| 摘要 |
PROBLEM TO BE SOLVED: To markedly suppress expenses to be spent for replacement of a finishing shell needed because of damage or abrasion of a finishing blade in a helical broach.SOLUTION: The finishing shell of a helical broach 1 is constituted by axially stacking a plurality of wafer type shells 20-20. Finishing blades 30-30corresponding to tooth grooves in a work-piece W are formed in the respective wafer type shells 20-20. Blade widths of the finishing blades 30-30are gradually increased by each of the wafer type shells 20-20from a preceding side in a finishing direction to a following side in the finishing direction. |
