Turning Inserts

Carbide turning inserts: how to choose the right one

INNOT turning inserts are ISO inserts in coated carbide and cermet for external and internal turning, profiling, parting and threading. Every product page lists sizes, nose radii, grades and recommended cutting data, so you can find the right insert for your material without trial and error.

Negative or positive?

Negative inserts (CNMG, DNMG, SNMG, TNMG, VNMG, WNMG) have a 0° clearance angle and are double-sided: they offer twice the cutting edges and a strong edge for roughing and heavy cuts. Positive inserts (CCMT, DCMT, SCMT, TCMT, VBMT, VCMT) have a 5° or 7° clearance: they cut with lower forces and are the right choice for finishing, small diameters, internal turning and thin-walled parts.

How to read the ISO code

In the code CNMG 120408, C is the shape (80° rhombic), N the clearance angle (0°), M the tolerance and G the insert type (hole and chipbreaker on both sides). Then come the cutting edge length (12), the thickness (04 = 4.76 mm) and the nose radius (08 = 0.8 mm).

Chipbreaker and grade

The chipbreaker decides how the chip forms and breaks: geometries for finishing (GF, GC, BF, SF), semi-finishing (GM, GQ, BM, SM) and roughing (GR, BR, GX, GZ). The carbide grade is chosen according to the ISO group of the material: P steel, M stainless steel, K cast iron, N aluminium, S superalloys and titanium, H hardened steel.