Martin

The cross-slide arrangement is similar to that on the compound (top slide).

The dial has those two grub screws, under which are spring loaded brass pads which bear on the feedscrew.

The nut which needs a split screwdriver, on the end of the feedscrew holds the handle on.

Take off the handle remove the grub screws, and springs – the brass pads won't come out until the dial is removed – and the dial is free to move on the feedscrew. That's the theory. In practice it may be stuck on the screw by the brass pads, and turns the feedscrew. It is necessary to hold the feedscrew and twist the dial to and fro to release it.

If you take off the two socket cap screws holding the mounting onto the end of the cross-slide then you can wind the feedscrew out until a "grippable" bit appears. Don't over do it.

And don't lose the teeny weeny springs and the brass pads.