Rotary Punch Press Disk Sander Band Saw Used in the airframe repair shop to punch holes in metal  parts, the rotary punch can cut radii in corners, make washers,  and perform many other jobs where holes are required.  [Figure 4-27]  The machine is composed of two cylindrical  turrets, one mounted over the other and supported by the  frame, with both turrets synchronized to rotate together.  Index pins, which ensure correct alignment at all times, may  be released from their locking position by rotating a lever  on the right side of the machine. This action withdraws the  index pins from the tapered holes and allows an operator to  turn the turrets to any size punch desired. When rotating the turret to change punches, release the  index lever when the desired die is within 1 inch of the ram,  and continue to rotate the turret slowly until the top of the  punch holder slides into the grooved end of the ram. The  tapered index locking pins will then seat themselves in the  holes provided and, at the same time, release the mechanical  locking device, which prevents punching until the turrets are  aligned.To operate the machine, place the metal to be worked  between the die and punch. Pull the lever on the top of the  machine toward the operator, actuating the pinion shaft, gear  segment, toggle link, and the ram, forcing the punch through  the metal. When the lever is returned to its original position,  the metal is removed from the punch. The diameter of the punch is stamped on the front of each  die holder. Each punch has a point in its center that is  placed in the center punch mark to punch the hole in the correct location.  A band saw consists of a toothed metal band coupled to,  and continuously driven around, the circumferences of two  wheels. It is used to cut aluminum, steel, and composite parts.  [Figure 4-28]  The speed of the band saw and the type and  style of the blade depends on the material to be cut. Band  saws are often designated to cut one type of material, and  if a different material is to be cut, the blade is changed. The  speed is controllable and the cutting platform can be tilted  to cut angled pieces. Disk sanders have a powered abrasive-covered disk or belt  and are used for smoothing or polishing surfaces. The sander  unit uses abrasive paper of different grits to trim metal parts.  It is much quicker to use a disk sander than to file a part to  the correct dimension. The combination disk and belt sander  has a vertical belt sander coupled with a disk sander and is  often used in a metal shop.  [Figure 4-29] Figure 4-28.  Band saw. Figure 4-29.  Combination disk and belt sander. Figure 4-27.  Rotary punch press. 4-11