Figure 4-12.  Drive punch. Figure 4-15.  Awl. Figure 4-13.  Pin punch. Figure 4-14.  Chassis punch. Figure 4-16.  Awl usage. 4 5 6 1 2 3 7 8 9 10 11 12 4-7 The pin punch typically has a straight shank characterized  by a hexagonal body. Pin punch points are sized in  1 ⁄ 32-inch  increments of an inch and range from  1 ⁄ 16-inch to  3 ⁄ 8-inch in  diameter. The usual method for driving out a pin or bolt is  to start working it out with a drive punch until the shank of  the punch is touching the sides of the hole. Then use a pin  punch to drive the pin or bolt the rest of the way out of the  hole.  [Figure 4-13] A chassis punch is used to make holes in sheet metal parts for  the installation of instruments and other avionics appliance,  as well as lightning holes in ribs and spars. Sized in  1 ⁄ 16 of  an inch, they are available in sizes from  1 ⁄ 2 inch to 3 inches.  [Figure 4-14] Available in a variety of sizes and styles, hole duplicators,  or hole finders, utilize the old covering as a template to  locate and match existing holes in the structure. Holes in  a replacement sheet or in a patch must be drilled to match  existing holes in the structure and the hole duplicator  A pointed tool for marking surfaces or for punching small  holes, an awl is used in aircraft maintenance to place scribe  marks on metal and plastic surfaces and to align holes, such  as in the installation of a deicer boot.  [Figure 4-15] Procedures for one use of an awl: 1.  Place the metal to be scribed on a flat surface. Place  a ruler or straightedge on the guide marks already  measured and placed on the metal. 2.  Remove the protective cover from the awl. 3.  Hold the straightedge firmly. Hold the awl, as shown  in  Figure 4-16 , and scribe a line along the straightedge. 4.  Replace the protective cover on the awl.  Hole Duplicator Pin Punch Chassis Punch Awl