Tailstock indexing
The C3 and the larger D lathes were provided with a method of driving the lathe via the lead-screw from overhead power at the tailstock, for the B2 it was an extra attachment and although it could be worked by hand it was best suited to run via the overhead drive. Driving the lathe from the tailstock is used for spiral cutting ( see video) and certain other machining operations when powered by an overhead drive or for some operations by hand. This lathe has a completely different type of mechanism to that mentioned by George Gentry and Pittler. I only recently fathomed out how the lock and release mechanism actually works. The usual Pittler method is being worked by a lever lifting the worm up to the gear wheel and does not use a special handle as on this lathe.
Above: Standard and special handle fitted with flange and two lugs.
Below: showing how the special handle (when pushed right on) locates it's two lugs into the sockets fitted on the end of the lead-screw shaft. The worm wheel rotates in an oil bath
On the left shows the special handle which replaces the standard one shown below it. This is fitted when using the lead-screw to drive the lathe from the tailstock, it has two teeth or lugs which locate on the end of the lead-screw and lock it together with the worm connected to the pulley shaft.
The spring lever shown on the photo's on the right is pushed down until it locks on a small pin held by a spring, the long rod beneath the bed has a lug which can be set to disconnect the drive via the clutch in the headstock. This works to push a lever which triggers the mechanism to release and so pushes the handle away and disconnects the drive.
Below: the lever, poised above and ready to push away the handle
Left: shows the back of the mechanism with it's various springs & levers. The slot that is visible is where the lever fitted on the rod below the lathe bed protrudes. It pushes the curved lever which then releases the main mechanisms strong spring and the locking lever jumps back up and swivels a lever down to disconnect the drive.
Above: the lever is shown before it is locked down and the spring compressed.
Below: the lever is in locked down position and the spring is compressed.
Photo on the left shows that the lever is poised to disconnect the drive when triggered by the saddle reaching the stop lug under the lathe bed.