When chisel has been whetted repeatedly, the end of the tool becomes so blunt that it will not do satisfactory work, and it cannot be made to do so by any amount of whetting, until the surplus metal at the heel of the bevel has been removed on a grindstone.

Figure 53 shows the manner of holding a chisel on the stone. The plane iron is held similarly. The tool should make an angle of about 20 to 25 deg. with the stone If the tool is to be used for cutting hard wood, it will need to be ground at about 20 deg. If it is to be used in cutting soft wood, it will take a longer bevel. The rule is: Keep the bevel as long as the temper of the tool and the nature of the wood to be cut will allow. The sharper the angle, the easier the tool cuts. It must not be so sharp as to become nicked or break in usage.

Plenty of water should be kept flowing upon the stone, or the resulting friction will heat the steel and draw the temper, making the metal soft so that it will not stand up or hold an edge. Then, too, the water helps to keep the stone clean by washing off the particles of chisel steel which would clog up the pores of the stone.

Fig. 54 —Attachment Fastened to Wall

In freehand grinding, the stone should revolve toward the worker. It will cut faster and also help to prevent the forming of a wire edge. Try to keep the tool at a constant angle. Frequent changes of angle, intentional or not, will cause much extra labor and result in either a poor job or a waste of good metal. Move the chisel across the entire width of the stone so as not to form a hollow in the center of the stone.

Grinding freehand is not so easy as it looks, and a beginner may find it convenient to rig up a grinding device. He should, however, practice the freehand grinding until he masters it. With the rig now to be described, excellent results will be obtained with but little practice: The stone should be placed near a wall, preferably in a corner of the room. Unless the stone is to be kept true by means of a truing device, it will be safest to have it revolve from the chisel. Cut a piece of oak or other hard wood, 1¾ in. square.

Shape the ends as shown in Fig-. 55. Fasten an angle tool at one end and in the other bore a hole and insert the metal holder. This holder or toggle bolt is simply one of the irons used by marble workers to fasten the marble slabs to the wall and can be bought at any hardware store for a few cents. The common nut which ordinarily comes with it should be exchanged for a thumbnut, to facilitate rapid adjustment.

Fie- 55 — Detail of Grinding Attachment

The length of the wooden arm can only be determined by trial, as the distance of the stone from the wall, the size of the stone, the position of the rest upon the wall, and the cutting angle desired, all are factors to be considered.

Are You Ready To Move Onto The Next Lesson? Click Here….