M12 nyloc nut in A4 marine grade stainless steel to DIN 985. The nylon insert grips the bolt thread under vibration and dynamic loading, resisting loosening without thread locking compound - and re-usable after removal. A4 (316) marine grade gives outstanding resistance to saltwater and chloride corrosion - the right choice for coastal, marine, and pool environments. Free next-day UK delivery on orders over £50.
  • M12 nyloc nut marine grade 316 DIN 985
  • DIN 985 nylon insert nut M12 A4 marine grade stainless steel, side view
  • Nylon insert detail - M12 A4 stainless nyloc nut DIN 985
  • Simfix product label - 985A412PK20-SIM
  • Simfix product label - 985A412PK100-SIM
M12 nyloc nut marine grade 316 DIN 985
DIN 985 nylon insert nut M12 A4 marine grade stainless steel, side view
Nylon insert detail - M12 A4 stainless nyloc nut DIN 985
Simfix product label - 985A412PK20-SIM
Simfix product label - 985A412PK100-SIM

Simfix

Nylon Insert Nut DIN 985 A4-80 A4 Stainless Steel (M12)

SKU 985A412PK20-SIM
£15.60
Pack size:
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M12 nyloc nut in A4 marine grade stainless steel to DIN 985. The nylon insert grips the bolt thread under vibration and dynamic loading, resisting loosening without thread locking compound - and re-usable after removal. A4 (316) marine grade gives outstanding resistance to saltwater and chloride corrosion - the right choice for coastal, marine, and pool environments. Free next-day UK delivery on orders over £50.
£15.60
M12 nyloc nut marine grade 316 DIN 985 DIN 985 nylon insert nut M12 A4 marine grade stainless steel, side view Nylon insert detail - M12 A4 stainless nyloc nut DIN 985 Simfix product label - 985A412PK20-SIM Simfix product label - 985A412PK100-SIM
M12 nyloc nut marine grade 316 DIN 985 DIN 985 nylon insert nut M12 A4 marine grade stainless steel, side view Nylon insert detail - M12 A4 stainless nyloc nut DIN 985 Simfix product label - 985A412PK20-SIM Simfix product label - 985A412PK100-SIM

This M12 nyloc lock nut is manufactured to DIN 985 in A4 stainless steel (316 marine grade). DIN 985 specifies a standard hex nut body with a nylon insert in the upper portion of the thread. As the bolt passes through, the nylon insert deforms around the thread and creates a prevailing torque that resists loosening under vibration and dynamic loading. Unlike chemical thread lock, the nylon insert remains effective after removal and re-fitting multiple times, making it practical for assemblies that require periodic maintenance access.

Typical applications

  • Marine and coastal assemblies where vibration lock is critical
  • Boat deck fittings, marina pontoons, and offshore structures
  • Swimming pool plant and chemical process equipment
  • Coastal fencing, handrailing, and outdoor furniture in saltwater zones

Available in packs of 20 to 100, with free next-day UK delivery on orders over £50 and 30-day no-quibble returns.

Fastener styleNyloc insert lock nut
StandardDIN 985
MaterialA4 stainless steel (316)
Property classA4-70
Thread sizeM12
Thread pitch1.75 mm (coarse)
Head typeHexagon
Drive typeExternal hex (spanner)
Surface finishPlain (no plating)
HS commodity code7318163990
Recommended useMarine

RoHS and REACH compliant.

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