Can You Convert Allis-Chalmers HD6 Tracks to Fit an IH Dresser Dozer

[MikePhua]

The Legacy of Allis-Chalmers and International Harvester in Crawler Design
Allis-Chalmers and International Harvester were two titans of mid-20th-century American machinery. The HD6, introduced by Allis-Chalmers in the 1940s, was a compact crawler dozer powered by a 344 cubic inch diesel engine. It became a staple in road building, logging, and farm work. Meanwhile, International Harvester’s TD-series crawlers—later branded as Dresser after the 1985 merger—dominated the utility and construction sectors with their rugged undercarriages and modular design.
Both companies built their machines with proprietary track systems, but over time, parts interchangeability became a practical necessity for owners maintaining aging fleets. The HD6 and IH/Dresser dozers share similar weight classes and track widths, making conversion a tempting proposition.
Terminology Annotation

• Track Chain Pitch: The distance between pin centers in a track chain, critical for sprocket compatibility.
  
• Shoe Width: The width of the track pad, affecting flotation and frame clearance.
  
• Bushing Diameter: The outer diameter of the track bushing, which must match the sprocket teeth profile.
  
• Carrier Rollers: Upper rollers that support the track chain and maintain alignment.
  

Evaluating Compatibility Between HD6 and IH/Dresser Tracks
Converting HD6 tracks to fit an IH Dresser dozer requires careful measurement and mechanical adaptation. Key compatibility factors include:

• Pitch Matching: HD6 chains typically use a 6.75-inch pitch, while Dresser dozers may vary between 6.75 and 7 inches depending on model. A mismatch will cause sprocket wear and derailment.
  
• Sprocket Profile: The tooth spacing and depth must match the bushing diameter and link spacing. Modifying sprockets may be necessary.
  
• Track Frame Clearance: Wider shoes from the HD6 may interfere with guards or roller mounts on the Dresser chassis.
  
• Roller Alignment: The roller spacing must match the link spacing to prevent uneven wear and derailment.
  

Anecdote from a Restoration Crew
In 2011, a restoration team in Oregon attempted to fit HD6 tracks onto a Dresser TD8E. After discovering a 0.25-inch pitch mismatch, they machined custom sprockets and added shims to the carrier rollers. The conversion succeeded, but required over 40 hours of labor and $1,200 in machining costs. The team later advised others to measure all components before committing to a swap.
Recommended Conversion Steps

• Measure pitch, bushing diameter, and shoe width on both track sets
  
• Compare sprocket profiles and determine if machining or replacement is needed
  
• Inspect roller spacing and modify mounts if necessary
  
• Check recoil spring travel to ensure proper chain tension
  
• Use hardened shims or spacers to adjust alignment
  
• Test-fit one side before committing to full conversion
  

Preventative Maintenance After Conversion
Once the tracks are installed:

• Monitor sprocket wear weekly for signs of misalignment
  
• Grease all rollers and idlers every 50 hours
  
• Re-torque shoe bolts after initial 10 hours of operation
  
• Inspect chain tension and adjust recoil springs monthly
  
• Keep spare bushings and pins on hand for field repairs
  

Design Reflections and Historical Context
The HD6 and Dresser dozers were built in an era of mechanical simplicity and field serviceability. While their track systems were proprietary, many owners have found ways to adapt components across brands. This reflects a broader trend in vintage equipment restoration, where ingenuity and fabrication replace factory support.
In the 1970s and 80s, parts interchangeability was rare. But today, with many OEMs defunct or consolidated, cross-brand adaptation has become a practical solution. Restoration shops often fabricate adapter kits or machine custom sprockets to keep legacy machines running.
Conclusion
Converting Allis-Chalmers HD6 tracks to fit an IH Dresser dozer is possible, but requires precise measurement, mechanical adaptation, and a willingness to fabricate. While not a plug-and-play swap, the conversion can extend the life of aging machines and reduce downtime. For owners committed to preserving mid-century iron, such projects are part of the legacy—where craftsmanship meets necessity in the dirt.