A mandrel dolly is made by first fixing the mandrel securely to a strongly made bench, by means of iron clamps passing over the square end of the mandrel, and holding them in position by nuts and bolts, as shown. On the end of the hammer shaft an iron hinge is fixed, and when this is done, the hammer should be held flat and true in position upon the mandrel, and the position at which the vertical part of the hinge is to be fastened to the upright carefully marked. Then secure the hinge in the required position. Now fasten a stout lath of ash, to act as a spring, at the top of the upright beam t > an iron bracket, as shown, and over the opposite end of the lath fasten a leather strap; then fasten the lower end of the strap round the hammer shaft, so that the hammer is held suspended about Sin. above the work. When using the hammer, grasp the shaft close to the hammer head, and swing it down against the resistance of the ash lath to produce a blow upon the mandrel.

How To Make a Metalworkers' Mandrel Dolly.