"Hex Jam Nut (Hex Thin Nut) Dimensions - Metric Fine Pitch" Calculator has been developed to show dimensions of metric jam nuts (hex thin nuts) according to the ISO standard.

Some important notes from the ISO standards:

- ISO 8675 specifies the characteristics of hexagon thin nuts (chamfered), with metric fine pitch thread, with nominal threads from M8 mm up to and including M64, with product grade A for threads d ≤ M16 and product grade B for threads d > M16.

- Mechanical properties of ISO 8675 hex thin nuts: Steel - d ≤ M39 - Property class 04, 05 , Stainless steel - d ≤ M24: Property class A2-035, A4-035 , M24 < d ≤ M39 - Property class A2-025, A4-025


Nominal metric hex thin nut (jam nut) size


Dimensions of Metric Hex Jam Nuts
Metric Jam Nut Dimensions 
Size Product
Standard Pitch da dw e m mw s
max min min min max min min max min
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Note 1: Dimensions are in mm.
Note 2: Requirements for electroplating are covered in ISO 4042 for steel nuts
Note 3: Requirements for nonelectrolytically applied zinc flake coatings are covered in ISO 10683 for steel nuts.
Note 4: Non-preferred threads according to ISO standards: M3.5, M14, M18, M22, M27, M33, M39, M45, M52, M60.
Note 5: Thread tolerance of hex thin nuts is 6H.


Product Grade A, Grade B and Grade C: The product grades refer to the size of the tolerances where grade A is the most precise and grade C is the least precise as defined in the ISO 4759-1:2000 standard.


Link Usage
Metric Thread Size and Tolerance Calculator Calculates basic major, minor and pitch diameters of the metric external (bolt) thread and internal (nut) thread according to ISO 724:1993 standard. In addition to basic size calculations, tolerance calculations of different tolerance classes can be done according to ISO 965-1:1998 and ISO 965-2:1998 standards.
Jam Nut (Hex Thin Nut) Dimensions (Metric) - Coarse Pitch Thread Shows dimensions of a selected jam nut (hex thin nut) with coarse pitch thread.
Nut Grades, Identification Markings and Strength (Metric) Shows proof strength and Vickers and Brinell hardness values of metric nuts made of carbon steel and alloy steel.

  • ISO 8675:1999, Hexagon thin nuts (chamfered) with metric fine pitch thread — Product grades A and B
  • ISO 4759-1:2000, Hexagon nuts — Bolts, screws, studs and nuts — Product grades A, B and C