| Boring Bar (cuffer bar) | (english) A combination tool holder and shank. |
| Boron (chemical symbol B) | (english) Element N. 5 of the periodic system. Atomic weight 10.82. It is gray in color, ignites at about 1112 (degrees) F. and burns with a brilliant green flame, but its melting point in a non-oxidizing atmosphere is about 4000 (degrees) F. Boron is used in steel in minute quantities for one purpose only- to increase the hardenability as in case hardening and to increase strength and hardness penetration. |
| Boron Steels | (english) The addition of boron in the range 0.0005-0.005% to certain steels increases the hardenability. A range of boron steels is now listed in the current BS 970 and are widely used for the production of cold headed fastenings. |
| Boss | (english) A projection or an enlarged section of a casting through which a hole may be machine. |
| Bottle Top Mold | (english) Ingot mold, with the top constricted; used in the manufacture of capped steel, the metal in the constriction being covered with a cap fitting into the bottle-neck, which stops rimming action by trapping escaping gases. |
| Bottom Die | (english) The stationary half-die. |
| Bottom Up | (english) Reversing the wrap of a coil putting the top surface on the bottom. |
| Bow | (english) The lateral deviation from straightness |
| Box | (english) Interanl (female) threaded end. |
| Box Annealing | (english) Annealing a metal or alloy in a sealed container under conditions that minimize oxidation. In box annealing a ferrous alloy, the charge is usually heated slowly to a temperature below the transformation range, but sometimes above or within it, and is then cooled slowly; this process is also called close annealing or pot annealing. |