Abstract: A portable power grinder for operating a wheel type of grinding tool, comprising an output spindle (12) drivingly connected to a rotation motor (11) and provided with a threaded coaxial bore (23) for receiving a grinding tool clamping screw (24) and with a radial support flange (25) for backing the grinding tool when clamped to the output spindle (12). An easily exchangeable tool support element (28) is sandwiched between the grinding tool and the support flange (25) and is provided with a coaxial through opening (30) for the clamping screw (24) and a forwardly directed tubular neck portion (27) for centering cooperation with a corresponding opening in the grinding tool.

Abstract: A portable power tool for operating a wheel type grinding or cutting working implement comprises a housing (10), a rotating output spindle (11) with a working implement supporting flange (14), a safety guard (16) adjustably supported on a guide flange (15) on the housing (10), and a selectively operable arresting device (18) for positively engaging lock openings (20) on the safety guard (16) for locking the latter in alternative positions relative to the housing (10), wherein the support flange (14) is provided with a number of peripheral indentations (21), and the arresting device (18) comprises a lock bolt (19) which is longitudinally shiftable between a first position in which it engages either one of the lock openings (20) on the safety guard (16), a second position in which it engages either one of the lock openings (20) on the safety guard (16) as well as either one of the support flange (14) indentations (21), and a third position in which it neither engages anyone of the safety guard (16) lock opening