Ease of cutting greatly depends on this. The shape is determined by the type of wood and cutting conditions. A saw filer will maintain the gullet shape by manually shaping the grinding wheel with a dressing stone, and the set up of his grinding machine. Variations include face angle, face length, back angle, gullet width and depth, and a frost notch (if necessary). Typical bandsaw tooth dimensions are 1-3/4" tooth space x 3/4" gullet depth x 3/4" gullet width (grinding wheel width) x 30deg face angle x 16deg back angle. Fitting means tooth dressing and involves swaging, shaping, gauging, and grinding. The tip of the saw tooth is swaged to a flare, then the sides are compressed in slightly with a shaper tool to an exact kerf. Then a final grinding pass is made. The usual gauged tolerance is +/- .005" in kerf, and < .003" side to side variation. The same grinding machinery used for gumming is used for fitting. The saw kerf is usually made this way from the base saw metal. Sometimes, however, the kerf is made with stellite or carbide tips, in which case swaging and shaping isn't needed, although gumming is still required. The kerf may also be 'set' with a punch and hammer, with the teeth bent left, right, left... Set teeth are rarely used. Benching is the leveling and tensioning of the saw. When a saw band is run on a mill it is stretched with force, and during operation the cutting edge heats up. These forces and temperatures could cause the saw to deform. Benching deforms an un-mounted saw in a way that counteracts the operating stresses. Benching is done in a dark room with a stretcher-roller machine and flat anvil. A single light at the benchman’s work station, along with ground gauges, allows the saw filer to measure level and tension. Leveling is done with a crossface hammer and stretcher-roller adjustments. Cross face hammers are available in left and right hand versions. Each filer has his own hammer which he carefully dresses. Tensioning is done with the stretcher-roll. This machine has hardened rollers above and below the saw. They rotate slowly (one is powered, while one runs free) and pinch the saw when a lever is cranked, rolling a thin strip through the length of the saw, stretching the metal where it was rolled. Careful placement and force of the rolls