1. File a flat area on manufactured head 2. Center punch flat 3. Drill through head using drill one size smaller than rivet shank 4. Remove weakened head with  machin punch 5. Punch out rivet with machine punch Rivet Removal Remove rivets by drilling off the head and punching out the shank as illustrated. 1. File a flat area on the manufactured head of non-flush rivets. 2. Place a block of wood or a bucking bar under both flush and nonflush rivets when center punching the manufactured head. 3. Use a drill that is $^{1}$/32 (0.0312) inch smaller than the rivet shank to drill through the head of the rivet. Ensure the drilling operation does not damage the skin or cut the sides of the rivet hole. 4. Insert a drift punch into the hole drilled in the rivet and tilt the punch to break off the rivet head. 5. Using a drift punch and hammer, drive out the rivet shank. Support the opposite side of the structure to prevent  structural damage. Figure 4-98.  Rivet removal.  3.  Remove the head by breaking it off. Use a punch as  a lever. 4.  Punch out the shank. Use a suitabl backup, preferably  wood (or equivalent), or a dedicated backup block. If  the shank does not come out easily, use a small  drill  and drill through the shank. Be careful not to elongate  the hole. National Advisory Committee for Aeronautics (NACA) Method of Double Flush Riveting Replacing Rivets is adequately compensated by an increase in size or a greater  number of rivets. It is acceptable to replace 2017 rivets of  3 ⁄ 16-inch diameter or less, and 2024 rivets of  5 ⁄ 32-inch diameter  or less with 2117 rivets for general repairs, provided the  replacement rivets are  1 ⁄ 32-inch greater in diameter than the  rivets they replace. A rivet installation technique known as the National Advisory  Committee for Aeronautics (NACA) method has primary  applications in fuel tank areas.  [Figure 4-99]  To make  a NACA rivet installation, the shank is upset into a 82°  countersink. In driving, the gun may be used on either the  Replace rivets with those of the same size and strength  whenever possible. If the rivet hole becomes enlarged,  deformed, or otherwise damaged, drill or ream the hole for  the next larger size rivet. Do not replace a rivet with type  having lower strength properties, unless the lower strength  4-46