MACHUS Steel Locknuts

The next generation of the MS21042

The hardening and electrolytic plating processes used in manufacturing MS21042-4 locknuts has been found to cause formation of Hydrogen atoms that can lead to hydrogen embrittlement. The Aerospace industry has recognized that these Hydrogen Induced Cracks have lead to some catastrophic failures in real-world applications.

Sky Climber Fasteners has developed the MACHUS Steel Locknut as a direct replacement for the MS21042-4. Our patent-pending thread technology provides the locking strength necessary, without creating the conditions that lead to Hydrogen Induced Cracking.

The MACHUS Steel Locknut meets / exceeds all other requirements for the MS21042: it is certified to exceed NASM25027 15-cycle torque tests and meets 30,000 cycle vibration tests.

More importantly, we carry AS9100 rev D registration with Design Authority. That means we can not only provide this critical fastener for your aerospace and aircraft programs, but we can also help your company create a custom part number. With your own part number, you can control the design and the aftermarket supplies of your fastener.