The sleeve is free to slide and rotate on the arbor and is operated by hand. This is useful for smaller threads since the sleeve is simply released at the end of the cut without having to guess when to stop the spindle. This feature is particularly handy when threading up to a shoulder.
When using larger dies that cannot be cut free-hand, a guide peg is fitted through the slot in the sleeve allowing it to slide but not rotate.
Alternatively, with the guide peg removed and the stop handle fitted, the sleeve is restrained by the stop handle bearing against the lathe bed.
Caution: If threading up to a shoulder under power using the pegged sleeve or stop handle modes, stop before the shoulder and finish the thread by hand.