The present invention involves screwdriver having a grip, a driver blade insertable into and rotationally affixed to said grip and a chuck. The chuck encloses and is longitudinally displaceable relative to the driver blade. The chuck has collets extending from an end disposed near the blade tip. The collets have claws extending from their free ends which are adapted to retain a screw on the blade tip when the chuck is in a retaining position. The collets may be either inwardly biased or outwardly biased. A sleeve, for pressing the collets inward, is provided for embodiments employing outwardly biased collets. A stop device is provided for inhibiting the longitudinal displacement of the chuck towards the blade tip beyond the retaining position. The stop device comprises a groove in the blade shaft and a cooperating detent spring located on the chuck. The free end of the detent spring extends toward the blade tip and is biased inward so that it is disposed within the groove. When the chuck is in the retaining position the detent spring bears against a stop face of the groove thereby inhibiting further longitudinal displacement of the chuck relative to the blade.