Abstract: An adaptor for securing a tool to a spindle includes a first member which can be secured to the spindle, and a second member attachable to the first member; the first and second members have through-going bores, respectively, for receiving the tool, and the second member acts as a cam for a cam follower which is received by the second member. A holding device for holding the cam follower is disposed within the second member, and a locking member may be attached to the first member. The cam follower cooperates with the locking member, and may be moved from an unlocked position, wherein the tool is locked to the spindle, to an unlocked position, wherein the tool is released from the spindle.