WNMG-BM – INNOT insert

WNMG-BM

80° negative trigon insert for semi-finishing stainless steels, with BM chipbreaker and INNOT PVD grades.

ISO M
Semi-finishing
PVD
★ IT7225

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Technical data sheet PDFCutting data, sizes and grades

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Fits on
95° external turning toolholders

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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

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Description

ISO specifications

ISO RADIUS (RE) AVAILABLE GRADES CHIPBREAKER
WNMG06T3 1.2 IT7125 – IT7225 BM
WNMG0604 1.2 IT7125 – IT7225 BM
WNMG0804 0.4 – 0.8 – 1.2 IT7125 – IT7225 BM

BM chipbreaker data sheet

Operation Semi-finishing
ISO material M (stainless steels)
Tolerance M
Features Chipbreaker for semi-finishing stainless steel. Micro-preparation of the cutting edge provides both sharpness and high strength, to machine stainless steel with high productivity and long insert life. 80° trigon shape: 6 usable cutting edges (3 per side) with an 80° tip, for longitudinal turning and facing with 95° toolholders.

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) – BM 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: 90 – 170
IT7225: 90 – 170		 0.10 – 0.52 1.00 – 5.80
Austenitic stainless steel ≤ 200 HB
(AISI 304, 316…)		 Average IT7125: 90 – 170
IT7225: 90 – 170		 0.10 – 0.47 1.00 – 5.80
Austenitic stainless steel ≤ 200 HB
(AISI 304, 316…)		 Difficult IT7125: 90 – 170
IT7225: 90 – 170		 0.10 – 0.42 1.00 – 5.80
Martensitic stainless steel > 200 HB
(AISI 431, 420…)		 Stable IT7225: 80 – 160 0.10 – 0.52 1.00 – 5.80
Martensitic stainless steel > 200 HB
(AISI 431, 420…)		 Average IT7225: 80 – 160 0.10 – 0.47 1.00 – 5.80
Martensitic stainless steel > 200 HB
(AISI 431, 420…)		 Difficult IT7225: 80 – 160 0.10 – 0.42 1.00 – 5.80

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

Internal turning (boring) of stainless steel (ISO M) – BM 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: 75 – 145
IT7225: 75 – 145		 0.08 – 0.42 1.00 – 3.50
Austenitic stainless steel ≤ 200 HB
(AISI 304, 316…)		 Average IT7125: 75 – 145
IT7225: 75 – 145		 0.08 – 0.38 1.00 – 3.50
Austenitic stainless steel ≤ 200 HB
(AISI 304, 316…)		 Difficult IT7125: 75 – 145
IT7225: 75 – 145		 0.08 – 0.34 1.00 – 3.50
Martensitic stainless steel > 200 HB
(AISI 431, 420…)		 Stable IT7225: 70 – 135 0.08 – 0.42 1.00 – 3.50
Martensitic stainless steel > 200 HB
(AISI 431, 420…)		 Average IT7225: 70 – 135 0.08 – 0.38 1.00 – 3.50
Martensitic stainless steel > 200 HB
(AISI 431, 420…)		 Difficult IT7225: 70 – 135 0.08 – 0.34 1.00 – 3.50

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.

Depth of cut and insert size. The table shows the chipbreaker range (ap up to 5.8 mm), valid for all negative shapes. The trigon has a short cutting edge: with WNMG08 (8.7 mm cutting edge) keep the depth of cut within about half the edge, i.e. about 4 mm, and about 3 mm with WNMG06 (6.6 mm cutting edge). For deeper cuts choose an 80° CNMG, which has the same tip angle and a longer cutting edge.