A NEW OR IMPROVED COMPOUND SPHERICAL REST FOR ORNAMENTAL TURNING LATHES
Year: 1865

page_text: LETTERS PATENT to Thomas Hallam Hoblyn, of Rickling, in the County
of Essex, for the Invention of "A NEW OR IMPROVED COMPOUND SPHERICAL
REST FOR ORNAMENTAL TURNING LATHES."
Sealed the 24th November 1865, and dated the 25th May 1865
PROVISIONAL SPECIFICATION left by the said Thomas Hallam Hoblyn at
the Office of the Commissioners of Patents, with his Petition, on the
25th May 1865.
I, THOMAS HALLAM HOBLYN, of Rickling, in the County of Essex, do
hereby declare the nature of the said Invention for "A NEW OR IMPROVED
COMPOUND SPHERICAL REST FOR ORNAMENTAL TURNING LATHES," to be as
follows:-
This Invention relates to an improved construction of a compound spherical
rest capable of turning and ornamenting spheres, and any convex or concave
segments of circles, either on a cylinder or surface in a more simple and
economical plan than any in present use. I propose to fix upon the lathe
plate of metal with accurately turned pivot at one end thereof, the plate
fixed by means of a bolt working in a longitudinal slot for the purpose of
adjustment at any required distance from the lathe. On this pivot works
Above the bed and
another plate, also accurately faced and turned.

page_text: worm wheel, and working in bearing within the wheel, is a sliding frame,
having one of its jaws adjustable and capable of being tightened by set screws;
this sliding frame serves to contain the slide rest in which the adjusting tool
is set, also capable of being tightened by set screws. Attached to the lower
plate is a worm wheel with endless screw on a horizontal shaft, capable of
being turned by a crank handle; this worm wheel has points or indentations
on its surface near its periphery, and numbers from unity to forty-five, repeated
four times, forming quadrants of circles. The adjusting tool rest is furnished
with a slot, in which the descending arm of a vertical hand lever enters, the
fulcrum of which is set in the adjustable jaw; the use of this lever is to
advance or withdraw the adjusting tool or cutter as required. There are also
on each side of the tool rest milled-edged buttons, attached to screws which
act against the ends of the jaws, for adjusting the tool with accuracy. The
main sliding frame working on a centre renders the tool capable of being
turned in an arc of a circle during the operation of cutting, and the advance
or retrogression of the tool while being so actuated results in the formation of
a convex or concave surface, or of a pattern or ornament upon a spherical,
cylindrical, concave, or convex surface. For nice and accurate adjustment or
lateral movement of the slide rest, in order to effect minute work on ivory,
wood, or other material, the worm wheel described is made use of. I apply
to one side of the sliding frame a horizontal shaft set in bearings hinged to
the frame, which rise and fall by the action of thumbscrews; the extremity of
this shaft is furnished with an endless screw thread, which gears into the
female threads of the wheel. The other end of the shaft is provided with a
milled-edged adjusting wheel and also with a crank handle, by means of
turning which the whole slide rest and tool are caused to rotate in either
direction around the worm wheel, and thus the operation of cutting spherical,
concave, or convex surfaces is effected with the greatest accuracy.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Hallam Hoblyn in the Great Seal Patent Office on the 30
25th November 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
HALLAM HOBLYN, of Rickling, in the County of Essex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-fifth day of May, in the year of our Lord 35
One thousand eight hundred and sixty-five, in the twenty-eighth year of Her

page_text: reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Thomas Hallam Hoblyn, Her special licence that I, the said Thomas
Hallam Hoblyn, my executors, administrators, and assigns, or such others as
I, the said Thomas Hallam Hoblyn, 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 "A NEW OR IMPROVED COMPOUND SPHERICAL REST POR ORNAMENTAL TURNING
LATHES," upon the condition (amongst others) that I, the said Thomas Hallam
Hoblyn, 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 Thomas Hallam Hoblyn, 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 has for its object a new or improved compound spherical
rest for for ornamental turning lathes, which is capable of turning and orna-
menting with the greatest accuracy spheres and any segments of circles, either
concave or convex, either on the cylinder or surface; also by addition of
templates any other curves not segments of circles, in addition to all the work
now performed by a compound slide rest. It consists of A, the lower plate;
B, the top plate; C, the carriage and a saddle, as is usual. A is a strong
plate of iron, accurately planed on bottom and sides with a longitudinal
bevilled slot in the bottom to receive the fastening bolt, which can therefore
tighten up the plate at any point on the lathe bed. At one end of A is a piece
raised somewhat the whole breadth of plate, and accurately turned and faced
with a strong turned pin "6" in centre to form a pivot. Around this raised
piece is placed a wheel "c" with any specified number of cogs, and on its top
any specified number of small holes drilled to receive two pins as segment
stops. Bis the top plate, slightly narrower than A, having on the bottom of it
a corresponding surface to the raised surface on the plate A, accurately turned
and faced with countersunk hole in centre to fit well on the pivot "," on
which it is tightened by a large-headed screw with square washer underneath
to prevent unscrewing by friction. The top of B is to be accurately planed to

page_text: receive two parallel bars of brass, bevilled on the inner edge, so as to form
sliding bars for C, the carriage, one bar to be a fixture, the other capable of
adjustment by tightening screws. The sides are also to be accurately planed,
and on one is fixed a tangent screw "e," capable of being put in and out of
gear with the brass wheel "c" for the purpose of driving the top plate round the
pivot "b." Also in the raised surface on the top plate B is a countersunk slot
forming a circle with screw passing through it into the bottom plate, by
which means the top plate can be firmly fixed at any angle to the bottom
plate for the purpose of slide rest turning. Also there is a small pointer "f"
working just clear of the brass wheel intended for acting as a segment stop,
two small pins being placed in any of the specified number of holes in "c."
Also on the opposite side to the screw "e," but on the top surface, is a screw g
working in two standards screwed into the plate through slots in the bar,
which screw works through a traveller "h," firmly attached to C, the carriage,
and therefore capable of driving C in a rectilinear direction; this is for slide rest
purposes. C is the carriage, consisting of an iron plate "i" with standard "k,"
top plate "," and parallel brass bars to receive tool receptacle "m," the bottom
plate and standard to be in one piece with the plate, planed side and bottom,
so as to slide truly between the parallel bars on B. The standard is to have
its surface accurately turned with pin in centre to form a pivot. The top
plate is to be planed true, bottom, sides, and top, and to have a countersunk
hole in the exact centre, so as to work on the pin, and to be tightened up by
a large nut. Also in the plate is to be a countersunk slot forming a circle,
with screw passing through into the standard, by which means the tool
receptacle can be set either parallel with B, for spherical turning; at right
angles to B for slide turning; or at any angle for the purpose of thick and
thin cuts and similar patterns, when used either as a spherical or slide rest.
The parallel bars are to be similar to those on B, to enable the tool receptacle
to be advanced or retired, either by lever or screw, as usual in slide rests. This
part of the machine can, if so desired, be made to adjust for height of centre
in this way-The standard "k" to be a strong hollow cylinder with fixing
screw on one side; the plate "i" to be made with strong turned pin on the
bottom, so as to fit into the standard; there may also be an elevating screw,
as in the best slide rests; the saddle is the same as usual, with this exception,
that a small hole is drilled in one of the sides, and a corresponding one in the
side of the lower plate A, so placed that when a pin is fixed into these holes
the pivot is exactly central to the lathe centre. The way of using the
spherical rest is this:-When all together, and the point of tool adjusted by
means of a square exactly over centre of pivot, it is evident if the top plate

page_text: moves round, the point of the tool will still be in the same place, but if we
retire the point one half inch, on moving the plate right round it would
describe an inch circle, so that if the centre of pivot be exactly under the
centre of the lathe, and we move the rest the circle it will cut a perfect ball
(or any part of one, if the cut be less than a circle) of such size as the
distance doubled of point of tool from centre of pivot. Therefore by adjust-
ments of the lower plate on the lathe bed according to the size of material
(this, of course, does not allude to the act of turning a ball when the centre
of pivot must be exactly under centre of lathe) adjustment of carriage from
centre, according to the size of circle required, and adjustment of tool for
depth of cut, we are enabled to turn any convex curve. To turn the concaves,
instead of retiring from centre of pivot it is only requisite to advance the point
beyond the centre to the distance required, when the same rules apply as to
the convex curves. In turning the concaves, however, it is necessary to turn
the plates half round, so that A and B are in the same straight line, instead
of over each other. This enables you to work on any sized piece of wood, the
object of the longitudinal slot in the in the lower plate being to enable you to
adjust your previously arranged curve to any sized wood or ivory that your
lathe will take, less two inches, the height of machine. The desired curve
having been turned, take out the chisel, and place in the receptacle any orna-
menting instrument, drill, eccentric, &c.; advance the point till it touches the
work; then set your screw for depth of cut, and work according to fancy.
Whatever it is it must be mathematically correct on the curve, as you have
not altered it in any way. You then move your rest to cut the next desired
curve, and proceed as before. The best way to execute a piece of work is
first to make a sectional pattern of your design, either by drawing or cutting
it out with scissors from a doubled piece of paper, when, of course, both sides
come the same, the line where the paper is doubled being the line of centre
of the lathe. You can then with a pair of compasses ascertain with accuracy
the necessary size of circle, and the position of centre of pivot to procure the
desired curves. You may also produce a very good effect by a combination
of two different curves in this way:-Let your ornamenting instrument be the
universal cutter, working horizontally; follow up your curve with it, but
instead of cutting right out on your curve let the instrument finish of itself in
wood, previously turned so as to fit its curve, when you get the lesser and
greater curves following in unbroken succession. With the eccentric chuck
numberless effects of the most curious description may be produced; even
work supposed to be only possible with a rose engine, as exemplified in
plate 47 of the "Manuel du Tourneur;" this instrument will also turn a

page_text: perfect ball and two cups that shall fit the ball with mathematical accuracy, a
thing which indeed if ever practical before was only to be done with most
expensive machinery. The Chinese balls, four or five, one inside the other,
can also be accomplished, and many other of the curious forms described in
the "Manuel du Tourneur." This instrument might be made very useful for
engraving glass, as most patterns contain curves; or pottery.
Having described the nature of my Invention, and how the same may be
carried into effect, what I claim as new, and desire to protect by Letters
Patent is the following:-
First, the construction of a rest that will enable a turner to work a true
curve, both concave and convex, by having a tool holder to radiate round a
centre in such a manner that if the cutting part of the tool is between the
centre round which it radiates and the work operated upon, a concave shape
is the result, and if the work operated on is between the cutting part of the
tool and the centre round which the tool holder radiates a convex shape is
the result.
Secondly, the general construction and combination of parts as described.
In witness whereof, I, the said Thomas Hallam Hoblyn, have hereunto
set my hand and seal, this Twenty-first day of November, in the year
of our Lord One thousand eight hundred and sixty-five.
THOS. M. HOBLIN. (S.)