Читать книгу The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking - Paul N. Hasluck - Страница 157

Oil is used not only for assisting the stone to produce a keen cutting edge, but as a lubricator to prevent the stone heating the tool, and to prevent the entrance into the stone of the metal particles rubbed off the edge of the tool whilst sharpening. The oil should not gum up or harden if left, or it will cause the stone to glaze. Either neat’s-foot oil or sperm commonly is considered best for oilstone use, all others hardening the surface much more quickly. Good for the purpose is lard oil to which sufficient petroleum has been added to prevent it becoming thick in the can in cold weather. Sweet oil or vaseline thinned with petroleum makes a good sharpening oil, in fact, any oil of animal extraction mixed with mineral oil may be used, but vegetable oils that are obtained from seeds and nuts and are used for making paint should be avoided. Sweet oil with the addition of about one-eighth of paraffin is used largely for quick-cutting stones. Petroleum, paraffin, etc., however, are not advised, the oil hardening the stone and destroying its cutting properties; where it is used for thinning oil no more than is necessary for the purpose should be added; however, if the stone becomes dirty or gummed up, a very small quantity of paraffin or turps may be used for cleansing purposes, but it should be wiped off as soon as possible. The oil may be kept for use in a small oil-can (Fig. 449). Soap has been recommended for the same purpose. The stone is wetted and rubbed with soap, and more water is applied until a lather forms. This dries, and when the stone is required for use it is merely necessary to wet it slightly.

Fig. 444.—Oilstone Case.