An assembly generally comprises a collet for receiving a cutting tool shank and a lock nut for creating a gripping force between the collet and the cutting tool shank. The collet has a nose and the lock nut has a front face that is substantially flush with the nose. The lock nut further has a fastening element that mates with a fastening element of a coolant sealing ring for attaching the coolant sealing ring to the lock nut so that the coolant sealing ring may be detached from the lock nut.