Iscar 3398070 Corner Radius End Mill 5/16 in 4 Flute Carbide

Product Description

The ISCAR 3398070 is a solid carbide corner radius end mill designed for high-performance milling in demanding metal-cutting applications. Part of the ECI-4-VF series, it features a 5/16-inch diameter, a 0.03-inch corner radius, and four flutes with a variable index geometry to reduce harmonic vibration and improve surface finish. The AlTiCrSiN PVD coating provides thermal resistance and wear protection, making this tool effective across a wide range of ferrous and exotic workpiece materials. At 2 inches overall length with a 1/2-inch length of cut, it is configured for short-reach, high-rigidity setups. Installed and operated by machinists and tool-and-die professionals on CNC milling equipment.

This end mill is suited for both roughing and finishing operations on steel, stainless steel, cast iron, superalloys, titanium, and hard materials. The extended-reach shank geometry and straight-cylindrical shank with h6 tolerance make it compatible with precision toolholders requiring tight runout control. The centercutting capability allows plunge entry, expanding its application to slot milling, pocket milling, and contour operations. It is particularly effective in short-chop and high-speed machining strategies where corner radius integrity and coating durability are critical.

Key Features

• AlTiCrSiN PVD coating for high heat resistance and extended tool life in hard and abrasive materials
• Variable index flute geometry reduces chatter and improves surface finish during aggressive cuts
• Centercutting design enables direct plunge entry without a pre-drilled pilot hole
• 0.03-inch corner radius reduces stress concentration and improves edge strength at workpiece corners
• Submicron carbide grade substrate provides toughness and wear resistance in interrupted and continuous cuts
• Right-hand cut and right-hand spiral flute direction for standard CNC milling spindle operation

Compatibility

Designed for use with standard precision toolholders accepting a 5/16-inch straight-cylindrical shank with h6 tolerance. Compatible with CNC machining centers and manual mills running on steel, stainless steel, cast iron, superalloys, titanium, and hard materials. Manufacturers catalog number ECI-4 312-500C03VF2 may be used for cross-reference.

Installation Notes

Installation should be performed by a qualified machinist following the toolholder manufacturer specifications for clamping torque and runout verification. Ensure the spindle is fully stopped and the machine is in an e-stop or locked-out state before inserting or removing the end mill. Verify tool projection and shank engagement depth meet the minimum requirements for the specific toolholder in use. Confirm cutting parameters — speed, feed, and depth of cut — are appropriate for the workpiece material and machine rigidity before initiating a cut.