Reduction tool for tube utilized for production of needle-like ballpoint pen tip, has shaping hole formed on line on side of rod-shaped body to reduce diameter of tube for tip element by interference-fitting of end of tube into end of hole

摘要

The tool has a shaping hole (30) formed on a center axis line on a side of a rod-shaped body (20) to reduce diameter of a tube (1) for a tip element by interference-fitting of an end of the tube into an end of the shaping hole. Inner diameter of the shaping hole gradually increases from the end to another end. One of the ends of the shaping hole is formed in a trumpet shape. An extension hole (36) exhibits larger inner diameter than the shaping hole and communicates with the shaping hole. A connection hole (34) is formed between the shaping hole and the extension hole.