Seco 03310378 Turning Insert DCMT21.51-M3 TP25 Carbide

Product Description

The SECO 03310378 is a solid carbide turning insert in the DCMT-M3 series, designed for precision metal cutting on CNC lathes and turning centers. It carries industry standard designation DCMT21.51-M3 and ISO code DCMT070204-M3. The insert features a multilayer CVD coating consisting of TiCN, Al2O3, and Cr, which provides thermal resistance and wear protection during extended cutting cycles. The M3 chip breaker geometry uses a chamfered and honed cutting edge with a positive rake angle of 17 degrees, making it well-suited for finishing and semi-finishing operations. Holding is accomplished via screw clamp. Each insert delivers two usable cutting edges.

This insert is rated for primary use on steel workpieces (ISO P-class, material grades P20, P25, P30, and P35) and is also applicable to stainless steel (ISO M-class) and cast iron (ISO K-class). Typical applications include back turning, boring, facing, and general longitudinal turning on both manual and CNC lathes. It is sized for use in toolholders accepting DCMT-series inserts with a 1/4 inch inscribed circle. Licensed machinists, toolroom operators, and CNC setup technicians are the primary installers of this insert type.

Key Features

• Multilayer CVD coating (TiCN, Al2O3, Cr) for extended tool life in steel cutting
• 55-degree diamond insert shape with neutral hand orientation
• M3 chip breaker with positive rake geometry for controlled chip formation
• Chamfered and honed cutting edge style reduces edge micro-chipping
• Two cutting edges per insert for cost efficiency
• Screw-clamp holding method ensures repeatable seating and rigidity

Compatibility

Designed as a direct-fit replacement for DCMT-series toolholders accepting a 1/4 inch inscribed circle insert. Conforms to ANSI and ISO standards for DCMT insert geometry. Verified for use in applications involving steel, stainless steel, and cast iron workpieces.

Installation Notes

Installation should be performed by a qualified machinist or toolroom technician. Ensure the machine spindle is fully stopped and the toolholder is secured before seating or indexing the insert. Use the appropriate Torx or hex key to tighten the clamping screw to the toolholder manufacturer's specification; do not overtighten. Inspect the insert pocket and screw threads for chips or debris before each insert change.