"Metric Hex Jam Nylon Lock Nut Dimensions" Calculator has been developed to show dimensions of metric hex jam lock nuts with nylon insert according to the ISO standards.

Some important notes from the ISO standards:

- ISO 10511 specifies the characteristics of prevailing torque type hexagon thin nuts (with non-metallic insert) with thread from M3 up to and including M36, with product grade A for threads d ≤ M16 and product grade B for threads d > M16.

- Mechanical properties of ISO 10511 hex jam lock nuts: Steel - Property class 04 and 05.


Nominal metric jam lock nut size


Dimensions of Metric Hex Jam Nylon Lock Nuts
Metric Nut Dimensions 
Size Product
Standard Thread
Pitch da dw e h m mw s
max min min min max min min min max min
--- --- --- --- --- --- --- --- --- --- --- --- --- --- ---

Note 1: Dimensions are in mm.
Note 2: Requirements for electroplating are covered in ISO 4042 for steel nuts
Note 3: Non-preferred threads according to ISO standards: M14.
Note 4: Non-metallic insert material: Non - metallic (Ex. polyamide).
Note 5: Nut body material : steel.
Note 6: Thread Tolerance : 6H.
Note 7: m: Minimum thread height.
Note 8: mw: Minimum wrenching height.


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.
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.
Prevailing Torque Values of Lock Nuts (Metric) Shows prevailing-on torque and prevailing-off torque values of metric lock nuts.

  • ISO 10511:1997, Prevailing torque type hexagon thin nuts (with non-metallic insert)
  • ISO 4759-1:2000, Hexagon nuts — Bolts, screws, studs and nuts — Product grades A, B and C