Self-locking stainless steel washers for MZ34 head bolts


Steel lock washers that work!

8 sets (16 total pieces) auto locking lock washers for Metric (M6) MZ34 head bolts.

Tired of your head bolts on your MZ 313 always vibrating loose? Our lock washers off a superior bolt securing system that does not use traditional techniques to secure the fastener, and yet still provides a safe locking system for bolted joints even when exposed to severe vibration, heat and dynamic loads.

The bolt-securing system is comprised of special cam faced washers; in order to facilitate assembly they come pre-assembled in pairs (glued). They are ELV and RoHS compliant.

Our washers are made of EN 1.7182 alloy and are through hardened.

 The Locking Function

The Locking Function

The lock washer securing system uses geometry to safely lock bolted joints in the most critical applications. Tension makes the bolt self-locking; the key is the difference in angles. Since the cam angle " a " is larger than the thread pitch " ß ", the pair of washers expands more than the corresponding pitch of the thread. Any attempt from the bolt/nut to rotate loose is blocked by the wedge effect of the cams. They will positively lock the fastener in a joint that is subjected to extreme vibration or dynamic loads.

This unique wedge-locking system offers the following advantages:

  • Maximum safety
  • Resists loosening caused by vibration and dynamic loads
  • Ease of assembly and disassembly
  • Locking function is not affected by lubrication
  • Positive locking at low and high preload levels
  • Controllable preload
  • Same temperature characteristics as standard bolt/nut
  • Reusable

The Truth: The Junker Test Principle

For testing and comparing the security of bolted joints, a Junker vibration test meeting DIN 65151 is an excellent method. In a Junker test the bolted joint is subjected to transverse movements while a load cell is continuously measuring the tension.

The Junker Test

The diagram displays their superior performance. Most of the commonly used locking devices show limited or no holding performance when exposed to vibration. Whereas bolted joints secured with lock washer system only lose some of the initial preload due to normal settlements between the contact surfaces. The unique wedge-locking function is proved by the clear increase in clamp load during untightening.

Vibration Test Results

  • Model: Self lock MZ34 head bolt washers

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