The ATC 30121 Headbolt Thread Chasing Tap is a high-precision tool engineered for the Detroit Diesel 60 / 50 Series engines. Specifically, it restores or cleans the M16 × 2.0 headbolt threads in cylinder block headbolt holes, removing corrosion, carbon deposits, nicks, or minor damage to ensure proper bolt engagement and sealing.
Regular use of the ATC 30121 ensures that reinstalled headbolts seat accurately, achieve consistent torque, and reduce risks of head gasket leaks or bolt failure during reassembly. This tap is ideal for engine rebuilders, diesel shops, and maintenance facilities working on Detroit Diesel 50/60 and 60-series commerce engines.
Key Features & Benefits
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Correct M16-2.0 UNF size for Detroit Diesel 60 / 50 series headbolt holes
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Precision ground to chase threads without overcutting
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Restores worn or damaged bolt holes for consistent torque application
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Durable for shop usage, rebuild operations, and engine overhauls
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Helps improve head gasket integrity and reduces rework
Made in USA
Applications & Use Cases
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Preparing headbolt holes during engine teardown or rebuild
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Cleaning threads to remove deposits, rust, or burrs
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Ensuring headbolts reengage properly during head installation
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Used in Detroit Diesel 50/60 / 60 Series engines, especially where M16-20 headbolt threads are used
