Читать книгу The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking - Paul N. Hasluck - Страница 156

Oilstones may be purchased fitted in a case. To make the case obtain a piece of even-grained timber, fairly hard and tough, free from shakes, about 1 1/2 in. longer, 1 in. wider, than the stone selected, and of about the same thickness. The wood should not absorb oil or break away at the ends. The most uneven side of the stone is placed centrally on the wood that forms the bottom of the case, and is marked round with a scriber. A centre-bit is then used to bore out as much as possible of the wood inside the line, the remainder being cut out with a mortise chisel, and boxed down with a router or old woman’s tooth, finally cleaning out to about three-quarters of the depth of the stone. Another piece of wood slightly thinner is then boxed out in a similar manner to form the lid of the case. The bottom of the case should be eased round the edges with the chisel to enable the stone to drop in without pressure, which will leave sufficient space for the cement used to hold the stone in its place. A mixture of white and red-lead is generally used for this purpose, but should be obtained in a powdered state and mixed with gold-size. If the ordinary tub lead is used, the stone will absorb the linseed oil and will be hardened. Another cement may be made by melting glue and mixing powdered red-lead with it to form a thick paste. This is put into the case whilst hot and the stone pressed into it, the surplus cement being forced up round the edges and cleaned off before setting. After the stone is firmly fixed with the cement, the lid may be fitted on and the case cleaned off true and square, when the plainness may be relieved by chamfering or moulding the top. A bead should be placed round the bottom edge of the lid to break the joint. By placing a block of wood at each end of the stone, a much longer stroke can be taken in sharpening, and the stone tends to wear much more evenly. It also prevents the chipping of the tool should it happen to slip over the ends of the stone while sharpening. It may be better to hinge the cover of the case, and secure it by means of a small brass hook and eye as illustrated in Fig. 443, or the cover may be similarly hinged and secured at the sides. The stone can then be picked up without the cover dropping off. It also prevents injury to the stone by the cover accidentally coming off either on the bench or in the tool basket or box. Figs. 444 and 445 show methods of finishing an oilstone case, and Fig. 446 is a section of a case with a less elaborate moulding. To give the stone a better bearing on the bench when a tool is being sharpened, the bottom of the case between the ends is cut away as shown in Figs. 443 to 445. In addition to this generally a couple of nails or steel points are driven in at one end and filed off to a point, leaving about 1/8 in. below the bottom of the case (see A, Fig. 447). This gives the case a firm grip on the bench, but scratches it. A better plan is shown in section by Fig. 448. In this two small cylinders of india-rubber are glued into two centre-bit holes of about 1/4 in. or 3/8 in. diameter bored at one end of the case, one on each side. The pieces of rubber are cut to size with a knife previously dipped in water, but are made about 1/32 in. longer than the hole is deep, so as to project below the surface. They may be cemented in with thick knotting or shellac varnish. The friction of the rubber will effectually prevent the stone from slipping about when a tool is being sharpened, and the rubbers do not injure any surface upon which the case may be placed. An oilstone case should be well French polished, the polish being tinted with a little dragon’s blood or other stain if preferred. It is much easier to keep the case clean if polished than when oiled.

Fig. 443.—Oilstone in Plain Case.