SCIENCE AND TECHNOLOGY ENGLIAH FOR MECHANICAL ENGINEERING The major application of broaching techniques to helical external gears is that used by gleasons in their G-tRAC machine. This machine operates by increasing the effective radius of a hobbing cutter to infinity so that etch tooth of the cutter is traveling in a straight line instead of on a radius This allows the cutting action to extend over the whole facewidth of a gear instead of the typical 0.75 mm feed per revolution of hobbing. The resulting process gives a very high production rate, more suitable for U.S.A. production volumes than for the relatively low European volumes and SO, despite a high initial cost, is very competitive Broaching gives high accuracy and good sur face finish but like all cutting processes is limited to"" materials which must be subsequently casehardened, or heat treated giving distortionSCIENCE AND TECHNOLOGY ENGLISH FOR MECHANICAL ENGINEERING The major application of broaching techniques to helical external gears is that used by Gleasons in their G-TRAC machine. This machine operates by increasing the effective radius of a hobbing cutter to infinity so that etch tooth of the cutter is traveling in a straight line instead of on a radius. This allows the cutting action to extend over the whole facewidth of a gear instead of the typical 0.75 mm feed per revolution of hobbing. The resulting process gives a very high production rate, more suitable for U.S.A. production volumes than for the relatively low European volumes and so, despite a high initial cost, is very competitive. Broaching gives high accuracy and good surface finish but like all cutting processes is limited to “soft” materials, which must be subsequently casehardened, or heat treated, giving distortion