The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking. Paul N. Hasluck
rel="nofollow" href="#ulink_55ba6fd5-40de-5053-beb9-b15e8b69c0a0">Fig. 435 or Fig. 436, is much more convenient. The home-worker who does not care to buy an expensively mounted stone may construct a strong frame on which to mount a grindstone of 4-in. by 3-in. stuff, with the legs well spread out and braced together about 6 in. from the ground. It is sometimes a great advantage when grinding a thick heavy iron or axe to be able to stand higher on one foot. Under the stone should be a box to hold water, in which the stone will be partly immersed. Some prefer a can fixed above to allow the water to drip on the stone. Too much has the disadvantage of splashing on the ground and over the legs and boots of the grinder. Others dislike the box below the stone, as the water always left in the box tends to soften that part of the stone which is immersed in it. This can be avoided by having the box loose and letting the two end pieces run up longer than the sides. Let these pieces be of the same width at the top as the rails in the ends of frame, and with a pair of butt hinges hang one end to the frame. Nail firmly to the other end of the box a leather strap, and punch half a dozen holes in it about 1 in. apart, the end with the holes projecting above the box, and screw a stout 2-in. screw centrally into the other end rail. By this means the box with the water can be raised whilst grinding, and, when finished with, it can be dropped down a couple of holes so as to clear the stone. Thus all the advantages of a box, without its drawbacks, can be secured. It can also be easily dropped right down to the ground for cleaning out, or in the event of any small tool falling into the box, as sometimes happens. Always grind wide tools near the edges, which will help to keep the stone slightly rounding on the face.
Fig. 434.—Grindstone in Dwarf Iron Stand.
TRUEING GRINDSTONE.
When a stone gets worn out of the circle, say 1/2 in. to 3/4 in., it should be trued up again, and this is best done when the stone is dry. To do this, get two old flat files, or two short pieces of flat bar iron and a piece of stout hoop iron about 18 in. long; firmly cramp the hoop iron between the other pieces, allowing the end to project about 1/4 in., and with this turn the stone away. It is surprising how it will cut, and by turning the iron over occasionally a good cutting edge can be kept upon it. The expenditure of a few minutes occasionally will keep a stone in perfect order and make its use a pleasure instead of a trouble. Another method, probably not so good, is to true a stone with a simple piece of hard steel, such as a worn-out file, this being held so that as the stone turns it scrapes against the parts that project further than the general surface. The file must be held resting close to the scraping end rigidly against a firm part of the framing of the grindstone stand. The tool is thus made to turn down the unevenness. The point to be attended to is to hold the tool quite firmly without any motion to and from the centre of the stone corresponding with its rotation. The stone will yield to the steel more readily if well soaked in water before being treated.
Fig. 435.—Treadle Grindstone on Iron Stand.
SPEED OF GRINDSTONES.
There appears to be great differences in the speeds at which grindstones are run, but in England the speed of the face may be taken at from 800 ft. to 1,000 ft. per minute. Taking the higher of these values, the speed of a stone 1 ft. in diameter will be
The makers of Ohio and Huron grindstones state that the former should run at about 2,500 ft. per minute, and the latter somewhat higher.
Fig. 436.—Treadle Grindstone on Wooden Stand.
CHARNLEY FOREST AND TURKEY OILSTONES.
The oilstones in most general use are four in number—the Charnley Forest, Turkey, Washita, and Arkansas. The Charnley Forest oilstone is an old-fashioned English variety, and a good one will last a lifetime. This stone is of a greenishslate colour, sometimes with small red or brown spots. The lighter the colour of the stone, the more serviceable it will be. The softest and most even-grained stone should be selected, hardness being the most general defect. Stones of this variety may be good for some time, but if neglected, or if linseed oil is used, the stone will absorb the oil and become very hard, rendering a lot of rubbing necessary to sharpen a tool. A Charnley Forest oilstone may take a little more rubbing than other stones to get an edge, but it will be keen and fine, and as the stone wears slowly it seldom requires rubbing down. When two oilstones are used, a Charnley Forest stone is about the best for finishing the edge after it has been rubbed on a coarse cutting stone. The experience of many years suggests that the best stone a woodworker can select is a Charnley Forest stone, the edge produced by it enabling the woodworker to do the best work and more of it before the tool requires resharpening. Turkey stone is generally known as white, grey, and black, but its appearance is generally more or less of a mixture of brown and blue shades. It is of very close grain. Some Turkey oilstones are of a dark slate colour when oiled, with white veining and sometimes white spots. They give a keen, fine edge to tools, but wear very unevenly. In addition to this defect, they are the most brittle oilstones, great care being necessary to prevent a breakage when fitting them into a case, and a fall from the bench will generally result in cracking the stone, even after being boxed. The Turkey oilstone is a notoriously slow cutting stone; to most woodworkers its price is prohibitive.
AMERICAN OILSTONES.
The cheapest oilstone in the market at first cost is the Nova Scotia or Canada stone, which is brownish yellow in colour, and wears away rather quickly. They vary considerably in quality; one may cut like a grindstone and leave about as good an edge, whilst another may be very hard, requiring a lot of rubbing to sharpen a tool. One between the two extremes should be chosen if possible. The Washita (Ouachita) stone is yellowish-grey in colour, and though it wears away quickly it does so much more regularly than Turkey stone. Some kinds are of a whitish-grey or light buff colour when oiled. The same remarks apply to these as to the Canada stones, but they are usually finer in grain and more even in texture, and for this reason are general favourites. These stones sharpen the tools quickly, but do not leave so good an edge as is obtained with the Charnley Forest stones, and they wear away more quickly. The edge produced by a Washita stone is generally of a “wire edge” description, and rapidly becomes dull. These and other soft stones soon get full of grooves and furrows if much used for sharpening narrow tools, small chisels, or other pointed instruments, for which a hard stone should be employed. Arkansas oilstone is a compact white stone something like Washita stone, but finer in grain. It wears well and cuts slowly, being largely used for finishing the fine edges of surgical instruments. Workers generally consider them to be the best oilstones in the market, but, unfortunately, they are very expensive.
SELECTING OILSTONES.
The choice of a suitable oilstone is one of the greatest difficulties that present themselves to the woodworker when selecting his tools. The degree of hardness is important, oilstones having a tendency to become harder after being in use for a time. Many of the American oilstones are manufactured from fine grit, cemented together. Generally they are even in grain, but are often too coarse, and although they sharpen the tool quickly