Track Press Jig Design and Tooling for Undercarriage Rebuilds

[MikePhua]

The Role of Track Presses in Heavy Equipment Maintenance
Track presses are essential tools in the maintenance of crawler-type machinery, including excavators, bulldozers, and track loaders. These machines rely on steel track chains composed of links, bushings, and pins that wear over time due to friction, impact, and environmental exposure. Replacing or rebuilding track chains requires high-force pressing equipment capable of disassembling and reassembling components with precision.
A track press typically applies between 100 and 300 tons of hydraulic force to remove or install pins and bushings. The jig—the fixture that holds the track in place—is the heart of this operation. It must be rigid, modular, and adaptable to various track sizes and configurations. Without a properly designed jig, the press cannot deliver force evenly, risking damage to components or injury to technicians.
Jig Design Fundamentals and Material Selection
An effective track press jig includes several key elements:

• Base frame constructed from high-strength steel I-beams or box tubing
  
• Adjustable saddles or cradles to support track links
  
• Removable side plates to accommodate different chain widths
  
• Pin alignment guides to ensure axial force application
  
• Safety shields or deflection guards to contain debris
  

The jig must resist torsional flexing under load. For example, a 200-ton press exerts approximately 400,000 pounds of force. If the jig deflects even 1 mm under load, it can misalign the pin and cause galling or fracture. Engineers often use ASTM A572 Grade 50 steel for jig frames due to its yield strength of 50 ksi and good weldability.
Tooling Variants and Custom Adaptations
Tooling refers to the press attachments that interface with the track components. Common tooling includes:

• Pin pushers with hardened steel tips
  
• Bushing extractors shaped to grip outer diameters
  
• Spacer blocks to isolate specific links
  
• Hydraulic return cylinders for controlled retraction
  

Some shops fabricate custom tooling for unusual track designs, such as offset bushings or sealed link assemblies. In one case, a forestry contractor in British Columbia modified a standard jig to accommodate a Komatsu D65PX track chain with oversized bushings. They used CNC-milled aluminum inserts to reduce weight and improve handling during winter rebuilds.
Terminology Notes

• Galling: A form of wear caused by adhesion between sliding surfaces, often resulting in material transfer and surface damage.
  
• Yield Strength: The stress at which a material begins to deform plastically, beyond which permanent deformation occurs.
  
• Spacer Block: A rigid insert used to isolate or support components during pressing operations.
  
• Return Cylinder: A hydraulic actuator that retracts tooling after force application, improving cycle time and safety.
  

Safety Considerations and Force Distribution
Track presses operate under extreme pressure. Improper jig design or worn tooling can lead to catastrophic failure. Safety protocols include:

• Regular inspection of welds and fasteners
  
• Use of pressure-rated hydraulic hoses with burst protection
  
• Installation of emergency stop switches and pressure relief valves
  
• Operator training in force alignment and load path awareness
  

In 2021, a mining operation in South Africa experienced a press failure due to misaligned tooling. The pin ejected at high velocity, striking a technician’s leg and causing a compound fracture. Investigation revealed that the jig lacked lateral bracing, allowing the track to shift under load. Following the incident, the company redesigned its jig with cross-braced gussets and added laser alignment tools.
Modular Jig Systems and Portability
Modern workshops increasingly favor modular jig systems that can be reconfigured for different track types. These systems use bolt-on components, quick-release saddles, and telescoping frames. Benefits include:

• Reduced setup time
  
• Easier transport between job sites
  
• Compatibility with multiple press models
  

A rental fleet operator in Texas reported a 40% reduction in rebuild time after switching to a modular jig system. They could service Caterpillar, John Deere, and Hitachi track chains using the same base frame with interchangeable tooling.
Recommendations for Jig Fabrication and Use

• Design for at least 1.5x the maximum expected press force to ensure structural integrity
  
• Use hardened steel for contact surfaces to prevent deformation
  
• Include alignment pins and guides to maintain axial force direction
  
• Test jig under load with dummy components before live operation
  
• Maintain a log of press cycles and tooling wear for predictive maintenance
  

Historical Context and Industry Trends
Track presses have evolved from manual screw-type devices to fully hydraulic systems with programmable force profiles. In the 1970s, most undercarriage rebuilds were performed by OEM dealers. Today, independent shops and contractors perform over 60% of track chain servicing, driven by the availability of aftermarket parts and portable press systems.
Jig design has followed suit, becoming more user-friendly and adaptable. CAD modeling and finite element analysis (FEA) allow engineers to simulate stress distribution before fabrication. As equipment sizes diversify—from mini excavators to 100-ton mining crawlers—jig versatility becomes a competitive advantage.
Conclusion
A well-designed track press jig is essential for safe, efficient undercarriage rebuilds. By understanding the mechanical forces involved, selecting appropriate materials, and incorporating modular tooling, technicians can service a wide range of track chains with confidence. As the industry continues to decentralize maintenance operations, jig innovation will play a key role in productivity and safety. Whether fabricating in-house or sourcing commercially, investing in robust jig systems is a strategic move for any heavy equipment operation.