Two balls can reliably retract for smooth insertion of a tip tool into a tool holder. A hammer drill includes a tool holder, two balls in reception holes in the tool holder, a guide washer urging the balls forward in the reception holes with a coil spring, a pressure ring adjacent to a front of the guide washer, and an operation sleeve allowing the pressure ring to move backward and forward between locked and unlocked positions of the two balls. The guide washer includes, on its front surface, a projection toward the pressure ring to cause, with the pressure ring at the locked position, the guide washer to be inclined with respect to an axis of the tool holder for a first ball to move more backward than a second ball.

A bit retention assembly, for securing a tool bit to a spindle of a rotary hammer, includes a plurality of detent members movable in unison from a locking position to an insertion position in response to insertion of the tool bit within the spindle, a biasing member configured to bias the detent members toward the locking position, and a collar movable along the spindle between a first axial position and a second axial position. The collar has an annular wall at least partially defining a pocket. A first end of the biasing member is received within the pocket when the detent members are in the locking position such that the first end of the biasing member is radially constrained by the annular wall.

A power tool includes a spindle rotatable about an axis and a bit holder supported by the spindle, the bit holder including a recess configured to receive a tool bit to couple the tool bit for co-rotation with the spindle about the axis. The bit holder further includes a sleeve movable along the axis between a locked position, in which the bit holder prevents removal of the tool bit from the recess, and an unlocked position, in which the tool bit is removable from the recess. The sleeve is coupled for co-rotation with the spindle.