IMPROVEMENTS IN MACHINERY FOR DRESSING MILLSTONES BY MEANS OF A DIAMOND CUTTER
Year: 1862

page_text: LETTERS PATENT to John Adams Knight, of No. 4, Symond's Inn,
Chancery Lane, in the County of Middlesex, Patent Agent, for the
Invention of "IMPROVEMENTS IN MACHINERY FOR DRESSING MILLSTONES
BY MEANS OF A DIAMOND CUTTER."-A communication from abroad by
John Dickinson, of New York, United States of America.
Sealed the 24th June 1862, and dated the 16th January 1862.
PROVISIONAL SPECIFICATION left by the said John Adams Knight
at the Office of the Commissioners of Patents, with his Petition, on the
16th January 1862.
I, JOHN ADAMS KNIGHT, of No. 4, Symond's Inn, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN MACHINERY FOR DRESSING MILLSTONES BY
MEANS OF A DIAMOND CUTTER," to be as follows:-
My Invention relates chiefly to a self-adjusting holder or stock, in the lower
end of which is secured the "cutter," and to a graduated parallel motion
guide rule for guiding the cutter across the face of the stone, and also to a
novel arrangement and combination of the different parts.
By the use of my Invention a more uniform and perfect surface is produced.

page_text: than by the use of a "pick hammer" generally used for dressing mill-
stones.*
The self-adjusting holder or stock is placed in a box or frame with a slot or
channel on one side which permits the holder to move up and down freely. To
prevent the diamond from passing below the under surface of the frame so as
enter the cavities, if any, in the face of the stone, a ledge is formed on the side
of the stock or holder, and a corresponding ledge is formed on the lower part
of the frame inside. For the purpose of giving the "cutter" an elastic and
constant pressure upon the face of stone, a spring is placed at the top of
the stock or holder, and the tension is regulated by a set screw or other similar
device. To the side of said frame is attached an adjustable guage for the
purpose of securing the frame securely upon the slide ways of the parallel rule
so as to give the "diamond cutter" a uniform line across the face of the
stone; these parallel slide ways are attached to a bed board by means of
jointed arms, and are operated by means of a lever working on a centre pin
fixed in the bed board and connected at the longest end with the slide ways.
On the short end of this lever is formed or attached a quadrated cog gear into
which quarter sections of bevelling cog teeth match. The two sections are
formed upon opposite sides of a vertical wheel rotating on a bearing fixed to
the bed plate or board.
The object of this arrangement of the cog teeth in quarter sections, with
intermediate spaces is to permit the slide ways to distend after being closed,
which distension is produced by a spring attached to the bed plate acting
against the lever which operates the slide ways. For the purpose of securing
uniform spaces between the lines another wheel is fixed on the axis, having on
its periphery a series of notches cut to correspond with the number of lines to
be made. As the motion of the slides is not uniform these notches are cut
with unequal spaces between them, so that the pawl which is secured to the
axle bearing by a centre pin as it falls into the successive notches will indicate
an equal and uniform succession of lines to be drawn across the face of the
stone in any given space.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Adams Knight in the Great Seal Patent Office on the
15th July 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
ADAMS KNIGHT, of No. 4, Symond's Inn, Chancery Lane, in the County of
Middlesex, Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of January, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-fifth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said John Adams Knight, Her special licence that I, the said John Adams
Knight, my executors, administrators, and assigns, or such others as I, the
said John Adams Knight, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain and
Ireland, the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN MACHINERY FOR DRESSING MILLSTONES BY MEANS OF A DIAMOND CUTTER," (a
communication to me from abroad by John Dickinson, of New York, United
States of America,) upon the condition (amongst others) that I, the
said John Adams Knight, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention, and in
what manner the same was to be performed, and cause the same to be filed
in the Great Seal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Adams Knight, do hereby
declare the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement thereof:-
The nature of my Invention consists in the novel construction and arrange-
ment of the different parts of a machine for dressing millstones, especially
designed for use in connection with a "diamond cutter."
Among these parts are a double guide-way parallel rule, with the means of
operating the same; a diamond cutting instrument, with the means of
guiding, operating, and steadying said instrument; two adjustable steel shields
secured in a channel formed in the lower surface of the parallel rule to

page_text: protect the setting of the diamond; two raised ledges of metal secured to the
under surface of the double guide-way, forming a channel for the parallel rule
to rest upon; and a self-adjusting diamond protector.
But I will now proceed to particularly describe and ascertain the nature of
said Invention and in what manner the same may be performed, reference
being had to the accompanying Drawings which form a part of this Specifi
cation, the same letters marked thereon indicating like parts wherever they
occur.
Figure I. is a plan view of the mechanism; Figure II. is a lower side view
of the double guide-way; Figure III. is a detached view of the scroll cam
wheel; Figure IV. is an end view of the double guide rule, showing the
ledges forming the channel in its lower face and the ledge on its upper side;
Figure V. is a transverse cut section of the double guide rule, showing the
diamond protector instrument adjusted upon it; Figure VI. is a vertical cut
section of the diamond protector through the line cc, x, Figure V.
Letter A is the frame or bed board of the apparatus, forming the back half
of the parallel rule. To its front edge is secured a double guide-way or
rule d by means of two cross extension arms C and D. The arm C is
secured at its ends by centre pins E to the right and left hand corners of the
bed and rule, whilst the arm D has only one end fixed as a centre of motion,
the opposite end having a slot G in it so as to permit it to have a compen-
sating motion on its centre pin H to keep the
moves out or back by means of the cam wheel.
rule in a vertical line as it
This is obtained by means of
into or against the sides of
a scroll cam wheel I secured on a centre pin J,
the cam groove a stud K on an arm L works. This arm projects from the
back side of the arm C at its point of intersection with the compensating
arm D, and is held in connection with it by a pin M working through a slot N
in the arm D, so that as the scroll is developed by the rotation of the cam
wheel, the arm C is shortened or lengthened (as the case may be) whilst the
arm D increases or diminishes in length by slipping on the pins H and M
to compensate the irregular motion of the parallel rule. To operate the scroll
cam wheel teeth are cut on its periphery, into which engage two pawls P
and Q. The pawl P is secured by a pin R to a propelling lever U, and the
pawl Q by a pin S to the standard T. The lever U is somewhat like a ball
crank, having its centre of motion on the cam wheel centre pin J, so that
when the arm U2 of the crank is operated by the attendant, the pawl P on the
other arm U will propel or rotate the cam wheel, and by means of the tension
spring Z (shown in red outline, Figure I.) connecting the two pawls together

page_text: hold the parallel rule firmly at the place required to make the cut with the
diamond. Letter V. is a reacting spring secured on the head of the cam wheel
centre pin J, and in a barrel W on the upper side of the cam wheel cap
plate (indicated by the red outline, Figure I.) The object of this spring is to
readjust the rule instantly on releasing the pawls from the teeth on the edge:
of the cam wheel. Letter a² is a graduated scale of degrees upon a fixed.
portion of the frame or bed of the machine, and 63 is an adjustable stop,
and a binding screw to hold it. The object of this scale is to graduate;
the number of lines per inch, to be made by. the rule, and thus obviate
measurements at each time of using the apparatus. Letter d² is a double
guide way or rule. Upon the upper side of the inner guide arm is a raised
ledge. The object of this ledge is to form a bearing against which the
diamond stock is steadied when being drawn across the face of the millstone.
Letters f, f, are two thin strips of hardened steel or other 'metál running
lengthways of the double guide way in a channel formed on its under side by
means of two raised ledges 92, 93, on each arm of the double guide way.
These strips of metal are secured to the ends of the double guide way by
clamps h² and binding screws k², at about a quarter of an inch apart, and their
use is to shield the setting of the diamond from coming directly in contact
with the face of the millstone, and the use of the ledge g² is to form a pro-
tection to the thin strips of metal forming the shields from being twisted or
warped by dragging upon the face of the millstone in the backward and
forward movements of the rule, as would be the case if there were no protection
ledges and they were permitted to rest directly on the millstone. Letter m²
is a diamond protector which is made in the shape of a knob or handle of an
ordinary cutting tool. In the lower end of it is a vertical square slot ², in
which is arranged a square block p³, having a diamond p³ secured in its lower
end. In the side of the block is cut a niche q into which engages a pin 2,
inserted in the side of the slot n³. The object of this is to prevent the diamond
from projecting below the face of the handle m³, and thus getting into any
cavities in the face of the millstone. To keep the diamond down upon the
face of the millstone a spindle s² is inserted through the middle of the handle,
having its lower end resting on the head of the diamond block, and upon its
upper end a spiral tension spring 2 which is confined in the cavity of the
handle by a screw v2, so that by means of the compression of the spiral spring
by the action of the the screw, the diamond will be kept with a sufficient
amount of elastic pressure on the face of the millstone to give the
required cut without any application of pressure by the operator other

page_text: than is required to hold the instrument firmly in the double guide way.
Letter is an adjustable guage secured to the sides of the diamond
protector by means of a binding screw y². The object of this is to guage
the adjustment of the instrument in the double guide way so that it can
always be drawn with an even and uniform pressure across the face of the
millstone.
Having fully ascertained the nature of my improvements, I wish it
understood that I do not confine myself to the exact details described, but
I claim the said Invention substantially as and for the purpose herein set
forth.
In witness whereof, I, the said John Adams Knight, have hereunto
set my hand and affixed my seal, this Seventeenth day of June,
in the year of our Lord One thousand eight hundred and sixty-
two.
JOHN ADAMS KNIGHT. (L.S.)