How to Calculate Thread Length on a Bolt
At Arun Fasteners we are often asked about the thread length on differing size Hex Head Bolts. Below is a helpful guide. NOTE: It is
Please see below measurements relating to our most common metric washers
| Metric Form A Washer DIN 125 | Metric Form C Washer DIN125C | |||||||
| Size | I/D mm | O/D mm | Thickness mm | Size | I/D mm | O/D mm | Thickness mm | |
| M3 | 3.2 | 7 | 0.5 | |||||
| M4 | 4.3 | 9 | 0.8 | M4 | 4.3 | 10 | 0.8 | |
| M5 | 5.3 | 10 | 1 | M5 | 5.3 | 12.5 | 1 | |
| M6 | 6.4 | 12 | 1.6 | M6 | 6.4 | 14 | 1.6 | |
| M8 | 8.4 | 16 | 1.6 | M8 | 8.4 | 21 | 1.6 | |
| M10 | 10.5 | 20 | 2 | M10 | 10.5 | 24 | 2 | |
| M12 | 13 | 24 | 2.5 | M12 | 13 | 28 | 2.5 | |
| M14 | 15 | 28 | 2.5 | M14 | 15 | 30 | 2.5 | |
| M16 | 17 | 30 | 3 | M16 | 17 | 34 | 3 | |
| M18 | 19 | 34 | 3 | M18 | 19 | 37 | 3 | |
| M20 | 21 | 37 | 3 | M20 | 21 | 39 | 3 | |
| M22 | 23 | 39 | 3 | M22 | 23 | 44 | 3 | |
| M24 | 25 | 44 | 4 | M24 | 25 | 50 | 4 | |
| M27 | 28 | 50 | 4 | M27 | 28 | 56 | 4 | |
| M30 | 31 | 56 | 4 | M30 | 31 | 60 | 4 | |
| M33 | 34 | 60 | 5 | M33 | 34 | 66 | 5 | |
| M36 | 37 | 66 | 5 | M36 | 37 | 72 | 5 | |
| M39 | 40 | 72 | 6 | M39 | 40 | 77 | 6 | |
| M42 | 43 | 78 | 7 | |||||
| M45 | 46 | 85 | 7 | |||||
| M48 | 50 | 92 | 8 | |||||
| M52 | 54 | 98 | 8 | |||||
| M56 | 58 | 105 | 9 | |||||
At Arun Fasteners we are often asked about the thread length on differing size Hex Head Bolts. Below is a helpful guide. NOTE: It is
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