Abstract: A screw of the present invention includes a rod defining an axis along its orientation. The axis locates at a center of the rod. The rod has a surface being formed with at least one rod thread. A head is axially extended from the rod, and the head has a surface being formed with at least one head thread. The head is a cone or a pyramid. The largest transversal cross-section of the head is larger than a transversal cross-section of the rod.

Abstract: A bank cutter positioning device installed in a cutter seat at a side having a dovetail groove comprises a locking block, an elastic element, a roller and a handle. The locking block having an end pivotally installed above the dovetail groove. The elastic element installed between a resisting surface of the seat and a locking block. The roller pivotally at another end of the locking block. Therefore, by moving the handle, the roller of the locking block will move circularly on the sliding surface and curved surface at the lower side of the handle so as to control the releasing and locking operation of the locking block. The roller causes the driving distance between the locking block and the handle to reduce to suit a dovetail seat with a contact surface having a small tilt angle, and has the effects of rapid positioning and detaching.

Abstract: A bank cutter positioning device installed in a cutter seat at a side having a dovetail groove comprises a locking block, an elastic element, a roller and a handle. The locking block having an end pivotally installed above the dovetail groove. The elastic element installed between a resisting surface of the seat and a locking block. The roller pivotally at another end of the locking block. Therefore, by moving the handle, the roller of the locking block will move circularly on the sliding surface and curved surface at the lower side of the handle so as to control the releasing and locking operation of the locking block. The roller causes the driving distance between the locking block and the handle to reduce to suit a dovetail seat with a contact surface having a small tilt angle, and has the effects of rapid positioning and detaching.

Abstract: A quick positioning device of a bank knife installed with a positioning device on one side of the knife seat body having a dovetail groove is disclosed. The positioning deuce comprising: a locking block pivotally installed on the knife seat body; an elastic element ejecting against the locking block; a handle pivotally installed on the knife seat body, one end of the handle being connected with linkages, one end of the linkages being connected to the locking block, another end of the handle being formed as a movable portion. When the knife seat body is located across the dovetail seat by the dovetail groove, by moving the movable portion of the handle, the linkage is driven to push the locking block so that the locking block will tightly resist against the dovetail seat. Thus the knife seat body may be positioned on the dovetail seat quickly.

Abstract: A cutting tool including a dovetailed tool rest, which has a dovetail platform, a rack longitudinally adjustably mounted on the dovetail platform platform, and two scales longitudinally bilaterally disposed on the dovetail platform along the rack, and a plurality of cutting tools equidistantly mounted on the dovetailed tool rest and bridged over the rack, each cutting tool having a casing mounted on the dovetail platform by a dovetail joint and fixed in position by a tightening up screw, a cutter blade extended out of the casing, and a coupling block fixedly fastened to the casing to hold a high-pressure air tube.