Accupro 311491 Square End Mill 5/16in 5 Flute Solid Carbide

Product Description

The ACCUPRO 311491 is a solid carbide square end mill engineered for precision milling in demanding metal-cutting applications. Built from micrograin carbide stock, it delivers the hardness and edge retention needed for high-performance finishing and semi-finishing passes. The 5/16 inch diameter cutter runs five flutes with a 38-degree helix angle and variable index spacing, reducing harmonic chatter during the cut. An AlTiCrN coating adds thermal resistance and surface hardness, extending tool life in abrasive and high-heat cutting environments. This is a single-end, center-cutting tool installed and operated by machinists and tool-and-die professionals on CNC mills and manual knee mills.

The 311491 is suited for milling slots, pockets, and profiles in ferrous and non-ferrous workpiece materials where a 5/16 inch cutter diameter is specified. The 13/16 inch length of cut accommodates moderate-depth passes without excessive deflection. The right-hand cut and right-hand flute spiral are standard for conventional CNC spindle rotation. With a 5/16 inch straight shank diameter matching the cutter diameter, it seats in standard ER collets, end mill holders, and shrink-fit tooling of the appropriate bore size. The 2-1/2 inch overall length suits most standard tool-length offsets on vertical machining centers.

Key Features

• 5 flutes with variable index spacing reduce vibration and chatter at higher feed rates
• 38-degree helix angle promotes efficient chip evacuation and smooth cutting action
• AlTiCrN coating provides high thermal resistance for extended tool life in hard and abrasive materials
• Micrograin solid carbide substrate delivers superior hardness and edge retention versus HSS
• Center-cutting geometry allows plunge entry directly into the workpiece
• Single-end design with right-hand cut and right-hand spiral for standard CNC spindle compatibility

Compatibility

Designed as a direct-fit replacement or standard tooling selection for CNC machining centers and manual mills accepting a 5/16 inch shank in ER collets, end mill holders, or shrink-fit toolholders of matching bore. Part of the ACCUPRO HS Series solid carbide end mill line.

Installation Notes

Installation is performed by a machinist or CNC setup technician. Ensure the machine spindle is fully stopped and the tool changer or spindle is locked out before inserting or removing the end mill. Seat the shank to the recommended gauge-line depth in the toolholder and torque the collet nut or set screw per the toolholder manufacturer specification. Verify tool runout with a dial indicator before beginning the cut, as excessive runout accelerates flute wear and reduces surface finish quality.