Kemmler SK Weldon End Mill Holders DIN 6359

Available Sizes and Part Numbers

Purpose and Application

Weldon Kemmler toolholders complying with DIN 6359 are engineered for CNC milling machines and machining centers equipped with SK spindles according to ISO 7388-1 (DIN 69871). They are designed for rigid clamping of solid carbide and indexable end mills, drills, and other cutting tools featuring a cylindrical shank with a side clamping flat according to DIN 1835 Form B (Weldon). This tooling is optimized for roughing, semi-finishing, and heavy-duty milling of steels, cast irons, and non-ferrous metals.

Design and Features

Tool clamping is executed via a locking screw that tightens perpendicularly against the flat surface of the Weldon shank, preventing tool slippage or pull-out under heavy axial and radial forces during heavy machining. Starting from clamping diameters of 25 mm (Ø 25, 32, 40 mm), holders feature double clamping screws for maximum holding security. The bore is manufactured with extreme precision to H4 tolerance. Radial runout does not exceed ≤ 3 µm, and factory balancing complies with G 2.5 at 25,000 rpm. A pre-drilled slot for an RFID chip is integrated into the body as standard.

Compatibility

Compatible with machine spindles featuring SK 30, SK 40, and SK 50 tapers (ISO 7388-1 / DIN 69871). Designed for tools with DIN 1835-B shanks in corresponding diameters (6 to 40 mm). Pull studs compliant with ISO 7388-3 (formerly DIN 69872) are used for spindle mounting.

Selection Parameters

Toolholder selection depends on the spindle taper (SK 30, SK 40, SK 50) and the tool shank diameter DCONWS (6, 8, 10, 12, 14, 16, 18, 20, 25, 32, 40 mm). Based on gage length LPR, options include short standard versions (35–63 mm), base versions (50–100 mm), and extended modifications (130, 160, 200 mm) for deep cavity milling. Coolant supply options are available in Form AD (for SK 30) and Form AD/B (universal through-center or flange coolant supply for SK 40 and SK 50).

Key Advantages:

• Absolute Pull-Out Protection: The clamping screw securely locks the Weldon shank flat, eliminating tool movement during heavy-duty milling.
• High Precision Fit: H4 bore tolerance and radial runout ≤ 3 µm ensure balanced load distribution across cutting edges.
• Dual Clamping for Large Diameters: Two clamping screws for diameters starting at 25 mm guarantee maximum torque transmission.
• Precision Balancing: Fine-balanced to G 2.5 at 25,000 rpm to minimize vibration loads on the spindle.
• Wide Range of Lengths: Extended executions up to 200 mm gage length enable deep machining in hard-to-reach areas.