Fig. 80. Left. Fig. 79. Center. Fig. 81. Right.
[Figure 82] shows some holes that could be punched while the metal is hot. A hole like the one shown at A, is made with a punch of that shape; the next hole is made with the same punch. Afterwards the hole is upset or shortened by heating and cooling each side of the hole. The bar is then hammered on the end. This shortens and spreads the metal. The hole is made true by driving a round punch thru it. The stock used for this exercise should be soft steel.
Fig. 82.
Exercise No. 10.—A Grab Hook for a Log Chain.
Fig. 83.
Fig. 84. Fig. 85.