Rotary tool flex shaft with lock pin and end cap

A handpiece for a rotary tool including a flexible power transmission shaft configured for connection at one end to the rotary tool, and at the other end to said handpiece, at least one locking formation affixed to the shaft, said handpiece comprising:

• a housing having a first end for receiving the power transmission shaft, and a second end configured for accommodating a working attachment, said housing defining a central throughbore for rotatably receiving the flexible shaft;
• at least one locking actuator disposed in said housing for releasable engagement with the at least one locking formation;
• and
• said handpiece being provided with a biasing force for biasing said at least one actuator out of engagement with the at least one locking formation, said at least one locking actuator being configured so that a user-applied force on said at least one actuator overcomes said biasing force to enable locking engagement between said at least one actuator and the at least one locking formation.