Calculation of thread lengths
Typical, unless specified in a product standard, dimensions for thread lengths (b) is calculated as follow:
- for l <= 125 mm: b = 2d + 6mm
- for 125 mm < l <= 200 mm: b = 2d + 12mm
- for l > 200mm: b = 2d + 25mm
Where l is length of the bolt and b is the threaded part of the bolt.
For bolt, where lengths l <= 0.5d the bolt should be fully threaded.
Typical thread lengths (b) for popular sizes of fasteners
|l <= 125||30||38||46||50||54||60||66||72||78|
|125 < l|
l <= 200
|l > 200||–||57||65||69||73||79||85||91||97|
Dimensions in millimetres
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Whilst the information is provided in good faith, Andrews Fasteners Ltd are not under any responsibility or liability in respect of errors or information that was found to be incorrect or for any reliance the user may place on it.