Although not constantly needed, a very useful fitting when precise positioning of the Saddle is required.
I made up a graduated handwheel for the Leadscrew on my ML7.
Mike Cox made and fitted a Leadscrew Handwheel for his Mini Lathe.
I made a slightly less sophisticated one for mine, but with an outrigger bearing similar to Alistair Sinclair's.
With 60 graduations and a 1.5mm pitch Leadscrew, each 0.025mm division is about 0.00098 Imperial thou.
As Alistair Sinclair pointed out, it is advisable to disengage the Leadscrew from the change gear train.
Otherwise, a) it takes a lot more effort to turn all the change wheels, even with the tumbler gear set to neutral. Being idle, I just remove one of the changewheels!
b) If the tumbler gears are engaged, it will take a LOT of effort to turn the leadscrew, and as soon as the chuck rotates, the setting will be lost!
Go for it!
Howard