32. Bench and Measuring Tools.—Another set of blacksmith appliances includes the bench vise, chisels, center punch, rule, dividers, calipers, scriber, square, bevel, hack saw, and files.
Fig. 18.—The Bench Vise.
33. The bench or box vise ([Fig. 18]) is not ordinarily used in general blacksmithing. The back jaw of a general smith’s vise extends to the floor, forming a leg, and is held in position on the floor by a gudgeon on its end. This vise is not illustrated, because the bench or box vise is preferable for manual training work.
The vise should be set so that the tops of the jaws are at the height of the elbows,—a position convenient in filing. It is used for holding the work for filing, chipping, twisting, and sometimes for bending. But when it is used for bending, especially when bending a right angle, the operation should be performed cautiously, for the sharp edges of the jaws are very liable to cut the inner corner of the angle and cause a gall which will weaken the metal at the bend.
34. The chisels (A and B, [Fig. 19]) are very familiar, yet, though they are so common, they are the most abused tools used by both skilled and unskilled workmen. The mere name “cold chisel” seems to convey the impression to most people that with it they ought to be able to cut anything. But that impression is wrong; chisels ought to be made of a certain grade of steel and drawn for either rough or smooth work, as may be required. Then they should be properly tempered to cut the material for which they are intended.
A chisel for rough, heavy work should not be drawn too thin or too broad at the cutting edge. If it is flattened out into a fan-shaped cutting edge, there should be no surprise if it breaks, for, in order to make a chisel stand rough usage, it should have sufficient metal to back up the corners. On the other hand, a chisel for smooth finishing work can safely be drawn thin but not fan-shaped, as the cuts that ought to be required of such a chisel should not be heavy. A chisel for ordinary work ought to be ground so that the two faces form an angle of 60 degrees; if the work is heavy, it should be ground even more blunt.
Fig. 19.
A, cold chisel; B, cape chisel; C, center punch; D, rule.
The chisel illustrated at A represents a common cold chisel, which can be used for various purposes. The chisel B is called a cape chisel and is used for cutting and trimming narrow grooves and slots. It is indispensable for cutting key seats in shafting or work of that kind. On account of its being used in such narrow places it is necessary to make the cutting edge somewhat fan-shaped to prevent the chisel from sticking fast; but for additional strength the metal is allowed to spread, as shown. When using the cape chisel, it is a good practice occasionally to dip the cutting edge in some oily waste, which will tend to prevent its wearing away or sticking.