Sandvik Coromant 7861072 Turning Insert VBMT331-PM 4425

Product Description

The SANDVIK COROMANT 7861072 is a VBMT-style turning insert in the CoroTurn 107 series, designed for external turning operations on CNC lathes and turning centers. It is manufactured from solid carbide with a CVD-applied multilayer coating consisting of Al2O3, TiN, and TiCN, which provides thermal resistance and wear protection during continuous and light interrupted cuts. The insert features a 35-degree diamond shape, a 3/8-inch inscribed circle, and a 0.40 mm corner radius. It carries a neutral hand orientation and uses the PM chip breaker geometry. Licensed machinists and CNC operators install this insert type in production turning environments.

This insert is suited for turning steel and cast iron workpieces in both roughing and finishing passes where controlled chip formation is required. The PM chip breaker is engineered for medium machining of steel, offering reliable chip evacuation at moderate feed rates and depths of cut. It is appropriate for residential machine shops, job shops, and production facilities running medium-to-high volume turning cycles. The CoroTurn 107 series is designed for positive-rake toolholders accepting VBMT-style inserts with a 3/8-inch inscribed circle and a clamp or screw holding method.

Key Features

• CVD multilayer coating: Al2O3, TiN, and TiCN for extended tool life in steel and cast iron applications
• 35-degree diamond insert shape (Shape Code V) for access in tight turning profiles
• PM chip breaker geometry optimized for medium turning of steel workpieces
• 0.40 mm corner radius for balanced edge strength and surface finish
• Two cutting edges per insert, neutral hand orientation
• Manufacturer Grade 4425, ISO Code VBMT 16 04 04-PM 4425

Compatibility

Designed for use in CoroTurn 107 series positive-rake toolholders accepting VBMT-style inserts with a 3/8-inch inscribed circle, clamp or screw holding method, and a B clearance code with M tolerance. Primary workpiece material is steel (ISO Code P); secondary workpiece material is cast iron (ISO Code K).

Installation Notes

CNC machinists and toolroom technicians install turning inserts of this type. Power down and lock out the machine spindle before seating or replacing the insert. Use the correct torque driver for the clamping screw to avoid insert movement or edge chipping during the cut. Inspect the insert pocket and seating surface for debris or wear before installation to ensure proper insert contact and runout.