The metric bolt thread must be produced to tolerance class "medium" (tolerance class 6g, DIN 13, parts 21- 25), for higher precision requirements (as for spinning spindles) to tolerance class "fine" (tolerance class 4h, DIN 13, parts 21- 25).

If a high accuracy in centring the clamping nut is required, the shank diameter d2 has to be manufactured to tolerance class h6.

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