A thumb screw has a specially designed head that makes it easy to turn with one hand and ideal for use on parts that are frequently moved such as an access panel. The heads are winged, knurled or vertically tall and flat to provide an easy grip. A stainless steel screw is good for exterior applications. Use thumb screws from Grainger for easy maintenance and replacement of essential machine components.
| Nominal Diameter d | 6# | 8# | 10# | 12# | 1/4 | 5/16 | 3/8 | 7/16 | 1/2 | |
| dc | max | 0.45 | 0.51 | 0.58 | 0.71 | 0.83 | 0.96 | 1.09 | 1.4 | 1.54 |
| min | 0.43 | 0.49 | 0.54 | 0.67 | 0.8 | 0.91 | 1.03 | 1.35 | 1.46 | |
| k | max | 0.28 | 0.32 | 0.39 | 0.45 | 0.52 | 0.64 | 0.71 | 0.96 | 1.09 |
| min | 0.26 | 0.3 | 0.36 | 0.43 | 0.48 | 0.6 | 0.67 | 0.91 | 1.03 | |
| h | max | 0.08 | 0.09 | 0.1 | 0.11 | 0.16 | 0.17 | 0.22 | 0.27 | 0.33 |
| min | 0.06 | 0.07 | 0.08 | 0.09 | 0.14 | 0.14 | 0.18 | 0.24 | 0.29 | |
| L | max | 1 | 1 | 2 | 2 | 2.5 | 3 | 3 | 4 | 4 |
| min | 0.25 | 0.38 | 0.38 | 0.38 | 0.5 | 0.5 | 0.75 | 1 | 1 | |