Corner Radius End Mills

AIMS Industrial sells corner radius end mills — also known as bullnose end mills — for CNC machining centres and manual milling where sharp internal corners need radiusing to reduce stress concentration and improve fatigue life. Our solid carbide and HSS range from Sutton Tools covers corner radii from 0.5 mm to 6 mm in diameters from 4 mm to 25 mm.

Corner Radius End Mill Advantages

• Reduced stress concentration: A corner radius distributes cutting load across a larger edge area, reducing edge chipping — particularly important in hardened steel machining.
• Longer tool life: Corner radii of 5–15% of tool diameter improve tool life by 2–4× compared to sharp-cornered end mills in identical conditions.
• Improved surface finish: The radiused corner produces a smoother blend between floor and wall in pockets and slots — reducing hand finishing time in moulds and dies.
• Stronger cutting edge: Greater cross-sectional area at the corner supports higher cutting forces — allows higher feed rates in roughing and semi-finishing operations.
• Design compatibility: Many engineering drawings specify minimum internal corner radii for stress and fit reasons — corner radius end mills machine to these specifications directly.

Selection Considerations

• Corner radius vs tool diameter ratio: A 1 mm radius on a 6 mm end mill is a significant geometry change; the same 1 mm radius on a 16 mm mill has minimal effect on cutting performance.
• Material: Solid carbide corner radius end mills are preferred for hardened steel and finishing; HSS is adequate for aluminium and mild steel roughing.
• Flute count: 2-flute for aluminium (chip clearance); 4-flute for steel (rigidity and surface finish); 5–6 flute for fine finishing passes in hardened steel.
• Coating: TiAlN and AlTiN PVD coatings extend tool life 3–5× in hardened steel, stainless and high-temperature alloys — essential for production mould and die work.

Australian Business, Local Supply: As a proudly Australian business since 1988, we stock locally and work with trusted local Australian manufacturers and distributors to ensure fast, reliable supply.

Expert Support: Need help buying the right product for your application? Contact our team or request a quote for application-specific advice.

Also see our Hand Tools and Power Tool Accessories for complementary products.