Australian Hercus "Model 260" lathes - a late development of the original South Bend copy - used a slightly different arrangement of screwcutting changewheels. The metric version of the lathe, the Model 260-AM with a 3 mm pitch leadscrew and a (metric) screwcutting gearbox had the following gears fitted as standard to the changewheel bracket: 18, 45, 60 & 80 idler. To cut a full range of inch-pitch threads additional gears were required: 25, 33, 39, 42, 48, 50 and a 63/64 combination gear.
need the following gears to generate a full range of metric pitches:
Hercus Model 260 BM and 260-CM lathes with a 3 mm pitch leadscrew and changewheels for screwcutting need the following gear set to generate a full range of inch pitches: 18, 24, 25, 30, 33, 36, 39, 42, 48, 54, 60, 72, 80 and a 63/64 combination gear
Hercus Model 260-B and 260-C lathes with an 8 t.p.i leadscrew and changewheels for screwcutting need the following gear set to generate a full range of metric pitches: 18, 20, 24, 27, 33, 36, 40, 42, 48, 54, 60, 63, 72, 80 and a 60/63 combination gear..