The most useful kind of nut at the present time is of hexagonal form, and is indicated by Fig. 13. Such nuts, if small, are made at a quick rate by being compressed and punched in steel dies, which are fitted to machinery specially made for the purpose. But we have no machinery for making large nuts so efficient as the steam-hammer. Large nuts are easily punched and drifted by a steam-hammer while the nuts are attached to the bars from which they are made. The drifts for steam-hammers are short and comparatively thick, and the bolsters underneath the nuts are of similar proportions. When a sufficient number of nuts are punched, drifted, and cut from the bars, the shaping of the six sides is effected by placing and hammering each nut in a three-sided tool, or anvil block. The nut is held in this shaping-tool by means of a drift or mandril, having a long handle. This handle enables the smith to rotate the nut during the hammering, in order to produce the hexagonal form desired. The nuts are placed in a large forge fire or furnace, and heated to welding heat; one nut is taken out when sufficiently heated, and. the slag that may be in the opening is quickly scraped out, and the mandril or drift is then put in; the hammering upon the outside will then form the six sides without affecting the cylindrical form of the opening in the nut.