Hello stuarth44
Here is the method of brise-copeaux
The chalking process
this lathe possess neither a thread dial indicator nor means for reeversing the direction of drive must fall back upon a very old system of positioning the cut namely , that of chalking the change wheels . Here it is necessary to stop to stop the lathe during the first cut , keeping the clasp nut engagead and to chalk a tooth on the mandrel gear , making a coinciding chalk mark on the head-stock
Similarly, a tooth is chalked on the leadscrew gear/wheel and a similar mark made on the lathe bed to coincide with it.
The clap nut may now be disengaged and the lathe carriage returned to the start as before , but the clasp nut must to be engaged for the following cut until all the chalk mark coincide .
A+