Thread

Metric SKF adapter sleeves up to size 40 have metric threads with 6g tolerances, according to ISO 965-3:1998. Larger adapter sleeves have metric trapezoidal threads with 7e tolerances, according to ISO 2903:1993.
SKF adapter sleeves with inch dimensions up to and including size 64 (12 inch shaft diameter) have Unified Special Form threads (based on the old American National form, class 3 design). Larger sleeves have Acme Class 3G, General Purpose threads.
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