This Gainsborough tubular latch is only recommended for use with Gainsborough door knobs and levers as the follower is designed to accomodate the 7.
8mm Gainsborough spindle. Heavy sprung tubular mortice latches are for use with unsprung lever handles or knobs, or frequently opened and closed doors. For more information regarding choosing and fitting locks and latches, please see the DIY help section.