The use of a Rack operated or lever feed tailstock is very convenient for most operations.

Robert Butler

I use a standard screw feed tailstock 95% of the time on my Myford S7.

I also have a spare ML7 tailstock fitted with a Cowells rack feed attachment, I fit and use that instead when threading with a die head.

Phil

Having had a Cowells Capstan rack-feed tailstock on the ML7 for many years, along with @CornishJack, I can compare it with the usual screw-feed tailstock and say that it is much better overall – more sensitive more instinctive and quicker in operation.
With a 1.6mm drill in the tailstock chuck and a 3mm bar of stainless in the 3-jaw it is possible to 'peck' and withdraw to clear chips with just a finger and thumb on one of the capstan bars with hardly any effort, to a depth of 12mm..
Highly recommend.
DaveD

Mine is the same but in Grey. In 1973 was fortunate to purchase the 1965/1966 year ML7BT with Brook Gryphon 2speed motor and Dewhurst control gear, with the Cowells tailstock and Trileva and QCGB already installed, with many chucks+dividing head, etc from a fellow club member retiring from workshop activities.
It took some persuasion for the budget manager to approve £327 but it has earned its keep many times over.
Back on topic, I deduce the Cowells was installed between 1965/1966 and 1973
DaveD

Edited By Meunier on 07/02/2020 20:42:39

MichaelG:

May I trouble you to elaborate your two-handed point? I'm having difficulty in envisaging a situation in which there would be more of a need for two hands with the rack feed as opposed to the screw.

I use a lever feed with great satisfaction on my S7 and can't imagine reverting to the standard arrangement. The only small disadvantage that I encounter is that the tailstock is somewhat tail-heavy when the lever is fully extended to the right. Incidentally, although I would like to try the (expensive) rack feed, the lever does allow you to vary the mechanical advantage.

.

Yes of course …

The comment was specific to the use-case of appropriately loading a centre

The rack & pinion doesn’t hold position [pressure] and therefore to lock the barrel I use my other hand
… other body parts are available.

MichaelG.

.

Yes, but it holds position better than the rack, so you typically have the option of using one hand to do the two jobs sequentially.

MichaelG.

[very dominantly right-handed, so I tend to notice these things]