Tailstock Drive
Most versions of the Pittler C3 were supplied with the means to drive the leadscrew via the tailstock end of the lathe, this required power from an overhead drive to the pulley fitted on the tailstock mechanism. Although it could also be worked by hand it was best suited to run via the overhead drive. Driving the leadscrew from the tailstock end is used for spiral cutting and certain other machining operations . The power goes along the leadscrew, up through the reversing gears to the mandrel where it turns both the chuck and saddle very slowly according the worm and worm wheel used.
In the photo below left can be seen the large carriage handle on the end of the leadscrew and normally used to quickly traverse the saddle for general use, to the left of it is a large worm wheel and below it a worm. The long activation lever is used to raise the worm via an eccentric shaft to locate on the worm wheel which then locks in place. It can be automatically released by movement of the saddle against the rod underneath the bed or via the knob on the front of the casting, some versions of the C3, notably those plated by George Adams, use a hinged mechanism to lift the worm up. The automatic stop is triggered in either direction by adjustable stops on the long rod that runs beneath the lathe bed. The handle in the foreground is used to traverse the leadscrew by hand via the worm and gear. This is used as an alternative to overhead drive power to the pulley at the rear of the same shaft, however it requires very many turns to move the saddle just a fraction so rarely used this way.
Above: The mechanism to power the leadscrew from the tailstock end. The front handle can turn it manually but it will move the saddle extremely slowly
Above: the tailstock centre insert with very slight as yet unknown taper
The worm gear shown connected with the worm after raising the activation lever, the knurled knob also releases the mechanism if required
The tailstock of the Pittler C3, these were available with a hollow quill and a drawbar at additional cost, this required the end of the quill adapted for 15mm collets. This lathe has no drawbar facility for the tailstock but has a small, as yet unknown taper somewhere between MT1 & MT2 to accept centres, drill chucks etc. The remainder of the quill is solid.
Above: The auto stop wingnuts can be tightened on the rod that runs below the bed, the one on the left can disengage the headstock clutch when running the lathe in the direction of the chuck.
For tailstock drive of the leadscrew the stops can be set to disengage when running in either direction. When approaching either the chuck or the tailstock end the lathe the mechanism will release the worm wheel from the worm at the given setting. When running the leadscrew via the headstock belt then the same rod can be used to stop the saddle by pushing open the clutch inside the headstock. The clutch can usually be viewed and oiled in an aperture behind the makers plate on the rear of the headstock.
Note: The automatic stop would have been originally used in factory production when one man could attend a whole row of machines, moving along the row and resetting the tool and the trip mechanism on each lathe one by one.