CNMG 120408 Chip Breaker BMR Grade FM2553 / CNMG 432 BMR #FMCarbide

CNMG 120408 / CNMG 432, chip breaker BMR, grade FM2553 — negative 80° rhombic turning insert.

1/2" inscribed circle, 3/16" thick, 1/32" corner radius. The BMR breaker is the roughing geometry: 0.012–0.022 ipr (0.3–0.6 mm/rev) at 0.07–0.22" (1.8–5.5 mm) depth of cut. FM2553 is a CVD (Al₂O₃) grade — tough substrate for heavy interrupted cuts in steel and stainless, heavy roughing in mild steel, and first choice for superalloys.

Specifications

• Insert designation (ISO): CNMG 120408
• Insert designation (inch): CNMG 432
• Insert shape: 80° rhombic (C)
• Clearance angle: 0° — negative (N)
• Tolerance class: M
• Insert type: G — with hole, chipbreaker both sides
• Inscribed circle (I.C.): 1/2" (12.7 mm)
• Thickness: 3/16" (4.76 mm)
• Corner radius: 1/32" (0.79 mm)
• Chip breaker: BMR — Stainless steel — roughing
• Feed rate range: 0.012–0.022 ipr (0.3–0.6 mm/rev)
• Depth of cut range: 0.07–0.22" (1.8–5.5 mm)
• Grade: FM2553
• Coating: CVD (Al₂O₃)
• ISO application range: P20–P35 · M10–M30
• Cutting speed, non-alloy steel: 490–1150 SFM (150–350 m/min)
• Cutting speed, low-alloy steel: 300–980 SFM (90–300 m/min)
• Cutting speed, high-alloy steel: 230–820 SFM (70–250 m/min)
• Cutting speed, ferritic & martensitic stainless: 390–750 SFM (120–230 m/min)
• Cutting speed, austenitic stainless: 260–660 SFM (80–200 m/min)
• Cutting speed, titanium & super-alloys: 110–260 SFM (35–80 m/min)

Tool holders that accept this insert

69 RMC toolholders in stock take this insert — 80° rhombic, 0° — negative clearance, 1/2" inscribed circle, 3/16" thick. Pick by the shank your turret takes.

RMC square-shank toolholders — made in the USA

Boring bars and interchangeable heads. 66 more RMC tools take the same insert for internal turning. See RMC boring bars →

TURNING KNOW-HOW

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01 / SELECTION

Grades & chip breakers

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Explore the chart → 02 / INSERT CODES

Know your insert

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Read the guide → 03 / CUTTING PARAMETERS

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