Iscar 3398121 Corner Radius End Mill 1/4 in 4 Flute Carbide

Product Description

The ISCAR 3398121 is a solid carbide corner radius end mill engineered for demanding metal removal in roughing and finishing operations. It carries a 1/4-inch diameter, a 3/8-inch length of cut, and a 0.06-inch corner radius. The AlTiCrSiN PVD coating provides elevated heat and wear resistance, making it well suited for aggressive cutting in steel, stainless steel, cast iron, superalloys, and titanium. The submicron carbide grade and variable index geometry help reduce chatter and extend tool life in difficult materials. This is a single-end, centercutting tool with right-hand flute direction and right-hand cutting direction.

This end mill is designed for use in CNC machining centers and milling fixtures where tight tolerances and surface finish matter across a range of ferrous and exotic alloys. The extended-reach configuration and short flute length make it practical for profiling, contouring, and slotting operations where radial loads must be managed carefully. It mounts in a standard straight-bore toolholder and is appropriate for job shops, production shops, and tool rooms running ISO material groups P, M, K, S, and H. It is part of the ECI-4-VF series and corresponds to catalog number ECI-4 250-375C06VF2.

Key Features

• Solid submicron carbide construction for rigidity and wear resistance in hard and abrasive materials
• AlTiCrSiN PVD coating rated for steel, stainless steel, cast iron, superalloys, titanium, and hard materials
• 0.06-inch corner radius reduces stress concentration and improves edge strength at workpiece corners
• Variable index geometry minimizes harmonic vibration during roughing and finishing passes
• Centercutting design allows plunge entry without a pre-drilled pilot hole
• Straight-cylindrical shank with h6 tolerance for precise, repeatable toolholder fit

Compatibility

Designed for use with standard straight-bore toolholders accepting a 1/4-inch shank. Suitable for ISO workpiece material groups P (steel), M (stainless steel), K (cast iron), S (superalloys and titanium), and H (hard materials) as specified by the manufacturer.

Installation Notes

Installation and tool changes must be performed with the machine spindle fully stopped and all motion axes at rest. Secure the shank in a clean, undamaged toolholder bore and tighten to the toolholder manufacturer's specified procedure. Inspect the corner radius and cutting edges for chips or damage before mounting. Confirm runout is within acceptable limits before initiating any cut, as excessive runout accelerates edge wear and can compromise workpiece finish.