Century Drill & Tool Machine Screw Tap

7/8-9 National Coarse Plug Style Machine Screw Tap. Precision Cut Threads. Accurately Formed For Consistent, Exact Threading. Heat-Treated And Tempered For File Hard Threads And Longer, Useful Life. Designed For Hand Cutting Applications. For Use With Tap Wrenches To Cut Internal Threads. 75% Thread Engagement. Plug Style Is The Most Commonly Used Style Of Tap -3 To 5 Threads Chamfered.