Case Study: Crushing Equipment


A manufacturer of crushing equipment was producing a $500,000 machine that could be loaded with gravel, rock, and construction aggregate. The 2-ton metal plate back stop at the end of the load track is connected to large cylinders with a pivot joint. The pivot joint was held together with a 2” Nylon type Locknut. During regular operating, this assembly experiences extreme impact vibration. This nylon type locknut option proved to be an unreliable fastening solution. The nylon type locknut would frequently loosen during operation and the locking function was diminished if it was re-tightened. As a result the assembly had to be frequently inspected in the field and the nut had to be replaced. If the joint failed before the inspection, the machine would malfunction resulting in a safety risk, more than $20,000 in repair costs, and several weeks of downtime.


The manufacture of the crushing equipment improved the assembly with a superior fastening solution. The hydraulic cylinders are now connected to the metal plate with the 2" Heavy Hex Security Locknuts. After switching to the Security Locknut, field failure of this pivot joint have been completely eliminated and the manufacturer no longer recommends frequent field inspections. This simple fix saves the machine operators thousands of dollars per year and improved the
reputation of the manufacturer.


  • No incidents involving this bolted joint since switching to the Security Locknut 3 years ago
  • Improved product reputation; the machines reliably crush material into smaller pieces for transport, recycle, and reuse
  • Minimal extra manufacturing cost per machine to use the Security Locknut - $420
  • Reduced product liability and eliminated expensive repair claims

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