Auto-Lok Nuts

Auto‑Lok Nuts self-locking nuts, are nuts which are slotted. A slot has been cut across the width, after which a predefined force has been used to close the slot slightly.

When installing the nut, the slot will open again to allow full install of the nut over the full length of the thread. As the slot will want to close again due to the applied stress, the nut locks itself in position.

There are 2 different kind of slotted versions:

– Single Slotted

– Double Slotted

The double slotted Auto‑Lok Nuts are also available in Imperial sizes.

Double Slotted Auto‑Lok Nuts

Stainless Steel 316 A4-80 Metric Standard ALNdM Series

Stainless Steel 316 A4-80 Imperial with Washer ALNdw Series

SS 316 Double Slotted Nuts ALNdw Series
  • ALNdw10-24A4
  • ALNdw1/4-20A4
  • ALNdw5/16-18A4
  • ALNdw3/8-16A4
  • ALNdw7/16-14A4
  • ALNdw1/2-13A4
  • ALNdw5/8-11A4
  • ALNdw3/4-10A4
  • ALNdw10-32A4
  • ALNdw1/4-28A4
  • ALNdw5/16-24A4
  • ALNdw3/8-24A4
  • ALNdw7/16-20A4
  • ALNdw1/2-20A4
  • ALNdw5/8-18A4
  • ALNdw3/4-16A4

Stainless Steel 316 A4-80 Metric with Washer ALNdwM Series

SS 316 Double Slotted Nuts ALNdwM Series
  • ALNdwM4X070A4
  • ALNdwM5X080A4
  • ALNdwM6X100A4
  • ALNdwM8X125A4
  • ALNdwM10X150A4
  • ALNdwM12X175A4
  • ALNdwM14X200A4
  • ALNdwM16X200A4

Single Slotted Auto-Lok Nuts

Stainless Steel 316 A4-80 Metric Standard ALNslM Series | H=0.8D

Stainless Steel 316 A4-80 Metric Standard ALNsM Series | H=1D

Stainless Steel 316 A4-80 Metric Standard ALNshM Series | H=1.3D

How to define the difference between Type 304 and Type 316 stainless steel, explained.

Type Stainless Steel 304

  • Approximately 18% chromium and 8% nickel
  • Material specified more than 50% of the time whenever a stainless steel is used
How to, Why / Where Used:
  • Ease of cleaning, ease of fabrication, beauty of appearance
  • Excellent in a wide range of atmospheric environments
  • Corrosion/ oxidation resistance due to the chromium content
  • Food Processing – Breweries

Type Stainless Steel 316


  • Approximately 16% chromium, 12% nickel, 3% Molybdenum
  • “Moly” increases resistance to withstand attack by many industrial chemicals and solvents and in particular, inhibits pitting caused by chlorides

How to, Why / Where Used:

  • Where the possibility of severe corrosion exists
  • Pulp & Paper – Marine Environments – Wastewater Treatment

Stainless steel 316 A2 and A4 provides a highly reliable, durable conduit that ensures uptime , increases productivity and provides a long service life in industrial and commercial applications. In short, stainless 316L steel offers significant cost savings over alternative conduit and fittings.


  • Made from 316L stainless steel or ss316 for increased corrosion resistance in a variety of applications.
  • A4 has a stronger corrosion resistance than A2 in aggressive conditions.
  • Resists to sulfur dioxide.
  • Resists to high chloride environments.

Industries Commonly Served

  • Food & Beverage Production
  • Marine & Coastal Facilities
  • Chemical Plants
  • Water & Wastewater Treatment
  • Pharmaceuticals & Cosmetics
  • Refining & Extraction Sites
  • Petrochemical Operations
  • Pulp & Paper Mills
  • Along with other corrosive environments