Indexing equipment
This dividing spindle, a unique design, is yet another incredible invention of von Pittler, used on B2, C3 and D lathes
Above: the indexing spindle with three additional disks. The spindle is shown fitted with the one start worm and the five start is below it. The dividing spindle was supplied as standard on the C and most of B pattern lathes, it came with two worms together with one division disk of 100 notches. The extra disks had to be purchased separately. The ones shown here appear to be made of bronze/gunmetal, they are disks of 90 notches, 84 notches and 72 notches.
The number of division combinations possible by the simple arrangement of gearing all of the 17 change-wheels into two worms, and sub dividing this by 100 notches as per the standard division plate is simply enormous and ranges from 2 to 8000 divisions.
Later versions of the Pittler lathe from the new factory at Wahren c.1901-1910 , and also re badged by George Adams, supplied a single disk with a rotating spring loaded selector and instead of notches it had four circles of holes for 100, 90, 84, 72. Although it provided all four indexing counts on one disk it was less easy to use as it involved setting a pointer into a small hole for each turn
Right: The dividing spindle is shown fitted in place of the screw cutting spindle, After each cut is made on work held in the chuck it only needs the lever swivelled round to the sector hand, locked and then the next cut made. The sector hand is then swivelled up to the locking tab and the lever moved to the pointer & locked
The lever by the rim of the disk shown below left can rotate right around, as it moves it also turns the chuck via the worm below, the disk itself remains fixed. The knob on the side swivels the locking tab into a notch.
Shown below are the adjustable spanning hands (now called sector arms) which are set according to the dividing chart requirements. Most divisions require several turns of the lever before stopping where indicated by the spanning hand and then locked, the spanning hands are then swivelled around up against the locking tab, the lever unlocked and moved to the next notch as indicated by the pointer as shown below.
On the left image the count is set to 30 (29 notches), the locking tab is on zero, a cut is made in the workpiece and the lever is swivelled round to the second pointer and locked as in the middle photo, (the chuck will turn a fraction) a cut is made and the sector arm swivelled up to the locking tab as third photo. Then the the lever is moved up to the second sector arm and so on... Each movement of the lever also turns the chuck a fraction, the amount of turn dependant on the gear wheel fitted on the mandrel and the number of teeth to be cut etc.