Geddes, JANET

Historic or legendary Scottish market woman who, on July 23, 1637, threw her stool at the dean's IMG:content-0242.jpg:[graphic] Automatic Gear-Cutting Machine. and for a numerator 1, or any whole number. In the tangent screw plan, a crank or hand-wheel is connected to the screw by a train of change-wheels. The hand-wheel has springs to lock it at the end of a revolution, and the train of change wheels can be computed to produce any desired angular motion of the index-wheel for one or more complete turns of the handwheel. For the reciprocating gear-cutters of the second cla , the tool is borne on a bar or slide, which rests against a template or former, carefully shaped. The cutting-point therefore reproduces the former by a number of reciprocations in the space. Improved gear-cutters of either cla are made automatic, so that at the end of the cutting of one space secondary feed-gearing is engaged with the index-wheel gear, and the latter receives the number of turns nece ary to give the proper spacing of the teeth and is then locked for the next traverse of the tool. The term gear-cutter is also used for the rotating tool which does the cutting. These are serrated milling-tools, carefully profiled to the proper shape by machinery which reproduces the a igned form, and one form of relieved cutter makes it po ible to grind the face of the cutting edges without vitiating the profile.