From the Anvil Beeswax Oval Mortice/Rim Knob Set

 

These knobs come unsprung. They are solid cast, not hollow and have loose roses to enable them to be used with a rim lock (discard one rose) or use with a mortice lock.

 

They have treaded spindles to take adjustment for various door thicknesses and lock firmly with a grub screw. Each set comes complete with fixing screws, which are concealed for improved appearance,together with two escutcheons. For best results the centre of the knob should be a minimum of 3' from the edge of the door. Heavy Duty latches 18299/4' or 18299/5' are recommended for maximum efficiency.

Not suitable for external use see code 33251.

Supplied with necessary fixing screws. The GRUB SCREW should locate on the 'V' in the shaft and not on the threaded part.