Self-Locking Counter Nuts are used primarily for a thin spring-steel counter nut tightened on top of a regular nut to lock it. This page lists the industries and assemblies where they are specified, the selection criteria that matter for each application, installation practice, and the cases where a different fastener type is the correct choice. Parts are supplied to DIN 7967. Stocked across roughly M4 to M52, they cover general to heavy-duty work.
Typical Applications for Self-Locking Counter Nuts
The most common settings where these are specified:
- Agricultural machinery: locking nuts on vibrating frames.
- Sheet-metal work: light locking where space is short.
- HVAC: fan and motor mounts.
- Transport: brackets subject to vibration.
How to Specify Self-Locking Counter Nuts for Your Application
- Size: Match the nominal size to the mating thread or hole. This product spans M4–M52; check the full table below for the exact dimensions of each size.
- Locking & grade: Match the strength grade to the bolt, and choose a locking style (nyloc, all-metal, serrated flange) if the joint sees vibration.
- Environment: For damp, coastal or chemical exposure prefer A4/316 stainless or a suitable coating; indoors, plated steel or A2 is usually sufficient.
- Standard: This product is supplied to DIN 7967. Quoting the standard on your order guarantees interchangeable dimensions between suppliers.
Installation & Assembly Practice
- Run the nut down by hand before applying the wrench to catch cross-threading early.
- Tighten the nut rather than the bolt head where access allows — the torque-to-preload relation is more consistent.
- For locking styles, note that nyloc inserts are single-use in critical joints and lose grip above roughly 120 °C.
Common Selection Mistakes with Self-Locking Counter Nuts
- Pairing a high-class bolt with a lower-class nut — the nut strips before the bolt reaches proof load; the nut class must meet or exceed the bolt class.
- Using a plain nut with a spring washer in severe vibration instead of a prevailing-torque locking nut.
- Re-using nyloc nuts in critical joints.
Where Self-Locking Counter Nuts Are Not the Right Choice
Not on their own — they need a matching bolt or stud — and a plain nut is not a substitute for a locking type under heavy vibration.
Custom manufacturing · Made to drawing
Need a self-locking counter nuts outside the standard range?
Locking method is specifiable independently of the rest: nylon insert, all-metal deformed thread, serrated flange, or none. Made by cold heading or tapping.
Minimum order from 2,000 pieces; samples within 7 days of drawing approval.
