Product Overview

The DIN 69871 SK ER Collet Chuck is one of the most widely used and versatile tool holding systems in the global CNC machining industry, particularly dominant in European-built machining centers. The ER collet system allows a single tool holder to clamp a wide range of cylindrical shank tools—including end mills, drills, reamers, and taps—simply by changing the collet. Our SK tool holders feature a V-flange design optimized for automatic tool changers (ATC) and are precision-manufactured to ensure the taper seats perfectly into the machine spindle, providing maximum gripping force and vibration dampening during heavy cutting.

Key Features & Advantages

• Premium Material & Hardness: Constructed from high-quality case-hardened alloy steel (such as 20CrMnTi). The core remains tough to absorb milling vibrations, while the surface is hardened to HRC 56-60 for superior wear resistance and longevity.

• Ultra-Precision Runout: The internal collet seat and the external machine taper are simultaneously ground to exacting tolerances. We guarantee a maximum Total Indicator Runout (T.I.R.) of ≤ 0.005mm (5 microns) at the taper, ensuring extended tool life and superior surface finishes.

• High-Speed Dynamic Balancing: To protect your machine's spindle bearings and ensure flawless performance at modern cutting speeds, our SK holders are dynamically balanced by default to G6.3 @ 15,000 RPM, with optional high-precision balancing up to G2.5 @ 25,000 RPM.

• Coolant-Through Capability (AD/B Form): Designed with internal coolant channels (Form AD) through the center, and optional flange coolant delivery (Form B), allowing high-pressure cutting fluid to reach the cutting edge directly for improved chip evacuation and thermal control.

• Comprehensive ER Range: Available to fit all standard ER collet sizes, including ER11, ER16, ER20, ER25, ER32, ER40, and ER50, providing clamping capacities from 1mm up to 34mm.

Why Partner with Pingyuan Zhenghao Machinery?

• Direct Manufacturer Savings: Bypass trading companies and source premium DIN 69871 CNC tooling directly from our factory for highly competitive wholesale pricing.

• Complete Spindle Compatibility: We manufacture the full range of SK tapers: SK30 (for compact, high-speed machines), SK40 (the industry standard), and SK50 (for heavy-duty, high-torque milling).

• Nut Variations: Choose from standard Hex nuts (UM type), Mini nuts (M type) for tight clearances, or high-speed bearing nuts for reduced friction and increased clamping force.

• Strict Quality Control: Every tool holder undergoes rigorous inspection using 3D CMMs and taper gauges to verify dimensional accuracy, taper angle (AT3 standard), and concentricity before packaging.

Frequently Asked Questions (FAQ) - Selection Guide

Q1: What is the difference between SK, DAT, and JT tool holders?

A: They are generally the exact same thing. DIN 69871 is the official German standard. SK (Steilkegel, meaning "steep taper" in German) is the most common abbreviation. DAT and JT are alternative designations used by different machine tool builders or in different regions. They all feature the same 7/24 taper and V-flange design for the ATC.

Q2: How is an SK40 holder different from a BT40 or CAT40 holder?

A: While SK40, BT40, and CAT40 all share the same 7/24 taper angle and fit into a "40-taper" spindle, they are NOT interchangeable in the Automatic Tool Changer (ATC).

• SK40 (DIN 69871): Has a specific V-flange thickness and an asymmetrical drive key slot design.

• BT40 (MAS 403): Has a thicker, symmetrical V-flange located closer to the taper.

• CAT40 (ANSI B5.50): Has an asymmetrical V-flange design (similar to SK) but uses Imperial (inch) pull stud threads.

• Crucial: You must use the exact style of tool holder specified by your CNC machine manufacturer.

Q3: What does "Form AD/B" mean for coolant delivery?

A: This refers to how the cutting fluid travels through the tool holder:

• Form AD: Coolant flows straight through the center of the pull stud and out through the tool.

• Form B: Coolant is injected through two holes located on the V-flange of the tool holder.

• Form AD/B: The holder is manufactured to support both methods. It comes with the flange holes plugged (acting as Form AD). If your machine uses flange coolant, you simply remove the set screws to convert it to Form B.

Q4: Should I choose a standard nut or a mini nut?

A: A standard (Hex or UM) nut provides the maximum clamping force and is best for general milling. A Mini (M) nut has a much smaller outside diameter, making it ideal for machining deep pockets, working near tall fixtures, or 5-axis applications where tool clearance is critical.

Maximize your machining precision and tool life with our DIN 69871 SK ER Collet Chuck Tool Holders.

Contact our sales team today for a complete catalog and bulk pricing.