Hercus 9 inch Model A Lathe

The model A lathe (above) features a quick change gearbox for screw cutting and feed selection and an automatic power feed apron. The gearbox provides 40 screw pitches, the  feed changes by shifting two levers in accordance with a direct reading index chart on the gearbox. A further coarse thread from 4 to 7 T.P.I. may be obtained by transposing one gear in the change gear train. The power feed apron provides powered feeds both along the bed and across  through a worm drive and friction clutch. Power is transmitted through a spline machined along the leadscrew, leadscrew  threads being used only for screw cutting. A built-in safety device prevents simultaneous engagement of halfnuts and power feeds.