I IO

SHOP TOOLS.

The nature of the work that is performed in punching holesin plates, and in shearing or bending plates, points to theapplication of water-pressure to obtain the direct action requiredfor those operations. A machine on this principle, called a“ Hydraulic Joggling Press,” is shown by fig. 31.

Suitäble dies A and B are fixed in the hydraulic press. Thedotted line shows the bottom table in position, when the angleof the T bar D to be bent is placed on the top of the die A.On the ram E rising, the angle iron is bent between the twoblocks into the required form at D 2 .

Figs. 1 and 2, plate 18, show one of Tweddell’s machines forshearing chain cables. It will be observed that the knife A is

Fig. 32.

stepped, so that although the cable is cut by one stroke of themachine, it is not done at the same moment. This enablesthe cylinder to be rednced to one-half the size that would berequired were both sides of the cable to be cut simultaneously;and as the pressure employed is usually 2000 lbs. per squareinch, the reduction of diameter that can be effected is a greatconsideration, as a strong cylinder can be obtained with amoderate quantity of metal. The drawback gear B is alsoworked by hydraulic power. The machines have two ends,so that any size of cable from 3|- inches to an inch can be