SNMG-BR – INNOT insert

SNMG-BR

90° negative square insert for roughing stainless steels, with BR chipbreaker and INNOT PVD grades.

ISO M
Roughing
PVD
★ IT7225

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Technical data sheet PDFCutting data, sizes and grades

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Fits on
45° and 75° toolholders for roughing

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INNOT grades

CVD, PVD and cermet for ISO P, M, K, S

Standard ISO designation

Compatible with the insert holders you use

Technical support

We help you choose grade and chipbreaker

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Description

ISO specifications

ISO RADIUS (RE) AVAILABLE GRADES CHIPBREAKER
SNMG1204 0.8 – 1.2 IT7125 – IT7225 BR
SNMG1506 1.2 IT7125 – IT7225 BR
SNMG1906 1.6 IT7125 – IT7225 BR

BR chipbreaker data sheet

Operation Roughing
ISO material M (stainless steels)
Tolerance M
Features Chipbreaker for roughing stainless steel. The optimised high-strength profile makes it suitable for interrupted cuts and light-load roughing; depths of cut and feeds in the cutting data table. 90° square shape: the strongest of the negative inserts, with 8 usable cutting edges (4 per side); ideal for roughing, facing and 45° chamfers.

Available INNOT grades

Grade ISO Coating Composition Application
IT7125 M PVD AlTiN Universal grade for turning stainless steel in continuous and interrupted cuts. Smooth, low-friction coating, high nano-hardness and excellent oxidation resistance.
IT7225 ★ M PVD AlTiSiN + TiSiN First-choice grade for turning stainless steel. Nano-gradient coating on a sub-micron grain substrate: excellent wear resistance and toughness.

★ Recommended grade for this chipbreaker. PVD = physical vapour deposition coating. ISO M = stainless steels.

Recommended cutting data

Printable cutting data tableAll the data on this page in an INNOT PDF to keep in the shop.Download PDF
External turning of stainless steel (ISO M) – BR chipbreaker

Recommended cutting data by material and cutting condition (stable, average, difficult).

Material Condition Vc (m/min) by grade fn (mm/rev) ap (mm)
Austenitic stainless steel ≤ 200 HB
(AISI 304, 316…)		 Stable IT7125: 80 – 150
IT7225: 80 – 150		 0.18 – 0.66 1.70 – 7.00
Austenitic stainless steel ≤ 200 HB
(AISI 304, 316…)		 Average IT7125: 80 – 150
IT7225: 80 – 150		 0.18 – 0.61 1.70 – 7.00
Austenitic stainless steel ≤ 200 HB
(AISI 304, 316…)		 Difficult IT7125: 80 – 150
IT7225: 80 – 150		 0.18 – 0.56 1.70 – 7.00
Martensitic stainless steel > 200 HB
(AISI 431, 420…)		 Stable IT7225: 70 – 140 0.18 – 0.66 1.70 – 7.00
Martensitic stainless steel > 200 HB
(AISI 431, 420…)		 Average IT7225: 70 – 140 0.18 – 0.61 1.70 – 7.00
Martensitic stainless steel > 200 HB
(AISI 431, 420…)		 Difficult IT7225: 70 – 140 0.18 – 0.56 1.70 – 7.00

Guide values for the BR chipbreaker. On martensitic stainless steel only IT7225 is recommended.

Internal turning (boring) of stainless steel (ISO M) – BR chipbreaker

Starting values for internal turning with a boring bar, derived from this insert's external turning data: cutting speed −15%, feed −20%, maximum depth of cut −40%. Negative inserts are mounted on boring bars for bores from about Ø 25 mm upwards (Ø 32–40 mm for the larger sizes).

Material Condition Vc (m/min) by grade fn (mm/rev) ap (mm)
Austenitic stainless steel ≤ 200 HB
(AISI 304, 316…)		 Stable IT7125: 70 – 130
IT7225: 70 – 130		 0.14 – 0.53 1.70 – 4.20
Austenitic stainless steel ≤ 200 HB
(AISI 304, 316…)		 Average IT7125: 70 – 130
IT7225: 70 – 130		 0.14 – 0.49 1.70 – 4.20
Austenitic stainless steel ≤ 200 HB
(AISI 304, 316…)		 Difficult IT7125: 70 – 130
IT7225: 70 – 130		 0.14 – 0.45 1.70 – 4.20
Martensitic stainless steel > 200 HB
(AISI 431, 420…)		 Stable IT7225: 60 – 120 0.14 – 0.53 1.70 – 4.20
Martensitic stainless steel > 200 HB
(AISI 431, 420…)		 Average IT7225: 60 – 120 0.14 – 0.49 1.70 – 4.20
Martensitic stainless steel > 200 HB
(AISI 431, 420…)		 Difficult IT7225: 60 – 120 0.14 – 0.45 1.70 – 4.20

With a boring bar overhang above 3 times the diameter (steel bar) or 5 times (carbide or anti-vibration bar), reduce speed and feed further. Use the bar's internal coolant to clear the chips.

Grade selection by cutting condition
Cutting condition Recommended grade
Stable (continuous cut) IT7225
Average IT7225 / IT7125
Difficult (interrupted cut) IT7125

IT7225 allows higher cutting speeds; IT7125 offers greater toughness in interrupted cuts.