SNMG 120408 Chip Breaker BC Grade FM2553 / SNMG 432 BC #FMCarbide

SNMG 120408 / SNMG 432, chip breaker BC, grade FM2553 — negative square turning insert.

1/2" inscribed circle, 3/16" thick, 1/32" corner radius. The BC breaker is the medium roughing & cast iron geometry: 0.008–0.020 ipr (0.2–0.5 mm/rev) at 0.06–0.16" (1.5–4 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): SNMG 120408
• Insert designation (inch): SNMG 432
• Insert shape: square (S)
• 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: BC — Steel — medium roughing & cast iron
• Feed rate range: 0.008–0.020 ipr (0.2–0.5 mm/rev)
• Depth of cut range: 0.06–0.16" (1.5–4 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

42 RMC toolholders in stock take this insert — square, 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. 16 more RMC tools take the same insert for internal turning. See RMC boring bars →

TURNING KNOW-HOW

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Practical guides to choosing, understanding and using your inserts.

01 / SELECTION

Grades & chip breakers

Explore the grade and chip-breaker selection chart for your turning operation.

Explore the chart → 02 / INSERT CODES

Know your insert

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Read the guide → 03 / CUTTING PARAMETERS

Turning calculations

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