| 摘要 |
A wood screw has a countersunk head having a recess for accommodating a driving tool, a tapered neck, a plurality of crown ribs extending over the head and neck and a shank including a main thread 54, a lower thread and a point. The main thread 54 has a thread form including an outer tip 154 having a linear profile and a rounded root 254 having a concave profile. |
