Corner Radius End Mills — Catalog by Size and Manufacturer

Compiled 2026-04-04 · 40 chunks, 15 posts · endmills · corner-radius · tooling-catalog · carbide · milling

Summary

Corner radius end mills feature rounded cutting edges instead of sharp 90° corners, providing superior surface finish, extended tool life, and reduced [[chatter-vibration]] in [[profiling]] and contouring operations. The radius distributes cutting forces more evenly, preventing edge chipping and enabling higher feed rates. Available in radii from 0.2mm to 12.5mm, these tools are essential for finishing operations in molds, dies, and precision components requiring smooth surface transitions.

Corner Radius Selection Guide

Small Radius (0.2-2.0mm): Use for finishing operations requiring tight corner definition. Typical applications include mold inserts, precision fixtures, and aerospace components.

Medium Radius (2.0-6.0mm): General-purpose finishing for most applications. Provides good balance between tool strength and surface finish quality.

Large Radius (6.0-12.5mm): Heavy-duty applications requiring maximum tool strength. Ideal for roughing-to-finish operations and high-material-removal-rate profiling.

Manufacturer Catalog by Size

Small Diameter Tools (Under 12mm)

Iscar MM Series - Fine Radius

  • EC080B05R0.4-3T08: 8mm dia, 0.4mm radius, 3-flute
  • EC120B09R0.5-4T08: 12mm dia, 0.5mm radius, 4-flute
  • EC120B09R0.5-6T08: 12mm dia, 0.5mm radius, 6-flute (high feed)
  • EA120H12R0.2CF-3T08: 12mm dia, 0.2mm radius, 3-flute

Harvey Tool Small Radius Series

  • 45947/45947-C3: 0.25" dia, 4-flute, uncoated/AlTiN
  • 45962/45962-C3: 0.375" dia, 4-flute, uncoated/AlTiN
  • 781393-C3: 0.093" dia, 4-flute, AlTiN (micro-machining)

Medium Diameter Tools (12-20mm)

Iscar MM Series - Standard Radius

  • EB120A09-4T08: 12mm dia, 5.98mm radius, 4-flute
  • EB160A12-4T10: 16mm dia, 7.98mm radius, 4-flute
  • EBC160B12-4T10CF: 16mm dia, 7.98mm radius, coated

Sandvik MS20 Series

  • MS20-R016A16L-10L: 16mm dia, long reach
  • MS20-R018A16L-10L: 18mm dia, long reach
  • MS20-R020A20-10M: 20mm dia, medium length

Large Diameter Tools (20mm+)

Iscar MM Series - Heavy Duty

  • EB200A15-4T12: 20mm dia, 9.97mm radius, 4-flute
  • EBC200B15-4T12CF: 20mm dia, 9.97mm radius, coated
  • EB250A22-4T15: 25mm dia, 12.47mm radius, 4-flute

Sandvik MS20/MS20D Series

  • MS20-R025A25-10L: 25mm dia, long length
  • MS20D-R032A32-10L: 32mm dia, double-sided inserts
  • BCM D25-MMT15-C: 25mm dia, 12.5mm radius, 57mm OAL

Speeds and Feeds by Material

[[aluminum-6061]]

  • SFM: 800-1500 (manufacturers recommend 600-1000, but experienced machinists push 1200-1500)
  • Feed per tooth: 0.003-0.008" (start at 0.004")
  • Axial depth: 0.5-1.0 × diameter
  • Radial depth: 10-40% diameter for finishing

[[4140-steel]] (Hardness 28-32 HRC)

  • SFM: 300-600 (carbide), 150-250 (HSS)
  • Feed per tooth: 0.002-0.005"
  • Axial depth: 0.25-0.5 × diameter
  • Radial depth: 5-25% diameter

[[304-stainless]]

  • SFM: 250-450
  • Feed per tooth: 0.003-0.006" (keep feeds up to prevent [[work-hardening]])
  • Axial depth: 0.3-0.6 × diameter
  • Radial depth: 8-30% diameter

[[titanium-ti6al4v]]

  • SFM: 200-350
  • Feed per tooth: 0.002-0.004"
  • Axial depth: 0.2-0.4 × diameter
  • Radial depth: 5-20% diameter

Flute Count Selection

2-Flute: Maximum chip evacuation, soft materials, deep slotting 3-Flute: Balance of strength and chip clearance, general purpose 4-Flute: Better surface finish, harder materials, shorter tools 6+ Flute: High-feed applications, finishing passes only

Coating Recommendations

AlTiN (Harvey -C3, Iscar CF): General purpose, good for steel and stainless TiAlN: High-temperature applications, titanium and inconel Uncoated: Aluminum and non-ferrous metals (prevents built-up edge) Diamond-like Carbon: Graphite, composites, abrasive materials

Common Problems and Solutions

Poor Surface Finish

  • Increase corner radius size for stronger cutting edge
  • Reduce feed rate and increase spindle speed
  • Check for insufficient rigidity causing [[chatter-vibration]]
  • Verify proper coolant flow to corner radius area

Premature Corner Wear

  • Corner radius too small for application
  • Excessive radial engagement
  • Wrong coating selection for material
  • Insufficient corner radius engagement (running on sharp edge)

Edge Chipping

  • Reduce feed rate on entry/exit
  • Use climb milling when possible
  • Check for workpiece movement
  • Consider larger corner radius for more robust edge

Shop Floor Tips

Corner Radius Measurement: Use radius gauges or optical comparator to verify actual radius matches part number. Manufacturing tolerances can vary ±0.05mm.

Programming Considerations: CAM systems often don't account for corner radius in toolpath calculation. Add 50-75% of radius value to stock allowance for finishing passes.

Tool Life Extension: Run corner radius tools at 80% of manufacturer's recommended feed rate for 2-3× longer tool life. The radius distributes wear over larger area.

Workholding: Corner radius end mills generate different cutting forces than sharp tools. Expect more upward pull and lateral forces during side milling operations.

Inspection: Corner radius tools leave characteristic "orange peel" texture at very light feeds. This is normal - increase feed rate to 0.003" minimum per tooth to eliminate.

Insert Compatibility: Some manufacturers offer same corner radius in solid carbide and indexable versions. Sandvik MS20D series uses same geometry as solid tools for consistent part dimensions.

  • [[endmill-types]] — Overview of end mill geometries and applications
  • [[surface-finish-problems]] — Troubleshooting poor finishes in milling
  • [[chatter-vibration]] — Reducing vibration with proper tool selection
  • [[tool-wear-diagnosis]] — Identifying wear patterns on corner radius tools
  • [[aluminum-6061]] — Specific parameters for aluminum machining
  • [[profiling]] — Contouring and 3D surfacing operations
  • [[toolholder-selection]] — Proper holders for corner radius end mills