how to calculate cutting speed from SFM. Get instant Pitch Dia (mm), Outside Dia (mm), Root Dia (mm), Base Dia (mm) for your machining parameters.
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Request a Proposal →Even with high-end tooling from Dormer Pramet and Tungaloy, things go wrong. Here are the most common Gear Parameters-related issues our technical team sees, and how to fix them.
Diagnosis: Your surface speed is likely too high. Even Dormer Pramet AlTiN-coated carbide can't outrun excessive heat generation. Check that your Gear Parameters matches the actual material hardness — a shift from HRC 28 to HRC 32 4140 changes everything.
Fix: Reduce SFM by 15-20%. Verify coolant concentration with a Tesa refractometer (target 8-10% for steel).
Diagnosis: Your Gear Parameters might be fine for straight cuts, but corner engagement increases dramatically. Tungaloy application engineers call this the "corner trap" — the tool sees 180° of engagement in a 90° internal corner.
Fix: Add a finish pass at 0.1mm radial depth with a separate finishing tool. Program the Haas to reduce feed rate to 50% in corners.
Diagnosis: You're applying Dormer Pramet Gear Parameters values to Tungaloy tools — or vice versa. Each manufacturer's carbide substrate and coating system has a different sweet spot.
Fix: Download the specific Gear Parameters chart for your exact tool from the manufacturer's website. Dormer Pramet CoroPlus and Tungaloy NOVO both offer free digital tools.
Spur gear dimensions are determined by the module (metric) or diametral pitch (imperial) and the number of teeth. This calculator uses standard involute gear geometry for 20 deg pressure angle -- the most common in industrial gearing.
Module (m) is metric: m = pitch diameter / number of teeth (mm). DP is imperial: DP = number of teeth / pitch diameter (inches). Conversion: module = 25.4 / DP. A DP 8 gear ≈ module 3.175. Metric gears are specified by module; imperial by DP.
20 deg is the modern standard (ISO 53, AGMA 201.02). Older machinery sometimes uses 14.5 deg (older AGMA standard). 25 deg is used for high-strength gears. The pressure angle affects tooth thickness, contact ratio, and the minimum number of teeth before undercutting.
Yes, with an involute gear cutter (form-milling) or by generating the profile via CNC hobbing cycles. Form-milling uses a cutter shaped like the tooth space. For one-off gears, 3+2 axis milling with a ball end mill can approximate the involute profile.
Enter the module and number of teeth. The calculator gives all major spur gear dimensions per ISO 53 (20 deg pressure angle). Use these values for gear blank turning, gear cutting setup, and over-pin inspection measurements.
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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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