Kemmler 3° Slim Shrink Fit Chucks

Available Sizes and Part Numbers

Purpose and Application

Kemmler 3° Slim series shrink fit chucks are designed for use on high-speed CNC milling machines and machining centers with SK 40 spindles according to ISO 7388-1 (DIN 69871). The extended, narrow design with an internal 3° taper angle is developed specifically for mold and die making as well as complex structural parts, where standard 4.5° shrink chucks create interference when machining deep cavities and side walls.

Design and Features

The chuck is manufactured from heat-resistant case-hardened steel. By reducing the outer taper angle to 3°, the nose diameter BTED is only 9 mm (for Ø 3 mm) and 18 mm (for Ø 12 mm). Thermal expansion and subsequent cooling provide uniform, solid clamping of the tool shank without mechanical components. Inner taper radial runout is ≤ 3 µm. Dynamic balancing meets class G 2.5 at 25,000 rpm. An adjustment screw and an RFID chip bore are provided in the body.

Compatibility

The chucks are designed for machine spindles with SK 40 tapers (ISO 7388-1 / DIN 69871). Clamps solid carbide (HM) shanks with h4 tolerance (diameters 3, 4, 5 mm) and carbide/HSS shanks with h6 tolerance (diameters 6, 8, 10, 12 mm). Spindle retention is achieved via ISO 7388-3 pull studs (formerly DIN 69872). Heating is performed using induction, contact, or hot-air shrink fit units.

Selection Parameters

Selection is based on tool shank diameter (3, 4, 5, 6, 8, 10, 12 mm) and projection length LPR:

• LPR = 80 mm: standard compact chucks;
• LPR = 120 mm: extended chucks for medium depth;
• LPR = 160 mm: extended chucks for extra-deep cavity machining.

Key Advantages

• Ultra-Slim 3° Contour: provides clearance in deep mold cavities without colliding with workpiece walls.
• Precision Accuracy: radial runout ≤ 3 µm significantly improves cutting edge life and surface finish quality.
• High-Speed Balancing: class G 2.5 at 25,000 rpm guarantees vibration-free operation at high spindle speeds.
• Reliable Thermal Clamping: absence of moving mechanical parts delivers high clamping force and symmetrical grip.
• Heating Versatility: suitable for induction, contact, and hot-air shrink fit units.