For Socket Head Cap Screws
| Counter Bore Size | Clearance drill size |
| #0 | #49 (0.070) |
| #2 | #36 (0.113) |
| #4 | #29 (0.136) |
| #5 | #23 (0.154) |
| #6 | #18 (0.177) |
| #8 | #10 (0.1935) |
| #10 | #2 (0.2210) |
| 1/4″ | 9/32″ (0.281) |
| 3/8″ | 13/32″ (0.406) |
| 7/16″ | 15/32″ (0.469) |
| 1/2″ | 17/32″ (0.531) |
| 5/8″ | 21/32″ (0.656) |
| 3/4″ | 25/32″ (0.781) |
| 7/8″ | 29/32″ (0.906) |
| 1″ | 1-1/32″ (1.031) |
| 1-1/4″ | 1-5/16″ (1.313) |
| 1-1/2″ | 1-9/16″ (1.562) |
| 1-3/4″ | 1-13/16″ (1.813) |
| 2″ | 2-1/16″ (2.062) |