JIG FOR TAPPING

PURPOSE: A tapping jig is provided to guide the movement of a tap toward a work piece without escaping the set central line and to prevent the tap from being broken easily even though skillful work is not performed. CONSTITUTION: A tapping jig includes an inner and an outer cylinder(2,4) combined to a tap chucking member(C), and a return unit. Herein, the outer cylinder(4) has an upper end connected to the lower portion of the tap chucking member and a lower end forming a hanging sill(12). The inner cylinder is overlapped to the outer cylinder to have flexible length. The inner cylinder has a flange(14) corresponding to the hanging sill of the outer cylinder. The return unit includes a tensile spring(16) having both ends fixed to the hanging sill of the outer cylinder and the flange of the inner cylinder respectively. The return unit makes the inner cylinder reset in an expanding form from the outer cylinder. The bore of a hole(8) on a work piece(6) is tapped as a tap(T) is rotated integrally with the tap chucking member. Thereby, a nut is processed on the work piece. After that, the tap chucking member and the tap are rotated reversely. The inner cylinder is returned to the original position by elasticity of the return unit. The return unit resets the inner cylinder to the original position when the inner cylinder is pushed out of the outer cylinder. Air in a space of an air spring is discharged slowly through an orifice. Therefore, the inner cylinder is reset completely.