| 摘要 |
PURPOSE:To simultaneously cut and chamfer a pitch groove to a required depth in bottom and shoulder parts of a caliber, by rotating a rolling roll while turning a hob cutter, forming an edge point in a predetermined tilt angle, to be advanced. CONSTITUTION:A hob cutter 34, having an edge point in a predetermined tilt angle, is set to a head 36, and the cutter 34 is moved to the center of a caliber 9 in a rolling roll 11 by a parallelly moving bed 21. And a pitch groove cutter, while turning the hob cutter 34 to be advanced with the head 36 by a right angular moving bed 26, rotates the rolling roll 11 synchronously with the hob cutter. In this way, the hob cutter 34 cuts thread-shaped pitch grooves 33 placing their right ends to rise up in the caliber 9 of the rolling roll 11 to a predetermined depth of cut by rotating the rolling roll 11 in several turns. In this way, the thread-shaped pitch groove can be correctly further promptly cut. |
