Sumitomo General Catalog 2025-2026

CBN - SUMIBORON Ballnose Endmills BNBS Type

Hardened Steel 45 to 55HRC

Hardened Steel 55 to 60HRC

Hardened Steel 60 to 65HRC

Pre-hardened Steel

Ballnose

Flutes

Side Milling

Face Milling

R-Grooving

Profiling

● Combination of Special Grade and Spiral Cutting Edge Design: The combination of a special tough SUMIBORON grade with a unique cutting edge design is a breakthrough for high efficiency and smooth endmilling of hardened steels.

L

Fig 1

±0.02

RE

APMX

LF

Body 

Dimensions (mm)

Radius RE

Dia. DC

Cutting Edge Length APMX

Overall Length LF

Shank Dia. DMM

Cat. No.

Stock

Fig

BNBS 2020S BNBS 2030S BNBS 2040S BNBS 2060S BNBS 2080S BNBS 2100S BNBS 2120S

1.0 1.5 2.0 3.0 4.0 5.0 6.0

2.0 3.0 4.0 6.0 8.0

1.5 2.0 3.0 4.5 5.5 6.5 7.5

50 60 70 80 90

4 6 6 6 8

1 1 1 1 1 1 1

      

10.0 12.0

100 110

10 12

Grade: BN350

Recommended Cutting Conditions 1. Use a high-rigidity machine and select a high cutting speed with a low feed rate. 2. Use dry cutting conditions. 3. Make overhang as short as possible. 4. If the work material hardness is lower than 50HRC, try the GSX Ballnose endmill .

Radius Milling

p f

Part Material Cutting Conditions

Hardened Steel (50-57HRC)

Hardened Steel (58-65HRC)

Spindle Speed (min -1 )

Feed Rate (mm/min)

Spindle Speed (min -1 )

Feed Rate (mm/min)

RE ( mm )

26,000 1,100 22,000

1.0 1.5 2.0 3.0 4.0 5.0 6.0

670 450 330 450 330 400 330

700 15,000 530 11,000

18,000 13,000 8,800 6,600 5,300 4,400

610 460 630 530

7,400 5,600 4,500 3,700

0.01DC 0.02DC

0.01DC 0.02DC

a p p f

Standard Depth of Cut

Performance

Part Material : D2 Tool Steel (60HRC Hardness )

Actual Cutting Length : 365 Linear Feet, v B = .005 ank wear” Finished Surface Roughness : Radial Feed Ry1.8μm,

Continued Machining Possible

BN350

Axial Feed Direction Ry2.2μm

825 SFM .00157 IPT .0118” .0118” BNBS2100S

Cutting Speed Feed Rate f Pitch Feed P f Depth of Cut a p Tool

Radial Feed

Feed Direction

Results

× 5,000

× 5,000

L132

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