| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a pipe type ball-point pen chip capable of eliminating variations in depth and width among respective grooves formed on front faces of inward projecting parts before a hammering step to securely produce the same shape for respective grooves.SOLUTION: A method for manufacturing a pipe type ball-point pen chip comprises: a ball receiving seat forming step for forming inward projecting parts 23 for a ball receiving seat on the inner peripheral face near the front end of a metal-made cylindrical body 2; a caulking step for then inserting the ball 3 and bending a narrowing edges 21 at the front end of the metal-made cylindrical body 2 inward into a circumferential shape; and a hammering step for pressing the ball 3 backward by a hummer 4, and pressing the ball 3 on front faces of the respective inward projecting parts 23 to secure gaps between inner faces of caulking parts 22 and the forward and backward direction of the ball 3 during writing. Before the hammering step, grooves 23a are formed on the front face of the respective inward projecting parts. The grooves 23a are formed on a virtual circle around the shaft center of the metal-made cylindrical body 2. |
