Are all the change wheels in place at the left of the headstock taking the drive from the spindle to the input of the threading gearbox? Note that in this lathe it starts at a small shaft projecting just below the back end of the spindle not the spindle itself. Is this turning? If not there is a problem inside the head.

The lever on the bottom left of the gearbox selects movement left and right and probably provides neutral in the middle. The lever on the right selects between leadscrew and feed shaft. Are these levers feeling like they engage the gears properly? It is possible that the lathe was 'crashed' that is the saddle being driven right into the headstock under power and a gear broken. You should be able to rotate each of the leadscrew and feed shaft by hand and feel it loose when not engaged then resist when engaged as you fiddle with the levers.

You have said you understand the saddle operation and it is working  so I assume you know about the operation of the lever on the right of the saddle.

Edited By Bazyle on 29/08/2015 21:46:37