Hi All,

I'm just a hobbyist enjoying my old Hercus model A. I have made all sorts of bits and pieces for my motorcycles, including cutting imperial threads.

My son has a Hercus model ARM and with the gearbox set to the slowest lead screw setting, the lead screw is spinning too fast.

We tried to cut a thread the other day with a 1mm pitch and using the correct positions on the two gear box selectors and with the chuck driven by the back gears, the thread ended up with a pitch of a little over 5mm.

We seem to have some incorrect gears? Any help would be appreciated.


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