A fastener driving tool includes a shaft with a working region disposed at a first end of the shaft and configured to drive a fastener, a shank portion disposed proximate a second end of the shaft and configured to couple the shaft to a power tool, and a reduced diameter torsion zone disposed between the shank portion and the working region, the torsion zone extending from a first shoulder closer to the working region to a second shoulder closer to the shank portion. A length (L) and a radius (c) of the torsion zone have been optimized so that approximately half of breakages occur in the working region and approximately half of breakages occur in the torsion zone.

A quick removal socket tool includes: a rod body that has a surrounding wall defining a recess for receiving a screwdriver head and formed with a retaining hole in spatial communication with the recess; and a sliding sleeve sleeved movably on the rod body, formed with an annular groove, and being movable relative to the rod body between a retaining position, where the annular groove is misaligned from the retaining hole so that the positioning ball is disposed within the retaining hole and a groove of the screwdriver head to retain the screwdriver head within the recess, and a release position, where the annular groove is aligned with the retaining hole so that the positioning ball is disposed within the retaining hole and the annular groove to allow for removal of the screwdriver head from the recess.

A tool connector includes a main body, an adapter, a first engaging member and a sleeve. The main body includes a driving end portion and a connecting end portion. The main body has a first receiving hole extending along the axial direction and a second receiving hole communicated with the first receiving hole. The adapter is non-rotatably disposed within the first receiving hole and includes a through hole configured for a tool head to be disposed therethrough. The first receiving hole, the second receiving hole and the through hole respectively have a first, a second and a third cross-sectional profiles being non-circular. The second and the third cross-sectional profiles are identical in shape and coaxially arranged. As viewed in the axial direction, at least one geometric feature of the second cross-sectional profile corresponds to at least one geometric feature of the third cross-sectional profile.