IM- PROVEMENTS IN THE MEANS EMPLOYED FOR TURNING AND SHAPING POTTERS' CLAY
Year: 1875

page_text: LETTERS PATENT to James Murdoch Napier, of York Road,
.
Lambeth, in the County of Surrey, for the Invention of "IM-
PROVEMENTS IN THE MEANS EMPLOYED FOR TURNING AND SHAPING POTTERS'
CLAY"
PROVISIONAL SPECIFICATION left by the said James Murdoch
Napier at the Office of the Commissioners of Patents, with his
Petition, on the 10th May 1875.
I, JAMES MURDOCH NAPIER, of York Road, Lambeth, in the
County of Surrey, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE MEANS EMPLOYED FOR TURNING AND SHAPING
POTTERS' CLAY," to be as follows:-
. This Invention relates to improvements in the means employed for
turning and shaping potters' clay. I form the cutting or shaving part of
potters' clay turning and shaping tools of metal plate so thin as to serve
as a sufficient cutting edge without being bevelled off or sharpened, and
at the same time strong enough to support the force operating against it

page_text: while cutting. These tools are accurately formed to produce the shapes
required, and they are presented to the work with mechanical precision
by means of a slide rest or analogous mechanism. In practice I have
found rolled tempered steel answer well.
I attach the thin plate of metal, which I will call the "edge plate,"
to a holder, so that it is fast to and supported by the holder while the
portion to be used for cutting projects and retains its cutting power
owing to its thinness until it is worn away. The extent which the
' edge plate "should be allowed to project beyond its support will
depend upon its strength or rigidity and the work and wear which it is
intended to bear.
<<
I shape the "edge plates" according to the form of the part of the
vessel or article upon which they are to operate.
I also shape the holders suitably to support the edge plates according
to their shape.
S
"
I sometimes attach several "edge plates" to one holder, so that they
may assist together to shape the vessel or article, and when the form to
be shaped permits; I sometimes arrange "edge plates on one or more
holders to operate upon the outside and inside of the vessel or article
at the same time.
When an "edge plate" is sufficiently worn it may be reshaped and
reset in the holder.
In certain cases where large quantities of similar articles or vessels
are required to be turned or shaped I replace the "edge plates" with
new ones as soon as they are worn unfit to serve longer, and I employ
means such as cutters, punches, and dies, by the aid of which with
rapidity and economy I prepare new "edge plates," each exactly similar
in form according to the desired pattern, so that they can with great
facility be fixed accurately in the places prepared for them in the
holders.
I sometimes employ my tools as roughing tools, in which case worn
tools may be used. The roughing out of the clay vessel or article with
roughing tools reduces the wear on the finishing tools so that they will
last longer.

page_text: lathe, or otherwise, according to the kind of machine or apparatus in or
by which the clay vessels or articles are to be operated upon.¨
I prepare and arrange suitable stops, fixings, and adjustments, so
that the tools can be removed from their places in the machines in
which they are used, and so that they can be replaced with ease and
accuracy.
I sometimes, when the forms of the clay vessels or articles admit
hold them for being operated upon by means of expanding mandrils
and contracting chucks composed of a number of wedge plates or
slides which are caused to contract and expand by inclined planes.,
In some cases the simple pressure of the band upon the vessel or
article fixes it enough upon or within the wedge plates, as the case may
be; in other cases I employ a spring.
In the process of turning or shaping some vessels or articles I use a
sight gauge or index carried by or with the tool to determine the thick-
ness of clay at the end of the vessel or article and its length.
In the turning or shaping of a vessel or article several of my tools
may be used in succession or together, and the ordinary hand tool may
also be used to assist in the completion of the work.
To enable me accurately to set the edge plates in their holders I
sometimes employ gauges representing an outline of the form of the
vessel or article to be turned or shaped. These gauges I fix on plates
provided with stops or adjustments, so that the tool or edge plate
holder can be set in position in respect to the gauges, while these
last serve to guide the placing and fixing of the edge plates to the
holder.
When my improved tools are to be used in the slide rest of a lathe,
I prefer to reverse the tool so that the "edge plate" is downwards or on
the under side of the holder, and the cut is made by it in that position
on the far or rising side of the lathe so that the cuttings may fall
away clear and not rest on the tool, and I arrange the lathe and slide
rest accordingly. By this arrangement also the front of the lathe is
free for a hand rest.
It will be understood that my Invention is applicable to moving
or revolving tools as well as to fixed tools.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Murdoch Napier in the Great Seal Patent
Office on the 10th November 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
MURDOCH NAPIER, of York Road, Lambeth, in the County of Surrey,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Tenth day of May, 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 James Murdoch Napier, Her special license
that I, the said James Murdoch Napier, my executors, administrators,
and assigns, or such others as I, the said James Murdoch Napier, 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 THE MEANS EMPLOYED FOR TURNING AND SHAPING POTTERS'
CLAY," upon the condition (amongst others) that I, the said James
Murdoch Napier, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should par-
ticularly 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 James Murdoch Napier, 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, that is to say:-
-
This Invention relates to improvements in the means employed for
turning and shaping potters' clay. I form the cutting or shaving part
of potters' clay turning and shaping tools of metal plate so thin as to
serve as a sufficient cutting edge without being bevelled off or

page_text: slide rest accordingly. By this arrangement also the front of the lathe
is free for a hand rest.
It will be understood that my Invention is applicable to moving or
revolving tools as well as to fixed tools.
DESCRIPTION OF THE DRAWINGS.
In Figure 1 A represents a clay vessel held in an ordinary dog
chuck B with screws and sliding blocks. Chuck B is fastened to C,
which represents the mandril of a lathe by a bayonet joint to ensure
ready replacing and removal. D is the tool holder furnished with edge
plates a, a, a². The tool holder is seen reversed, and having the edge
plates fixed on the under side; they are shewn dotted.. Edge plate a
is formed to shape the outside of the vessel; a', the end; and a the
inside.
In consequence of the position of the tool on the far side of the lathe,
and supposing that the lathe is rotated in the usual direction, it will be
seen that the cuttings will fall clear. The tool is supposed to be
fastened to a slide rest by its end D', and it is shewn in the position
fully outwards, and having finished its work is ready to be withdrawn.
Figure 2 shews the vessel A placed on an expanding mandril, which
is further illustrated by Figures 3, 4, and 5. In this mandril E is the
body are eight sliding wedges attached to plate F by screws, which
are firm in the wedges, but free in the plate F, the holes in the plate F,
through which the screws pass, being elongated, so that as the wedges
occupy the outward or inward position shewn in Figures 3 and 4 the
screws rise or fall freely in the elongated holes in the plate F.
It will be seen that in Figure 4 the mandril is expanded to its full
size, while in Figure 3 it is contracted to its smallest size.
The spring c may be used to keep the wedges & sufficiently tight up
to their work of holding the vessel, but at the angle which the wedges
or inclined planes 6 are shown. The spring may not be necessary, or if
used it should not force the clay too much.
In practice I have found that a slight pressure will fix the vessel on
the wedges when the angle of incline is as shewn, but when a greater
angle is used a spring will become necessary.

page_text: The expanding mandril is shown with shank to fix to a lathe mandril
by bayonet joint, but it may be otherwise fixed to the lathe mandril if
preferred.
When the vessel A is pressed on to and fastened to the mandril E, as
seen in Figure 2, the tool D2 (the edge plates attached to which are
formed to shape the bottom of the vessel) is brought up to its work by
a slide rest, in which it should be fixed, and it is now shewn as having
completed the shaping of the bottom and base of the vessel A, the front
of the sight gauge or index d having arrived in a position so that it lines
even with the line e of the base of the vessel which was formed by the
previous tool D. In this manner it will be seen that the desired
thickness of the bottom of the vessel can be secured.
Figures 6 and 7 shew respectively clevation and plan of tool D₂ held
in G, which represents the top slide of a slide rest. The stops f‚ƒ¹‚ƒ³,
are provided and fixed with accuracy to the slide rest, so that when the
tool D² or tool D of Figure 1, or other tools suitably formed, are brought
against them, as in Figure 7, the tools will be in the exact position for
use to accomplish the shaping of the vessel or article which it may be
desired to shape.
In Figure 6 the edge plates are shewn fastened to holder D by a
screws g, g, and binding plates h. Figures 8 and 9 shew the finished
vessel in elevation and section.
Figures 10 and 11 represent a contracting chuck H fastened by screws
i, i, i, i, to the plate I¹ on the end of the lathe mandril I. The lathe
bearings in which the mandril is supported are represented at J, J. It
will be seen that chuck H is furnished with eight inclined planes or
wedges mounted in grooves in H, so that when they are pulled
inwards they will close upon and hold an article of suitable diameter
and shape placed within them. Plate / performs a similar office in this
case to that performed by plate F, as already described with reference to
Figures 3, 4, and 5, and is connected to the wedges j by screws / in the
same way. A¹ is a rod fixed to plate %, and which passes along through
the mandril I, which is hollow, and terminates in a screw, on which is
fastened the nut button k³. The spring 4* abuts against the end of the
mandril I and acts against the button ³, and thus through the rod;
¹ and plate k, and screws 7 tends to pull in the wedges j towards the
mandril face, but for illustration the wedges are shewn in their outward

page_text: position, and the spring is supposed to be under compression, as if the
button was being pressed by the hand to release an article which has
been held in the chuck or to open the chuck to receive an article.
The arrangement just described of passing a rod through the mandril
of the lathe for opening and closing the chuck H may also be applied to
the expanding mandril previously herein described, in which case the
rod would pass through the mandril E and be attached to the plate F..
The ring, with fastening screw k³, serve to keep the mandril in.
position while the spring is compressed by pressure on the button k³..
Figure 12 represents a template block or plate K to be used for
accurately setting the edge plates in their holder. L is a gauge or
template representing that part of the form of the vessel to which the
edge plates of tool holder D are to be adjusted. Tool holder D is
provided with two holes m, m, which fit accurately on pins fast in
plate K. When placed on these pins the tool holder is in its exact
requisite position in relation to the template or gauge L, so that the
edge plates may be brought up against it and then fastened to their
places by the screws g and the binding plates h. When the edge plates
are cut out to shape and exact form by means of punches and dies, as
already referred to, and are intended only to serve until they are worn
and are not to be reshaped, I punch in them small holes n, such as are
seen in Figures 1, 2, and 7, in exact position, so that they fit on to pins
which are fixed in the tool holder, and which pass up through the
binding plate which by the screws fixes the edge plate in its place.
pins referred to are placed in the tool holder with exactness as to
position, so that when the edge plate is put upon them it is exactly set
for cutting or shaping the article to the diameter and form desired.
The
This latter mode of setting the edge plates in position on the tool
holder is further indicated in Figure 13, the under side of the tool
holder D being here shown, on which are placed the edge plates by
means of the guide pins which pass into the holes n in the edge plates
and the binding plates h, through which also the guide pins pass. The
fixing screws pass through both binding plates and edge plates, fitting
freely, and screw into the tool holder so as to fasten the binding plates
and edge plates firmly to the tool holder.
Instead of punching holes in the edge plates as guides and setting
them on pins in the tool holders, the tool holders may be furnished with

page_text: pins or stops, against which the non-cutting edges of the edge plates
may be set in order to place the edge plates in their right positions on
the tool holder.
Figures 14 and 15 illustrate modes in which an article M having a
certain figure may be treated. In Figure 14 N represents an edge plate,
which may be supposed to be held in a tool holder and applied to the
article by means of a slide rest in the direction of the arrow so as to
complete the formation, except in respect of the part at the end where it
would be held while being shaped. In Figure 15 O and P represent two
edge plates which are supposed to be held in separate tool holders
attached to separate slide rests worked at right angles to one another.
The edge plate O being first used and then edge plate P.
The mode of operating upon each special form of article, as well as
the shape of the edge plates, will necessarily be varied to suit the form
and character of the article to be turned or shaped.
Although I have shewn special means suitable for holding certain
articles while being turned or shaped it must be understood that the
usual and ordinary modes of holding such articles may be also employed
in conjunction with the use of my edge plate tools.
In practice I have found that tempered steel plate of the thickness
of about one hundred and sixty to the inch answers well for the edge

page_text: Fifth. The means for holding articles of potters' clay whilst turning
nd shaping the same, substantially as described.
In witness whereof, I, the said James Murdoch Napier, have here.
unto set my hand and seal, this Tenth day of November, in
the year of our Lord One thousand eight hundred and seventy-
five.
JAMES M. NAPIER. (L.S.)