Durlok Self-Locking Fasteners — Unbrako Vibration-Proof System

Unbrako Durlok is a patented self-locking fastener system engineered to maintain clamp load under severe vibration, thermal cycling, and dynamic loading where conventional fasteners loosen and fail. The Durlok system comprises matching screws, nuts, and washers that work together to create a mechanical interference fit in the thread engagement zone, preventing loosening without adhesives, nylon inserts, or deformed threads. Available in metric sizes M6 through M20, Durlok screws are Grade 12.9 with 1,220 N/mm² minimum tensile strength — combining the strength of Unbrako premium socket screws with positive vibration resistance. Unlike chemical thread-locking compounds that degrade at high temperatures, Durlok maintains its locking function across the full operating temperature range and through unlimited assembly-disassembly cycles. The system is reusable — the locking feature does not diminish with repeated use, eliminating consumable thread-locker costs. Shri Narayan Machinery LLP supplies the complete Durlok range in Noida for vibration-critical applications in automotive, railway, and heavy machinery.