| THUMB SCREWS ANSI/ASME B18.17 1968 (R1983) |
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All Dimensions in Inches | ![]() |
| Screw Diameter | Head Width | Head Height | Head Thickness | Shoulder Diameter | |||||
| Max. | Min. | Max. | Min. | Max. | Min. | Max. | Min. | ||
| 6/32 | 0.1380 | 0.31 | 0.29 | 0.33 | 0.31 | 0.05 | 0.04 | 0.25 | 0.23 |
| 8/32 | 0.1640 | 0.36 | 0.34 | 0.38 | 0.36 | 0.06 | 0.05 | 0.31 | 0.29 |
| 10/24 | 0.1900 | 0.42 | 0.40 | 0.48 | 0.46 | 0.06 | 0.05 | 0.35 | 0.32 |
| 10/32 | 0.1900 | 0.42 | 0.40 | 0.48 | 0.46 | 0.06 | 0.05 | 0.35 | 0.32 |
| 12/24 | 0.2160 | 0.48 | 0.46 | 0.54 | 0.52 | 0.06 | 0.05 | 0.40 | 0.38 |
| 1/4-20 | 0.2500 | 0.55 | 0.52 | 0.64 | 0.61 | 0.07 | 0.05 | 0.47 | 0.44 |
| 5/16-18 | 0.3125 | 0.70 | 0.67 | 0.78 | 0.75 | 0.09 | 0.07 | 0.59 | 0.56 |
| 3/8-16 | 0.3750 | 0.83 | 0.80 | 0.95 | 0.92 | 0.11 | 0.09 | 0.76 | 0.71 |