solid carbide vs indexable end mills cost. Get instant Thread Percentage (%), Suggested Drill Size (mm) for your machining parameters.
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Request a Proposal →Not all tooling manufacturers publish their Thread Percentage the same way. While the underlying physics doesn't change, the recommended ranges, safety margins, and application guidance vary considerably across Nachi, Iscar, and Mitsubishi Materials. Understanding these differences helps you make better tooling decisions.
Takes a material-group-first approach with Platit-coated grades as default. Their application guides provide conservative starting values with wide adjustment bands. CoroPlus digital integration offers real-time Thread Percentage optimization via ToolGuide.
Known for aggressive starting parameters — particularly in steel and cast iron. NOVO digital platform auto-adjusts Thread Percentage based on tool path engagement. Often the go-to reference for high-feed applications.
Pioneers of multi-directional Thread Percentage — their IQ series inserts thrive in turning profiles where engagement angle shifts continuously. Application-specific grades for ISO P/M/K with narrow, optimized Thread Percentage windows.
Key takeaway: Always default to your specific tool supplier's Thread Percentage charts. The differences between Nachi, Iscar, and Mitsubishi Materials reflect different coating chemistries (Platit vs. in-house) and carbide substrate formulations. A Nachi parameter won't necessarily translate to a Iscar equivalent — even at the same ISO grade designation.
Thread percentage measures how much of the full theoretical thread depth is engaged after tapping. Higher percentages give stronger threads but require more tapping torque.
65-75% is standard for most applications. 50-60% is acceptable for low-stress fasteners and reduces tapping torque significantly. Over 80% rarely adds strength (the bolt fails before the thread strips above ~65%) but dramatically increases tap breakage risk.
Yes, but with diminishing returns. The difference in pull-out strength between 50% and 75% engagement is about 10-15%. Going from 75% to 100% adds less than 5% strength but doubles tapping torque and tap wear.
Use a micrometer or caliper on the drill, not the nominal size. A worn 6.8 mm drill might actually cut 6.9 mm, changing your thread percentage. For critical threads, measure the drilled hole with a pin gauge before tapping.
Enter your tap drill diameter, the thread major diameter, and pitch. The calculator shows the resulting thread engagement percentage and suggests an alternative drill size for the standard 75% target.
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Use the calculator freely. If the result points to a tooling or process problem, we can source the exact carbide tooling you need from vetted factories in China. Compare factory-direct pricing.
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