Self-lubricating Sharpening Stones.
Year: 1897

page_text: Date of Application, 22nd Oct., 1897
Complete Specification Left, 13th July, 1898-Accepted, 22nd Oct., 1898
PROVISIONAL SPECIFICATION.
Self-lubricating Sharpening Stones.
I, CHARLES EDWARD MASTERMAN, of Northwood, in the County of Middlesex,
Civil Engineer, do hereby declare the nature of this invention to be as follows:-
-
I make a mixture of 45 parts of argilaceous material such as china clay with
4 parts of a calcareous substance such as powdered chalk and one part of fine
emery or some siliceous material finely divided such as powdered flint. These I
thoroughly mix and combine with 50 parts of very fine sawdust or woody fibre,
or any other similar material capable of being eliminated by firing, mixing in a
sufficiency of water to make a paste. This I press into moulds of suitable size
& form, and afterwards subject to intense heat for a considerable time. I after-
wards steep it in thin oil until it has taken up all the oil it can or put it into
a hermetically sealed vessel, exhaust the air, & then admit oil which thus permeates
the material throughout its entire mass. I vary the proportions of the materials
to obtain different grades of stone for different purposes.
Self-lubricating Sharpening Stones,
I, CHARLES EDWARD MASTERMAN, of 28, Victoria Street, in the City of West-
minster, Engineer, and of Greenlees, Northwood, in the County of Middlesex, 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;-
:-
The object of my invention is to produce an artificial whetstone which shall
be sufficiently hard to be able to give a good cutting edge to steel tools and
shall at the same time be sufficiently porous to allow of its being saturated with
oil so that the necessary lubrication of the surface may be obtained without having
to add oil.
In carrying out my invention I make a mixture consisting of finely powdered
alumina or other suitable inert substance with a grinding material such as emery
powder or powdered flint or both and with a considerable proportion of finely
divided carbonaceous matter such as fine sawdust wood pulp or the like. This
mixture I form into blocks of suitable shape in moulds by means of pressure the
mixture being moistened if necessary so that when removed from the moulds the

page_text: blocks will hold together. The blocks thus obtained I fire in a suitable kiln or
furnace so as to cause the carbonaceous matter to be driven off thus rendering the
block porous.
When powdered flint is used in the mixture it should be very finely ground.
This fine grinding can be facilitated by calcining the flints before grinding them
as is the practice in glass works.
In my Provisional Specification I mentioned one mixture which I used for this
purpose.
In many cases I prefer to use magnesian limestone in lieu of chalk.
Having obtained the porous block as above described I saturate it with" oil and
for this purpose I find that wood creosote mineral creosote and mineral oils in-
cluding those which are partially solid at ordinary temperatures such as vaseline
are more particularly applicable. In order to ensure complete saturation of the
block by the oil I allow it to cool sufficiently in a perfectly dry atmosphere so
that it may not absorb any moisture before it is placed in the oil and I some-
times further ensure complete saturation by placing the block in the receiver of
an air pump and removing the air from the interstices of the material the oil
being then added without breaking the vacuum or, I draw the oil through the
block by forming a vacuum beneath it while the oil is poured on the top..
The proportions of the different materials used can be varied between such
wide limits according to the class of block required that it is not necessary to
specify any particular mixture these being well understood and I do not claim
any particular mixture but I sometimes use a mixture consisting of 45 per centum
of china clay 4 per centum of powdered chalk 1 per centum of emery powder and
50 per centum of fine sawdust.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
"
The production of artificial self-lubricating whetstones by forming by pressure
blocks of suitable shapes containing a large proportion of carbonaceous material
a sufficient amount of alumina or other suitable inert substance and a sufficient
amount of emery powder flint or other grinding material, removing the car-
bonaceous material by heat and saturating the porous blocks thus obtained with
oil, substantially as described.
Dated this Thirteenth day of July 1898