IMPROVEMENTS IN PORTABLE LATHES, CHIEFLY INTENDED FOR THE USE OF DENTISTS AND JEWELLERS
Year: 1875

page_text: LETTERS PATENT to William McIntyre Cranston, of No. 36, Worship
Street, Finsbury, in the County of Middlesex, for the Invention of
"IMPROVEMENTS IN PORTABLE LATHES, CHIEFLY INTENDED FOR THE USE OF
DENTISTS AND JEWELLERS."-A communication from abroad by
Franklin Scott, of Bennington, State of Vermont, in the United
States of America.
Sealed the 21st August 1875, and dated the 24th February 1875.
PROVISIONAL SPECIFICATION left by the said William M'Intyre
Cranston at the Office of the Commissioners of Patents, with his
Petition, on the 24th February 1875.
I, WILLIAM MINTYRE CRANSTON, of No. 36, Worship Street,
Finsbury, in the County of Middlesex, do hereby declare the nature of.
the said Invention for "IMPROVEMENTS IN PORTABLE LATHES, CHIEFLY INTENDED
FOB THE USE OF Dentists and JewELLERS,” to be as follows:-
This Invention relates to special details of construction in portable
lathes, chiefly intended for use by dentists, jewellers, and others by whom
delicate manipulations are performed, ..

page_text: The lathe forming the subject of this Invention is composed of a
vertical standard upon tripod feet, in which standard an adjustable stem
is fitted, this carrying at its upper part a kind of table or head, also
adjustable, in the under part of which radial spindles can be driven from
an underneath motion worked by treadle or by hand, as desired. The
radial spindles carry each chuck plates or other appliances, in or by
which tools of various kinds or grinding or polishing wheels can be fitted
for operating upon the articles that may be necessary. The stem also
carries an adjustable bracket, in a socket of which a rest or bearing plate
is arranged, which rest is adjustable both vertically and horizontally,
and capable of being set in any position by thumbscrews. The table or
head can be turned upon the stem to bring any one of the tools or
appliances round to the rest, and it can be locked in that position by a
cramp. By this means one man by simply turning the head or table
round to his rest can cause an operation, successively or not, of the
various tools; or a number of men can set round the lathe and manipulate
the various objects or articles, or perform the different workings put
under their charge.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William MºIntyre Cranston in the Great Seal 2
Patent Office on the 24th August 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
M'INTYRE CRANSTON, of No. 36, Worship Street, Finsbury, in the
County of Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters 2
Patent, bearing date the Twenty-fourth day of February, in the year of
our Lord One thousand eight hundred and seventy-five, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said William M°Intyre Cranston, Her special
licence, that I, the said William McIntyre Cranston, my executors, ad- 3
ministrators, and assigns, or such others as I, the said William M°Intyre
Oranston, my executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times there-
after during the term therein expressed, should and lawfully might

page_text: 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 PORTABLE LATHES, CHIEFLY INTENDED FOR THE USE OF
DENTISTS AND JEWELLERS," (communicated to me from abroad by Franklin
Scott, of Bennington, State of Vermont, in the United States of America,
upon the condition (amongst others) that I, the said William M'Intyre
Cranston, 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
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William McIntyre Cranston, do
hereby declare the nature of my 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, that is to say :—
This Invention relates to special details of construction in portable
lathes, chiefly intended for use by dentists, jewellers, and others by whom
delicate manipulations are performed.
The lathe forming the subject of this Invention is composed of a
vertical standard upon tripod feet, in which standard an adjustable stem
is fitted, this carrying at its upper part a kind of table or head, also
adjustable, in the under part of which radial spindles can be driven from
an underneath motion worked by treadle or by hand, as desired. The
radial spindles carry each chuck plates or other appliances, in or by
which tools of various kinds or grinding or polishing wheels can be fitted
for operating upon the articles that may be necessary. The stem also
carries an adjustable bracket, in a socket of which a rest or bearing plate
is arranged, which rest is adjustable both vertically and horizontally,
and capable of being set in any position by thumbscrews. The table or
head can be turned upon the stem to bring any one of the tools or
appliances round to the rest, and it can be locked in that position by a
cramp. By this means one man by simply turning the head or table
round to his rest can cause an operation, successively or not, of the
various tools.
In the annexed Drawings like letters refer to corresponding parts in

page_text: Figure 1 of the Drawing exhibits a front elevation of this lathe with
portions thereof broken away, so as to exhibit in vertical cross section the
construction of several parts of the machine.
Figure 2 shows a plan of the top of the lathe, with a portion thereof
broken away to exhibit one of the spindles, its construction, and
attachments.
Figure 3 shows an elevation of the right side of the lathe with portion
of the standard seen in cross section, showing the construction and
mode of adjustment of the box through which the main driving shaft
works.
This lathe is constructed with a tripod x supporting a hollow column B.
To this column the pinion S operated by a crank is attached. This
pinion meshes into and actuates a rack upon that part of the standard A
within the column B. By means of this rack and pinion the standard A
and its several attachments are elevated or depressed. By the use
of the set screw y the standard is firmly secured in place after ad-
justment. To the upper part of the column B and turning upon a
shoulder constructed thereon to receive the same is adjusted the sleeve
or collar C having a projecting arm C¹ supporting a tubular socket D, in
which socket the vertical standard I¹ is fitted, provided with a rotating
socket arm M at its upper end, the hub of which arm is pivotted upon
and rotates about said standard. The outer extremity of the arm M has
a tubular socket to receive and hold the stem K of the table N. The two
sockets last described are each provided with set screws, by which the
standards I and K are respectively fastened and adjusted.
The table N is constructed with slots, as shown in Figure 2, by the
use of which any tool, piece of work, or article may be securely fastened
thereto, as may be found desirable when in use. It is obvious by an
analysis of this mechanism that any tool used upon or in connection
with the table N may be adjusted in any position with reference to the
piece of work attached to either of the spindles herein-after described, or
vice versa.
The column A is constructed with an open slot or chamber Q which
receives the adjustable box e, e, in which revolves the shaft c when it is
deemed desirable to rotate the shaft. The box e, e, is vertically
adjustable, and its adjustment is secured by tightening the set screw u,
Figure 3.

page_text: I have shown in the Drawings a shaft c, to one end of which the small
pulley is attached, by using which the machine may be operated by
other than foot power. The lateral or rather longitudinal adjustment
of the shaft is provided for by two collars and set screws t, t. To the
opposite end of the shaft is attached either a friction pulley gear or
common grooved pulley, as either may be found. desirable or best
adapted to the particular work in hand. Upon the face of the wheel E
is constructed a crank rim to which the wrist pin c¹ is attached, and this
is connected with the treadle O by the adjustable compound pitman
composed of a male portion I and female portion H. When adjusted
the two parts I and H are secured by tightening the set screw v,
Figure 3, provided for that purpose. When other than foot power is
used this pitman can be detached, and the machine driven by the
pulley f. The object of the vertical slot or chamber Q is to make room
for the vertical adjustment of the box e, e. When it is found desirable to
use driving wheels, pulleys, or gears of variable diameters in connection
with the spindles operated thereby that part of the standard A shown
at b. is threaded for a short distance to receive the nut J. Upon this
nut and about the upper part of the standard A rotates the head or
stock F.
The leading features of this Invention are shown in the various
devices connected with this rotary head, their several adjustments and
uses, as well as in the labour saving features, and general utility of the
head itself. The head F consists of a hub K disc A¹ perforated beneath
each spindle, so as to allow contact with the driving wheel gear or
pulley, as the case may be, and the rim or periphery thereof F, which
rim is cut away at those points where the boxes are inserted, in which
the several spindles run. The hub of this head is constructed with as
many sides or facets upon or about that portion thereof which projects
above the upper side of the disc A¹ as there are spindles, and is so made
that one-half of the box or bearing of the inner end of the spindle is
formed in each of these facets, as seen in Figure 1. The cap &¹ forms
the other half of this box. The outer box is made by slotting down
from the upper edge of the rim to a depth sufficient to receive the box,
and inserting in such slot a box made in halves, as seen at a,. Figure 1,
and provided with flanges to prevent its displacement therefrom. Over
this box is placed a cap s¹, so fitted as to fill between the flanges of the
box and preserve the continuity of the upper edge of the rim of the head,

page_text: as seen at 8, Figure 2. The spindles designed to run in these boxes each
provided with a friction pulley W, a spur or spiral gear Y, and a pulley
to be run with a belt Z, as shown.
Of course it is impracticable to use at once more than one of these
devices for communicating motion or power, but it is frequently the case
that the mode of driving best adapted to one class of work proves
unsuitable for another, and I have constructed this machine so that
driving wheels, gears, or pullies of different diameters may be used, and
if desired the friction wheel E' shown may be removed, and a driving
gear with a shorter hub may be substituted, revolving in another plane,
so as to work or run in conjunction with the small pinion Y on the
spindle. Either of these drivers may be constructed to revolve upon or
with the shaft, as may be deemed practicable. The outer ends of these
several spindles are constructed so as to admit of the application of a
great variety of implements for executing a wide range of work, such,
for instance, as chucks, face plates, emery wheels, burrs, mandrils,
centers, &c.
In the Drawing I have showed at m an emery wheel, at 9 a socket or
stock for the introduction of drills and other like tools, at a spindle to
receive a chuck, at 9 a tapering screw to receive buffers, brushes, &c.,
at n two lathe centres, and at p a device for transmitting motion
universally. This last device has been found particularly useful to
dentists in transmitting motion to drills, &c., for operating upon natural
teeth. It is here introduced and combined especially for such uses.
These machines may be constructed with as few or many spindles as a
may be desired.
Above the chamber Q before described, and beneath the nut J, an
arm T is attached to the standard A, projecting upwardly and provided
with a pin U; the lower projecting portion of the hub K is perforated
with holes to correspond with the number of spindles arranged on or a
about the head, and their position when in adjustment in reference to
the driving wheel. These holes g', Figure 3, receive the pin U, and by
this device the head is securely held in adjustment when in use. By
withdrawing the pin U the head is left free to be rotated, so as to bring
into position and consequently into action the spindle wanted. The a
vertical adjustment of the head F upon its axis on on the standard A. is
accomplished by means of the flange or disc w, which is provided with a

page_text: chamber Q, box e, e, shaft c, so constructed as to receive and operate a
driving pulley gear or friction wheel, the arm T, pin U, and holes g¹
for locking the head when adjusted, the thread d, nut J, disc w, stem b,
and recess in end of standard A, into which said stem screws, for the
purpose of making vertical adjustments of the head F, the spindles X
provided with the friction pinion W, gear Y, and pulley Z, for the
purpose of obtaining different applications of power, the pitman com-
posed of the two parts I and H in connection with the treadle O, thus
constructed to be adaptable to the variable vertical adjustments of the
driving wheel E, and the plain top or cover G attached to the disc
plate w adapted to hold or receive either tools or work, all arranged and
operating as described.
Secondly. The method of bringing into action successively without
distributing any of the adjustments of the other parts of the machine of
the several spindles and their attachments by arranging said spindles
radially in, upon, or about a head or stock F, so that when said head is
rotated about its axis each spindle so arranged thereon will or may have
the pulley gear or friction force brought into co-operation or conjunction
with a driver common to them all, and running upon a stud or shaft
attached to the standard about which the head aforesaid revolves, all as
shown and described.
Thirdly. The method shown of elevating or depressing the axis of the
driver E, to wit, the shaft or stud c, so as to enable drivers of different
diameters to be used in conjunction with the several spindles, and which
is accomplished by the slotted chamber Q, movable box e, e, and set
screw u, substantially as shown and described.
Fourthly. The universal rest table N, having capacity for adjustment
in all desired positions, accomplished by the mechanism consisting of the
collar C and C¹, tubular socket D, socket arm M, stem k, and set
screws j, i, and L, as set forth.
Fifthly. The means shown of communicating motion universally to
independent tools, implements, or mechanism, and consisting of the
tripod x, column B, standard A, shaft c, driving wheel E, rotary head F,
spindle X, and its attachments and device p, all arranged and operating
as shown.
Sixthly. The method shown of adjusting the head F by means of a
thread cup upon the standard, about which the head revolves and a nut

page_text: working thereon, in conjunction with a flange or disc attached to the
under side of the cup or table covering the whole top of the machine,
and having a threaded stem to screw into or over the end of the standard,
all constructed to bear against opposite sides of the hub of the head, as
described.
Seventhly. In combination with the rotary head F provided with
radial spindles as aforesaid the means of locking or fastening said head
in position when adjusted, and consisting of the arm T, pin U, holes g¹,
and standard H, operating as described.
In witness whereof, I, the said William M°Intyre Cranston, have
hereunto set my hand, this Twenty-fourth day of August, One
thousand eight hundred and seventy-five.