Promax 156-31424 Corner Radius End Mill 1/4 in 4 Flute

Product Description

The PROMAX 156-31424 is a single-end, centercutting corner radius end mill ground from micrograin solid carbide and finished with an AlTiN (aluminum titanium nitride) PVD coating. It carries a 0.25 inch cutting diameter, a 0.0200 inch corner radius, and a 0.375 inch length of cut in a short-length geometry with a 2 inch overall length. The 40-degree high-helix, 4-flute spiral configuration with variable index promotes aggressive chip evacuation and reduced chatter across both roughing and finishing passes. AlTiN coating adds thermal hardness at elevated cutting temperatures, making this tool well suited for high-speed dry or near-dry machining in demanding alloy groups.

The 156-31424 is designed for machining steel, stainless steel, superalloys, and titanium - material groups P, M, and S. The short flute length and rigid 0.25 inch straight-cylindrical shank pair well with close-tolerance toolholders used in vertical and horizontal machining centers running these materials. The centercutting geometry allows plunge entry, giving the machinist flexibility for slotting, profiling, and pocket-milling operations in a single setup without a pre-drilled pilot hole.

Key Features

• Solid micrograin carbide substrate provides rigidity and edge retention in hard and abrasive workpiece materials
• AlTiN PVD coating elevates heat resistance for high-speed cutting in steel, stainless steel, superalloys, and titanium
• 0.0200 inch corner radius reduces stress concentration at the cutting edge and extends tool life in interrupted cuts
• Variable index 4-flute design dampens harmonics and reduces chatter during aggressive material removal
• 40-degree high-helix spiral flutes promote efficient chip evacuation and lower cutting forces
• Centercutting construction enables direct plunge entry without a pre-drilled hole

Compatibility

Designed for use with standard straight-bore toolholders accepting a 0.25 inch cylindrical shank. Primary workpiece materials are steel, stainless steel, superalloys, and titanium (ISO material groups P, M, and S). Part of the PROMAX Series 156 corner radius end mill family.

Installation Notes

Secure the 0.25 inch shank in a clean, properly sized toolholder collet or end mill holder and verify runout before cutting. Confirm the machine spindle, toolholder, and workpiece fixturing meet the rigidity demands of high-helix carbide tooling in hard alloy materials. Follow the machine tool manufacturer and toolholder manufacturer guidelines for clamping torque and stick-out length. Inspect the cutting edges and corner radius for chipping or coating wear before reuse, particularly after runs in titanium or superalloy stock.