposite the chisel, and at each end of this shaft there is a
handle, by which the attendant can turn the shaft. When the chisel is fast to the
hammer it is kept in position by the pressure of the cam, and when it is required
to be taken out the cam can be withdrawn from the chisel by turning the handle
through a portion of a circle, and allow the chisel to be removed and replaced with
the greatest dispatch.
And my Invention consists in the last place in an arrangement of machinery by
which a whetstone is driven by the same motive power as the machine, and placed
in such a position that the attendant can quickly whet or sharpen the cutting
chisel and replace it without removal from the position required to work the
machine.
From the same shaft which drives the cutting machine power is communicatod
to a pulley, in which is formed a slot from the centre to the periphery. In this
slot is placed a stud, which can be shifted to any required distance from the centre
of the pulley. To this stud is fixed an upright lever, and from this lever a rod is
connected with whetstone, and as the pulley revolves a reciprocating motion is
thereby given to the whetstone, according to the distance from the centre at which
the stud is placed.