Cast Component and Machine Repair

The Duny Group is a collection of companies that specialize in the manufacture of precision custom components. The three divisions are Duny Machine, Rudy’s Machine, and Herculock.

Herculock has been repairing cast iron and cast metal components for more than 75 years. As part of The Duny Group, Herculock maintains a strong focus on engineering, communication, and consistency. Our staff provides high-quality cast components and machine repair services for equipment in a broad range of industries and applications. These services extend the lifespan of aging and damaged components, significantly reducing the burden of expensive replacement parts and downtime.


At Herculock, we specialize in the repair of cast iron and cast metal components. We fix cracked or broken metal castings by securing the two disparate pieces of metal back together using a process called metal locking or metal stitching. Our cast component and machine repair services can benefit a variety of equipment.

A few examples of components we commonly repair include:

  • Casings, large and small
  • Crusher parts
  • Gearboxes
  • Housings
  • Stamping presses, frames etc.

Equipment and Process

The Herculock metal locking process repairs cracked or broken components without the need for heat, mitigating the need to buy expensive OEM replacement parts for critical machinery. The process typically goes as follows:

  • Irreparable damage is cut from the component on either side of the break.
  • Holes are drilled along the length of the fracture or split on each half of the broken casting.
  • These holes are worked out and connected to form slots.
  • Locking mechanisms are inserted into the slots to create a connection across the break.
  • Additional holes are then drilled and tapped along the crack between each locking mechanism.
  • Special lacing bolts are inserted into these holes to fill the cracked space.
  • Repaired areas are then worked smooth to surface or machined if required.
  • Once products are repaired, we perform additional testing to verify the efficacy of the repair. Dye penetrant testing and magnetic particle inspection both play a critical role in pinpointing and remedying product quality errors.

As a cold process, metal locking offers an ideal alternative to welding in applications where heat is not recommended.

Industries Served

Herculock offers cast component and machine repair services for parts spanning all industries. Virtually any organization using cast parts can benefit from the savings provided by our equipment repair services. Some of the industries we commonly serve include:

  • Manufacturing
  • Metal stamping
  • Mining
  • Paper mills
  • Ships
  • Steel mills

Value-Added Services

In some cases, the Herculock team can provide additional reinforcements to components during the repair process to further improve the strength of the repaired. We also provide additional on-site machining and inspection services when needed.

Cast Component and Machine Repair at The Duny Group

Herculock has been providing guaranteed cast component repair to the United States and Canada since 1944. Our facility is ISO certified, ensuring the quality of our custom repairs. Our ability to repair cast components can save your operation significant replacement costs and reduce equipment downtime.

For more information about cast component and machine repair from Herculock, please contact us and LET DUNY DO IT!

Have a Cast Component and Machine Repair?

Contact Herculock!