CCMT 120404 / CCMT 431, chip breaker BF, grade FM2533 — positive 80° rhombic turning insert.
1/2" inscribed circle, 3/16" thick, 1/64" corner radius. The BF breaker is the Finishing geometry: 0.002–0.008 ipr (0.05–0.2 mm/rev) at 0.02–0.06" (0.5–1.5 mm) depth of cut. FM2533 is a CVD grade — stable steel applications and nodular cast iron — a balance of wear resistance and chipping resistance.
7 RMC toolholders in stock take this insert — 80° rhombic, 7° clearance, 1/2" inscribed circle, 3/16" thick. Pick by the shank your turret takes.
| 3/4" shank | SCLCL 12-4B · SCLCR 12-4B |
| 1" shank | SCLCL 16-4D · SCLCR 16-4D · SCMCN 16-4D |
| 1-1/4" shank | SCLCL 20-4D · SCLCR 20-4D |
Boring bars and interchangeable heads. 7 more RMC tools take the same insert for internal turning. See RMC boring bars →
Grade & chip breaker selection chart →
Turning insert designations explained · Using a turning formula calculator