Читать книгу The Handyman's Book of Tools, Materials, and Processes Employed in Woodworking - Paul N. Hasluck - Страница 75

As stated above, when a plane-iron has been sharpened on the oilstone a number of times the edge becomes thick as in Fig. 192, when the portion shown black in the drawing should be removed by the grind-stone. Of course it might be taken off with the oilstone, but this would involve a waste of time, the more economical plan being to keep the oilstone simply for imparting a keen edge, and using the grind-stone to take off the waste material at the back as occasion requires. The iron may be ground as follows: The worker should stand, if possible, with the grindstone revolving towards him. The stone should be well wetted, as a dry grindstone will heat the tool and spoil its temper. The back iron may be kept on the plane cutter and set about 1/8 in. back. This allows of a firmer grip being taken of the iron, and forms a gauge for keeping the cutting edge square, if it should be required. Fig. 193 shows the method of holding the tool on the stone; it should first be held towards the top, and the iron gradually lowered towards the worker until the bevel of the iron fits the stone, which may be felt by the additional force required to keep the tool in position. The grinding should be stopped just before the cutting edge is reached, unless it is required to remove a gap. or the iron is out of square. Some grind the iron until there is a wire edge 1/16 in. long attached to the cutting edge, and as this has to be removed with the oilstone, that much of the iron is wasted, leaving the tool at the finish exactly the same as if the grinding had been stopped just before it reached the edge. The iron should not be ground too thin, or it will chatter. On the other hand, if too thick, it will soon require grinding again. If the angle is made about three times as long as the iron is thick, it will give a good working result. A mechanical appliance for maintaining the plane iron at a certain angle on the grindstone is illustrated by Fig. 194, which is self-explanatory.

Fig. 193.—Grinding Plane Iron.

Fig. 194.—Tool-grinding Rest.