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Durlok® Self-Locking Washer, M12 Bolt, 13.10mm ID, 19.7mm OD, 1.35mm Thick, Alloy Steel, Zinc Flake

Unbrako Part No. 550256


Item Durlok Wedge-Lock Washer
System of Measurement Metric
Size 12mm
Inside Diameter 13.1
Outside Diameter 19.7
For Bolt Size M12
Material Alloy Steel
Hardness 47-52 HRC
Finish Zinc Flake
Standard SAE 4130


The Durlok® locking wedge washer when used in combination with standard hex helps achieve self-locking properties. It is an anti-vibration solution that not only prevents bolted joint failure, but also enables the bolted joint to retain its pre-load, thus reducing maintenance requirements. Durlok® washers come pre-assembled in pairs. They have wedge faces on the inside and radial teeth on the outside. They are designed such that the wedge angle is greater than the thread angle. When the screw or the nut is tightened the radial teeth of Durlok washer locks itself onto the surface, allowing movement only across the wedge faces.

  • Designed for use with standard hex bolts & nuts, the Durlok® washers are always used in pairs.
  • Will not loosen or unscrew even under the most severe transverse jarring and vibration.
  • Reusability is guaranteed with locking ability maintained.
  • Durlok® washers must not be used with other flat washers.

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