(D.) Do not use one place upon the surface of the stone continually, or a groove will quickly be worn there; instead, keep the tool moving from side to side. If properly cared for, a stone will hold its face indefinitely.
Fig. 88.—Emery Wheel Dresser.
61. Emery, corundum, carborundum, and other artificial abrasive wheels have in many cases supplanted the grindstone, as they cut much more rapidly. Any one not accustomed to using them must be careful that the temper of the tool is not destroyed, as the wheel runs at a high rate of speed, and a tool in unskillful hands is easily burned. To avoid this, the tool should be held lightly but firmly against the stone, and frequently dipped in water to cool it. If an emery wheel burns badly, it may be because it needs dressing; for this purpose a diamond emery wheel dresser is the best, but on account of its cost, various devices have been patented to accomplish the same result, one of which is illustrated in Fig. 88.
62. Whetstones.—(A.) These are used to give to a tool the keen edge necessary to cut wood smoothly. The natural stone in most common use is the “Washita stone,” which is quarried in the Ozark Mountains, and is thought by many to be the best natural stone for the general use of the wood-worker; it is fast cutting, and when of the best quality is of even texture.
(B.) Many workmen prefer an “Arkansas stone,” as it is finer and harder than the Washita. It is also more expensive, however, and is better adapted to the use of woodcarvers and engravers than to the use of wood-workers in general. It is usually not so fast cutting as the best of the Washita stones, but a finer edge may be obtained by its use. There are other natural stones, but none so generally used as the above. The purchase of a natural stone is to a great extent a lottery, as only about one stone in ten has a perfectly even texture, is free from cracks, and has reasonably good cutting qualities.
(C.) If a stone needs truing, lay a piece of coarse sandpaper upon a board, and rub the stone over it until it has been ground down. The best place, however, to true up a whetstone is upon the horizontal stone of a marble worker; this is a large grindstone, several feet in diameter, mounted on a vertical shaft, upon which are placed pieces of marble to be ground to a flat surface.
(D.) Artificial oilstones, made of emery, corundum, carborundum, and other artificial abrasives, are coming rapidly into use, and, as in the case of grindstones, eventually will supplant all others in many occupations, as they cut faster than any natural stone, may be made of any degree of fineness, and are of absolutely even texture. They are also able to resist many accidents which would destroy a natural stone.
(E.) Slip stones are used to sharpen gouges and curved tools of all kinds, and may be made in any desirable shape. An oblong stone, 8” × 2” × 1”, is the size of stone in most general use by the wood-worker, and should be fitted into a box or piece of wood with a cover to keep it clean. It may be laid either flat or on its edge, as suits the workman, though the stone may be kept true more easily if it is set on its edge.
(F.) The use of the oilstone is described under topic 40, A. The oil used should be a kind that will not gum; its purpose is to prevent the glassiness which is caused by the friction of the tool over the stone. Common machine oil is used by many, lard oil by others, and kerosene, or coal oil, is claimed by many workmen to be the only oil suitable for use upon an oilstone. Any one of these oils will give satisfactory results, but kerosene keeps the stone cleaner, thereby adding to its efficiency, and for this purpose lubricates quite as well as any of those above-mentioned.