Material. Mild steel, 16 mm in diameter, 250 mm long.
Additional tools. 16-mm drift; bolster plate, 25 mm thick with a 16.5-mm hole; 30-mm bottom swage; bending fork and bending dog.
Both ends are upset (Fig. 86 A) in a manner similar to the hook eye (Job 10) and to the same size. Both ends are punched in the same way. Eyes are completed by passing the 16-mm drift through each to give a neat hole (not chamfered as for the hook). The centre section is heated to a bright red heat and bent, using the bending fork and bending dog as for the hook in Job 10. Take care to get the ends in line with each other and the bend an even curve (Fig. 86C). Metal bends most easily at the hottest point.
Reheat the whole job to a good red heat. Place the ends over the bolster plate as shown in Fig. 87. A few blows on the set hammer will settle the ends parallel to each other and the correct distance apart. While the job is still hot, a drift is hammered through the holes and the bolster plate to align the holes. A large nut placed on the anvil will allow the drift to clear both holes (Fig. 88).
Some shackles are upset in the centre to allow for extra wear. If these are made, additional metal is required.