Appendix D. Drill and Screw Dimensions
Table D–1. English Sizes
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| | Clearance hole (drill diameter) | | | |
|---|
| | Close fit | Normal fit | Loose fit | | | |
|---|
| Screw size no. or diam. | Threads per inch | Drill bit gauge | Min (in.) | Drill bit gauge | Min (in.) | Drill bit gauge | Min (in.) | Head diam. typ (in.) | Washer diam. typ (in.) | Nut size (in.) |
|---|
| 0 | 80 | No. 51 | 0.067 | No. 48 | 0.079 | 3⁄32 | 0.104 | 0.116 | 0.188 | 5⁄32 |
| 1 | 72 or 64 | No. 46 | 0.081 | No. 43 | 0.092 | No. 37 | 0.114 | 0.141 | 0.219 | 5⁄32 |
| 2 | 64 or 56 | 3⁄32 | 0.094 | No. 38 | 0.105 | No. 32 | 0.126 | 0.167 | 0.250 | 3⁄16 |
| 3 | 56 or 48 | No. 36 | 0.106 | No. 32 | 0.119 | No. 30 | 0.140 | 0.193 | 0.312 | 3⁄16 |
| 4 | 48 or 40 | No. 31 | 0.120 | No. 30 | 0.130 | No. 27 | 0.156 | 0.219 | 0.375 | 1⁄4 |
| 5 | 44 or 40 | 9⁄64 | 0.141 | 5⁄32 | 0.160 | 11⁄64 | 0.184 | 0.245 | 0.406 | 1⁄4 |
| 6 | 40 or 32 | No. 23 | 0.154 | No. 18 | 0.174 | No. 13 | 0.197 | 0.270 | 0.438 | 5⁄16 |
| 8 | 36 or 32 | No. 15 | 0.180 | No. 9 | 0.200 | No. 3 | 0.225 | 0.322 | 0.445 | 11⁄32 |
| 10 | 32 or 24 | No. 5 | 0.206 | No. 2 | 0.225 | B | 0.250 | 0.373 | 0.500 | 3⁄8 |
| 1⁄4 | 28 or 20 | 17⁄64 | 0.266 | 9⁄32 | 0.286 | 19⁄64 | 0.311 | 0.492 | 0.625 | 7⁄16 |
| 5⁄16 | 24 or 18 | 21⁄64 | 0.328 | 11⁄32 | 0.349 | 23⁄64 | 0.373 | 0.615 | 0.688 | 9⁄16 |
| 3⁄8 | 24 or 16 | 25⁄64 | 0.391 | 13⁄32 | 0.411 | 27⁄64 | 0.438 | 0.740 | 0.813 | 5⁄8 |
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Table D–2. Metric Sizes (mm)
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| | Clearance hole fit | | |
|---|
| Screw size | Pitch (mm) | Close | Normal | Loose | Head, nut size | Washer diameter |
|---|
| M 1.6 | 0.4 | 1.7 | 1.8 | 2.0 | 2.9 | 3.2 |
| M 2.0 | 0.4 | 2.2 | 2.4 | 2.6 | 3.6 | 4.0 |
| M 2.5 | 0.5 | 2.7 | 2.9 | 3.1 | 4.5 | 5.0 |
| M 3.0 | 0.5 | 3.2 | 3.4 | 3.6 | 5.4 | 6.0 |
| M 4.0 | 0.7 | 4.3 | 4.5 | 4.8 | 7.2 | 8.0 |
| M 5.0 | 0.8 | 5.3 | 5.5 | 5.8 | 9.0 | 10.0 |
| M 6.0 | 1.0 | 6.4 | 6.6 | 7.0 | 10.8 | 12.0 |
| M 8.0 | 1.3 | 8.4 | 9.0 | 10.0 | 14.4 | 16.0 |
| M 10 | 1.5 | 10.5 | 11.0 | 12.0 | 18.0 | 20.0 |
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