Figure 2-20. - Portable power shears

Figure 2-21. - Solid punch.

Figure 2-22. - Hollow punch.

the hammer. Turn the punched section over so the burred section is up, then smooth it with a mallet.

FOOT-ACTUATED SQUARING SHEARS (fig. 2-24) make it possible to square and trim large sheets. Do not attempt to cut metal heavier than the designed capacity of the shears. The maximum capacity of the machine is stamped on the manufacturer's

Figure 2-24. - Foot-actuated squaring shears.

specification plate on the front of the shears. Check the gauge of the metal against this size with a SHEET-METAL GAUGE (fig. 2-25). This figure shows the gauge used to measure the thickness of metal sheets. The gauge is a disc-shaped piece of metal, having slots of widths that correspond to the U.S. gauge numbers from O to 36. Each gauge number is marked on the front and the corresponding decimal equivalent marked on the back.

Do NOT cut wire, band iron, or steel rods with the squaring shears.

Figure 2-23. - Correct method of backing sheet metal for making a hole with a punch.