Brand New CBN Inserts Enable Accelerated Machining for Hard Part Turning

Iwaki, February 2022 — Tungaloy has announced the introduction of two brand new TungCut CBN-tipped inserts: STH300-SR BXA10 and STH500-SR BXA10 for efficient finish turning of hardened steel parts.

CBN inserts used for the finish O.D. turning process of hardened steel parts are generally offered in standard ISO shapes. Since 2.4 mm (.094″) nose radius is the largest available of these standard inserts, shops must use a significantly reduced feed rate to achieve a high-quality surface finish, which limits cycle time improvement. Likewise, when machining the shaft surface located in between two close shoulders of larger diameters using standard ISO CBN inserts, shops customarily use two different turning tools just to avoid interferences with the workpiece shoulders.

TungCut CBN-tipped STH inserts provide the solution to these challenges with a completely new turning concept. In the shape of TungCut grooving insert, the new STH inserts perform finish-turning by feeding the insert sideways on the worked surface.

Its CBN cutting edge features a unique wiper geometry: the frontal edge features an arc wiper of large radius. This generates superior surface finish in straight-line turning applications, while also allowing increased feed rates of up to 1.5 mm (.060″) per revolution with up to 0.1 mm (.004″) d.o.c. The wiper on the side edges is also designed to provide improved surface quality during finish-facing operations.

In addition, Tungaloy’s unique WavyJoint technology creates a strong joint of the CBN tip and carbide insert base at larger contact areas. This not only enhances the brazing strength between the two parts but also promotes the dissipation of cutting heat built up during aggressive high feed machining, thus preventing the CBN tip from debrazing and insert failure.

STH inserts are interchangeable with other TungCut grooving inserts and can be used with the existing toolholders with a seat size of 3 or 5. Facing and I.D. turning is also possible with select toolholders.


Product information
No. 391S7-G (Metric)