Abstract: An improved structure art design knife comprised of a lower cover, a front upper cover, a rear upper cover, a blade mount, a blade, a release button, and a press button. The blade mount for the blade is contained in the blade mount channel of the lower cover, with a guide slot and a number of stepped engagement notches also disposed on the lower cover. A semicircular hole is formed at the other end of the lower cover, with a tab having a hook slot situated nearby. Formed in the front upper cover that fits onto the front end of the lower cover is an elongated hole having inserted within a retention button and a retention block, and the inner side of the retention block is tapered. Formed at the back end of the rear upper cover is another semicircular hole that corresponds to the semicircular hole of the lower cover. Two insertion nocks are formed along the center of the back side of blade.

Abstract: A grinding head mounting structure including a tubular eccentric base shaft coupled to the driving shaft of the grinding machine by a screw member, an abrasive plate holder base having a bottom coupling portion coupled to the tubular eccentric base shaft by a mandrel and a triangular top platform fixed with an abrasive plate, a swinging member having an arched base movably mounted around a circular block on the machine base of the grinding machine by a split ring and a clamp and a rectangular top coupling portion coupled to a rectangular block on the abrasive plate holder base.

Abstract: A sand belt device can be mounted detachably on a body portion of a portable grinding machine so as to replace a grinding wheel of the portable grinding machine. The sand belt device includes a positioning member which has a front part and a rear part that is fitted tightly and detachably around an annular flange of the body portion. The rear part has a hole through which a rotatable shaft of the body portion passes. A roller unit includes a driven roller and a driving roller which is mounted detachably on the rotatable shaft of the body portion and which is rotatable with the rotatable shaft. An elongated belt frame has a front end and a rear end that is attached stationarily and detachably to the front part of the positioning member. A supporting unit, which is mounted movably to the elongated belt frame, is used to support the driven roller so as to position the driven roller in front of the elongated belt frame. An endless sand belt passes over the roller unit and the elongated belt frame.