|
Not
really computers or electronics at all, but I find it useful to know what is equal to what
when buying screws. (Metric measurements are in mm and imperial in inches, all sizes are approximate) |
Screw Size Equivalents
|
Not
really computers or electronics at all, but I find it useful to know what is equal to what
when buying screws. (Metric measurements are in mm and imperial in inches, all sizes are approximate) |
Diameter |
Common Lengths | Clearance Hole | Pilot Hole | ||||
| Gauge | Metric | Imperial | Metric | Imperial | Metric | Imperial | Metric |
| 2 | 2.0 | 1/4 - 1/2 | 6.5 - 13 | 3/32 | 2.5 | 1/16 | 1.6 |
| 3 | 2.5 | 3/8 - 1 | 10 - 25 | 7/64 | 3.0 | 1/16 | 1.6 |
| 4 | 3.0 | 1/4 - 11/2 | 6.5 - 38 | 1/8 | 3.5 | 5/64 | 2.0 |
| 6 | 3.5 | 3/8 - 21/2 | 10 - 65 | 5/32 | 4.0 | 5/64 | 2.0 |
| 8 | 4.0 | 3/8 - 31/2 | 10 - 90 | 3/16 | 5.0 | 3/32 | 2.5 |
| 10 | 5.0 | 1/2 - 4 | 13 - 100 | 7/32 | 5.75 | 1/8 | 3.5 |
| 12 | 5.5 | 3/4 - 5 | 19 - 125 | 1/4 | 6.5 | 1/8 | 3.5 |
| 14 | 6.5 | 11/4 - 6 | 32 - 150 | 1/4 | 6.5 | 5/32 | 4.0 |
| BA Screwsize | Metric outside diameter (mm) |
| 8 | 2.2 |
| 7 | 2.5 |
| 6 | 2.8 |
| 5 | 3.2 |
| 4 | 3.6 |
| 3 | 4.1 |
| 2 | 4.7 |
| 1 | 5.3 |
| 0 | 6.0 |
It is increasingly
common to find metric screws on sale.
Although a simple concept it causes me great confusion, and doing a reasonably accurate
conversion to decide upon equivalents invariably ends up with a box of screws the
wrong length.
The following diagram helps no end. Metric lengths are shown in blue, and imperial lengths
in green. The bars are drawn to scale to help make clear that 25mm is pretty close to
1", but an 80mm screw may well break through a piece of 3" timber.
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