BB Unequal Helix Carbide End Mill – JIN, BK40-SUS, BK40-UM

BB Unequal Helix Carbide End Mill Series

Engineered for high-performance dynamic milling, trochoidal machining, and side milling. All three series feature an unequal helix angle design that actively dampens vibration, improves surface finish, and extends tool life.

🔶 JIN Series (BB-JIN)

Geometry: 38° + 40° unequal helix angle (8° differential), asymmetric design
Coating: TiZr (Titanium Zirconium) — excellent heat resistance and lubricity
Substrate: High hardness and high toughness carbide
Applications: Stainless steel, titanium alloy, heat-resisting alloy, superalloy, mild steel, brass, copper, non-ferrous metals
Material grades: A3, 45#, 40Cr, 20Cr, 304, 316L, TC4, TC6, 4J29
Machining strategies: Side milling, dynamic milling, trochoidal machining, layer milling

Main workpiece materials: duplex stainless steel, precipitation-hardening stainless steel, austenitic stainless steel, martensitic stainless steel, ferritic stainless steel, and titanium alloy.
Water-soluble cutting fluid is recommended for machining heat-resistant alloys to achieve better performance.
Compared with conventional end mills, the vibration-damped end mill provides an excellent effect in suppressing high-frequency chatter. However, if the rigidity of the machine tool or workpiece clamping is insufficient, reduce the spindle speed and feed rate proportionally according to the table above, or decrease the depth of cut before use.
If the depth of cut is small, the spindle speed and feed rate may be further increased.

🔷 BK40-SUS Series

Geometry: 38° primary helix + 41° secondary helix — optimized for vibration damping
Rake angle: High positive radial rake for free-cutting action
Clearance angle: Optimized for maximum tool life
Substrate: High hardness and high toughness carbide
Applications: Stainless steel, titanium alloy, heat-resisting alloy, superalloy, mild steel, brass, copper, non-ferrous metals
Material grades: A3, 45#, 304, 316L, TC4, TC6
Machining strategies: Side milling, dynamic milling, trochoidal machining

Machining parameters shall be adjusted appropriately according to tool holder clamping conditions, fixtures, and machine tool rigidity.
Water-soluble cutting fluid is recommended for machining stainless steel and titanium alloys.
Main materials of Carbon Steel / Alloy Steel: (A3, 45# steel, 20Cr, 40Cr, 20CrMo, 35CrMo, 42CrMo, 20CrMnTi, 35CrMoA, etc.)
Main materials of Stainless Steel / Titanium Alloy: (201, 202, 301, 304, 316, 430, 630, TC4, TC6, etc.)

⬛ BK40-UM Series (Ultra-Hard Materials)

Geometry: Unequal helix angle — vibration suppression for hard material cutting
Applications: Oxygen-cut parts, welded components, die steel, tool steel, heat-treated high-hardness stainless steel
Material grades: SKD11, 718H, P20, Cr12, 430, 630
Hardness range: HRC 45–60

Machining strategies: Side milling, dynamic milling, trochoidal machining, layer milling

📋 Usage Recommendations

Before use, measure tool runout. If runout exceeds 0.01 mm, correct before cutting.
Minimize tool overhang from the chuck. Longer overhang requires reduced speed, feed, and depth of cut.
If abnormal vibration or noise occurs, reduce spindle speed and cutting parameters until stable.
Use spray or mist coolant for steel cutting to maximize tool life.
Not suitable for low-speed machines such as bench drills or hand drills.