An electrical discharge machining spindle for releasably holding an electrode , the spindle comprising: an elongated spindle body having a longitudinal axis; a movable sleeve surrounding the spindle body and extending along the longitudinal axis; a first contact element having a first electrode clamping surface comprising a groove extending along the longitudinal axis, the groove configured to receive the electrode therein; a second contact element having a second electrode clamping surface adjacent the first electrode clamping surface of the first contact element ; an electrode guide including a passageway and configured to guide the electrode toward the first and second electrode clamping surfaces ; a locking element that is actuated by the sleeve to selectively apply pressure to the second contact element ; wherein the sleeve is moveable along the longitudinal axis between: an open position in which the sleeve releases a pressure applied to the locking element , thereby releasing a pressure applied to the first and second electrode clamping surfaces of the first and second contact elements ; and a clamping position in which the sleeve applies pressure to the locking element to force the locking element against the second contact element to clamp the electrode within the groove and between the first and second electrode clamping surfaces ; and a biasing element biasing the sleeve into the clamping position, characterised in that pressure from the locking element forces the second contact element to shift toward the first contact element ; and the first contact element with the groove is non-movable for clamping and releasing the electrode . an elongated spindle body having a longitudinal axis; a movable sleeve surrounding the spindle body and extending along the longitudinal axis; a first contact element having a first electrode clamping surface comprising a groove extending along the longitudinal axis, the groove configured to receive the electrode therein; a second contact element having a second electrode clamping surface adjacent the first electrode clamping surface of the first contact element ; an electrode guide including a passageway and configured to guide the electrode toward the first and second electrode clamping surfaces ; a locking element that is actuated by the sleeve to selectively apply pressure to the second contact element ; wherein the sleeve is moveable along the longitudinal axis between: an open position in which the sleeve releases a pressure applied to the locking element , thereby releasing a pressure applied to the first and second electrode clamping surfaces of the first and second contact elements ; and a clamping position in which the sleeve applies pressure to the locking element to force the locking element against the second contact element to clamp the electrode within the groove and between the first and second electrode clamping surfaces ; and an open position in which the sleeve releases a pressure applied to the locking element , thereby releasing a pressure applied to the first and second electrode clamping surfaces of the first and second contact elements ; and a clamping position in which the sleeve applies pressure to the locking element to force the locking element against the second contact element to clamp the electrode within the groove and between the first and second electrode clamping surfaces ; and a biasing element biasing the sleeve into the clamping position, characterised in that pressure from the locking element forces the second contact element to shift toward the first contact element ; and the first contact element with the groove is non-movable for clamping and releasing the electrode . <EOS>