Improvements in or relating to Polishing Bobs of Leather.
Year: 1899

page_text: Improvements in or relating to Polishing Bobs of Leather.
We, JOSEPH RIGG, Commercial Traveller, of Church Place, Yardley, in the
County of Warwick, and HENRY HART, Foreman, of 32, Regents Road, Harborne,
in the City of Birmingham, do hereby declare the nature of this invention
to be as follows:
This invention is an improved construction and production of leather polishing
bob, and its objects are firstly, to enable a bob to be formed from scrap hide
such as walrus, bull's neck, or buffalo which is now waste, secondly, to admit of a
walrus or other rare hide bob being formed of a greater breadth than is now the
case; and thirdly, the reduction of the cost of production of the bob, and the
prolongation of its life.
In carrying this invention into effect a suitable leather or hide such as walrus,
buffalo, or bull's neck is taken, preferably scrap pieces, and cut up into small
particles, pieces or lumps, or ground to a course powder, or granulated, and is
thoroughly mixed with a liquid or partly liquid cement until the said leather
pieces or lumps become thoroughly saturated and formed into an adhering
mass. After this mass has been worked to the proper pitch of dryness it is in
quantities, as may be needed, submitted to severe pressure in moulds of the shape
and size of the bob or bobs required to be made, the whole of the leather,
cuttings, pieces, or lumps, being bound or pressed together and amalgamated
through the said pressure and cement so as to form a hard set consolidated
inseparable mass which has the desired qualities for constituting a polishing
bob. During the application of the pressure, as aforesaid, any superfluous cement
is squeezed out of the mass, so that when finished the bob is perfectly dry, but if
necessary heat may be applied in a suitable manner to the moulds.
A particularly effective cement for use in the consolidation is formed by
mixing together glue, guttapercha, resin, vinegar, gum dragon, and carbon-bi-
sulphide in necessary proportions, the vinegar preventing the mass drying harsh.
The bob may be moulded solid and have its sides faced with leather, or it may
be moulded with a wood or other core, or mounting, the last named especially
with bobs of large diameter.
Granulated or powdered leather would be treated for its formation into polish-
ing bobs in a similar manner as that previously described, but it may have
leather lumps or pieces consolidated with it to form the exterior, the sides, or
the inner portion.
It is to be understood that although scrap leather has been described as being
capable of use, this invention has considerable merit when utilizing pieces of
leather other than scrap, especially having regard to walrus hide or bull's neck,
the construction of the bobs from the last mentioned material as according to

page_text: this invention obviating the necessity of frequent dressing, as in the case with
leather bobs of ordinary construction.
Dated this 29th day of March 1899
W. P. THOMPSON & Co.,
11, Burlington Chambers, New Street, Birmingham,
Patent Agents. for the Applicants.
improvements in or relating to Polishing Bobs of Leather.
We, JOSEPH RIGG, Commercial Traveller, of Church Place, Yardley, in the
County of Warwick, and HENRY HART, Foreman, of 32, Regents Road, Harborne,
in the City of Birmingham, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement:-
This invention has reference to polishing bobs of solid leather.
Those at present in use are formed from full sized solid leather pieces cut from
the best and most suitable parts of hides, such pieces being turned circular or
skimmed up true. Considerable waste of leather is the result of so forming bobs,
especially having regard to thick hides such as walrus, buffalo, and bull's neck,
which are expensive, rare and possess particular qualities as regards thickness.
Even by the use of thick hides such as enumerated the breadth or the thickness
of a solid leather polishing bob is limited.
Now according to this invention a polishing bob of leather is constructed or
built up of any size and thickness by the amalgamation through a particular
cement, as will be hereinafter defined, of a congregation of small lumps, pieces,
cuttings or granulations of the particular hide to form a hard consolidated
inseparable mass moulded to the shape and size of the polishing bob required
and having the desired polishing properties. The essential feature of this inven-
tion is the use in the cement of vinegar or a substance having similar properties-
for instance, acetic acid-which causes a thorough amalgamation of the cement
with the leather pieces or cuttings and prevents the leather bob drying harsh.
The objects attained by this invention are, firstly, the production of a solid
leather bob of unlimited breadth; secondly, the utilization of waste or scrap
parts of hides; and, thirdly, a reduction of the cost of production and an increase
in the wear.
In producing polishing bobs according to this invention leather or hide, such,
for example, as walrus buffalo, or bull's neck is selected (preferably scrap pieces
for sake of lessening the cost of production) and is cut up into small pieces or
lumps of small size, or is ground into a coarse powder or granulated, and is placed
in the quantities required in water so as to become soaked or saturated, the said
lumps or pieces swelling slightly and becoming soft thereby. After a time the
mass is taken from the water and thoroughly mixed with a liquid cement com-
posed of water, glue, resin, gum-dragon, vinegar or acetic acid, and gutta-percha
dissolved in carbon bisulphide, which cement finds its way into the pores of the
leather lumps, until they become thoroughly saturated with it, the said mixing
being continued until such times as the mass has been worked to the proper
consistency and pitch of dryness.
The important element in this cement is the vinegar or acetic acid, as by it the
fibres of the small leather pieces or lumps are caused to open out or loosen to
admit of a thorough saturation of the said pieces or lumps with the cement, and
the bobs moulded are prevented from drying harsh in the consolidation.

page_text: Portions of the mass are now taken and submitted to pressure in moulds of
the exact size (or approximately so) and shape of the bobs to be produced, the
whole of the leather pieces or lumps being pressed and bound together and
amalgamated through the said pressure and cement so as to form hard-set con-
solidated inseparable masses having the desired qualities and the exterior shapes
of polishing bobs. A mould wherein the mass is pressed together is shown in
Fig. 1 of the accompanying sheet of drawings, a bob a constructed according to
this invention being shown in position within the said mould. This mould is
simply a metal ring e resting upon a suitable base, and its inner walls and
also the face of the base are suitably greased before the mass is placed therein
and thereon, so that the bob can be knocked out fairly easy. In this sheet of
drawings a finished bob is also shown in edge view in Fig. 2 and in side view in
Fig. 3, it having upon its sides in these figs. thin leather discs which are
cemented thereon subsequent to the bob being moulded. The cement used in
the amalgamation has by experiment been found to be particularly effective
when the materials forming it have the following proportions:Water 1 pint,
glue 2 ozs., resin oz., gum dragon 1 oz., vinegar pint, and 1½ ozs. of gutta-
percha. The last named and the resin is dissolved by the carbon bisulphide.
The bobs after they leave the moulds may require to be further dried, and
this can be done by a very small heat in an oven.
The lumps, pieces or cuttings from which the bobs according to this invention
are formed need not be of any particular shape or size so long as they are small,
(say about half-an-inch) as in their congregation and consolidation they are
forced together irregular or without any arrangement.
In the drawings the bob a is solid, that is to say it is formed entirely of
amalgamated leather pieces, but it is obvious that it may be moulded around a
wooden core or on a mounting, especially in bobs of large diameter.
It will at once be seen that by this invention there is practically no limit as to
the thickness of a bob, as would be in the case of a hide such as walrus, and this
is of great importance to the metal trades; further that by constructing bobs
according to this invention the frequent dressing necessary in leather covered
wooden bobs of ordinary construction is obviated.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is-
First. In the production of a leather polishing bob of small leather cuttings
or lumps or leather granulations, the use of a liquid or partly liquid cement
having in its composition vinegar or its equivalent.
Second. In the formation of a polishing bob of leather by the amalgamation
of a mass of small leather cuttings or lumps by a liquid cement and pressure, the
use of the cement composed of the ingredients set forth.
Third. A leather polishing bob formed of leather cuttings or granulations
amalgamated with water, glue, resin, gum-dragon, vinegar, gutta-percha and
carbon bisulphide as set, forth.