Kemmler KPS High-Precision Collet Chucks

Available Sizes and Part Numbers

Full range of sizes: see manufacturer catalog.

Purpose and Application

Kemmler KPS precision collet chucks are designed for installation on CNC milling machines and machining centers with SK spindles according to ISO 7388-1 (formerly DIN 69871). The chucks are specifically developed for high-speed machining (HSC / UGV) and executing high-precision finishing and semi-finishing operations. They serve as a direct, highly efficient alternative to hydraulic and shrink fit chucks.

Design and Features

The chuck features a reduced collet taper angle (8° compared to 16° in standard ER collets), providing significantly higher clamping force and greater radial rigidity. The construction is equipped with a smooth drive nut without external slots, minimizing air resistance, noise level, and unbalance during rotation up to 30,000 rpm. Inner taper radial runout does not exceed ≤ 3 µm. Nut clamping is performed using a specialized KPS roller spanner wrench. An RFID chip bore is provided in the body.

Compatibility

The chucks are intended for machine spindles with SK 30 and SK 40 tapers (ISO 7388-1 / DIN 69871). Compatible exclusively with KPS system precision collets: KPS 10 (490EK series) for 1–10 mm diameters and KPS 16 (496EK series) for 4–16 mm diameters. Clamped via specialized KPS nuts (M21.5x1.0 and M32x1.5). Pull studs according to ISO 7388-3 (formerly DIN 69872) are used for spindle retention.

Selection Parameters

Selection is performed based on spindle taper size (SK 30, SK 40) and KPS collet type:

• KPS 10 (490EK): clamping diameters 1–10 mm, nut outer diameter DLN = 27.5 mm;
• KPS 16 (496EK): clamping diameters 4–16 mm, nut outer diameter DLN = 40 mm.

Modifications are available with LPR projections ranging from 60 mm to 160 mm for deep cavity machining.

Key Advantages

• Alternative to Hydraulic and Shrink Fit Chucks: combines the flexibility of collet clamping with enhanced rigidity and extreme accuracy.
• Precision Accuracy: radial runout ≤ 3 µm ensures superior surface finish quality and tool life.
• HSC Optimization: balancing G 2.5 at 30,000 rpm and a smooth nut without slots guarantee minimal vibration at high speeds.
• Slim Contour: reduced nut outer diameters (27.5 mm and 40 mm) minimize contour interference.
• Enhanced Clamping Force: the 8° collet angle delivers reliable shank retention during dynamic milling operations.