Sandvik Coromant 7859107 Turning Insert DCMT21.51-UM

Product Description

The SANDVIK COROMANT 7859107 is a solid carbide turning insert designed for precision external and internal turning operations. Designated DCMT21.51-UM 4415, it carries a CVD-applied multilayer coating of TiCN, Al2O3, and TiN that provides wear resistance and thermal stability across a range of cutting conditions. The 55-degree diamond insert shape (shape code D) delivers a sharp, stable cutting geometry suited to profiling and general turning. With a 0.4 mm (0.0156 inch) corner radius, a 1/4-inch inscribed circle, and a UM chip breaker geometry, this insert is optimized for steel as the primary workpiece material and cast iron as the secondary. Neutral hand orientation allows flexible application on standard toolholders.

This insert is engineered for use on CNC lathes and turning centers in both production and job-shop environments. The CoroTurn 107 series is applied in light-to-medium turning of steel and cast iron components where consistent chip control and surface finish are critical. It fits toolholders accepting DCMT-style inserts with clamp or screw holding methods. The ISO designation DCMT 07 02 04-UM 4415 provides direct cross-reference for toolholder selection. Typical applications include shoulder turning, profiling passes, and finishing cuts where the 55-degree geometry provides adequate clearance.

Key Features

• CVD multilayer coating: TiCN, Al2O3, and TiN for thermal barrier and crater-wear resistance
• 55-degree diamond insert shape with 7-degree relief angle (clearance code C)
• 0.4 mm corner radius suited to finishing and light profiling cuts
• UM chip breaker geometry optimized for steel turning and chip control
• Two cutting edges per insert
• Accepts clamp or screw holding in compatible DCMT toolholders

Compatibility

Designed for use in SANDVIK COROMANT CoroTurn 107 series toolholders accepting DCMT-style inserts. ISO designation DCMT 07 02 04-UM 4415 and manufacturers catalog number DCMT 2(1.5)1-UM 4415 provide toolholder cross-reference. Compatible holding methods include clamp and screw styles.

Installation Notes

Insert replacement and toolholder seating should be performed by a qualified machinist with machine power and spindle fully locked out before servicing. Seat the insert firmly against all toolholder contact surfaces and verify clamping torque per the toolholder manufacturer specification. Inspect the insert pocket and clamping hardware for wear or debris before indexing to the second cutting edge. Follow the toolholder manufacturer guidelines for insert indexing sequence to avoid premature edge damage.