Product Overview

For shops utilizing DIN 69871 (SK/DAT) spindle machines, achieving maximum efficiency in heavy roughing requires a tool holder that can handle extreme cutting forces without allowing the end mill to slip. The SK OZ Collet Chuck is the definitive solution. While ER collets (8-degree taper) are great for general work, the OZ collet system (1:10 or approx. 5.7-degree taper) provides a significantly longer surface contact area. This extended taper translates tightening torque into massive, uniform frictional grip along the entire shank of the cutting tool, making it the preferred choice for heavy-depth-of-cut (HDOC) milling and machining tough alloys.

Key Features & Advantages

• Maximum Gripping Force: The shallow 1:10 taper design of the OZ (EOC) collet delivers up to 50% more clamping torque than standard ER systems, absolutely preventing solid carbide end mills from pulling out or spinning under heavy axial loads.

• Heavy-Duty Rigidity: Forged from premium alloy steel (such as 20CrMnTi) and case-hardened to HRC 56-60. The thick-walled construction of the SK taper and chuck body absorbs heavy milling vibrations, preventing chatter and extending the life of your expensive cutting tools.

• Ultra-Precision Runout: The internal collet seat and the external SK machine taper are precision-ground simultaneously. We guarantee a maximum Total Indicator Runout (T.I.R.) of ≤ 0.005mm (5 microns) at the taper, ensuring even chip loads on all cutting flutes.

• Ball-Bearing Clamping Nut: Equipped with a heavy-duty ball-bearing nut that dramatically reduces friction during tightening. This allows operators to easily achieve maximum clamping force without twisting the collet or galling the tool holder face.

• High-Speed Dynamic Balancing: Dynamically balanced to G6.3 @ 15,000 RPM (with optional G2.5 @ 20,000 RPM balancing available) to protect your machine's spindle bearings during high-speed machining (HSM).

Why Partner with Pingyuan Zhenghao Machinery?

• Direct Manufacturer Savings: Bypass trading companies and source heavy-duty DIN 69871 CNC roughing holders directly from our factory for highly competitive wholesale pricing.

• Complete SK Spindle Compatibility: We manufacture the full range of SK tapers for heavy milling: SK40 (the industry standard) and SK50 (for large, high-torque horizontal and vertical mills).

• Standard Heavy-Duty Capacities: Available in the most popular heavy-duty sizes: OZ25 (EOC25) clamping 2-25mm, and OZ32 (EOC32) clamping 3-32mm.

• Coolant-Through Capability (AD/B Form): Designed with internal coolant channels (Form AD) and optional flange coolant delivery (Form B) to direct high-pressure cutting fluid directly to the cutting zone, flushing chips and preventing thermal shock.

Frequently Asked Questions (FAQ) - Selection Guide

Q1: Why should I choose an SK OZ Chuck over an SK ER Chuck?

A: You should choose the SK OZ chuck specifically for heavy roughing and high-feed milling. ER chucks are versatile but can suffer from tool pull-out under heavy loads. The OZ system's longer taper provides the massive grip and rigidity needed to push large end mills through tough materials (like steel, titanium, or Inconel) without the tool slipping.

Q2: Are OZ, EOC, and DIN 6388 collets the same thing?

A: Yes. DIN 6388 is the official standard. OZ (Ortlieb Spannzangen) and EOC (European Standard Collet) are common industry names for this exact same 1:10 taper collet system. They are 100% interchangeable.

Q3: Can I use this holder in a BT40 or CAT40 machine?

A:No. While SK40, BT40, and CAT40 all share the same 7/24 taper angle, the V-flange design (for the automatic tool changer) is completely different. This SK (DIN 69871) holder will only work correctly in a machine spindle designed for SK/DAT tooling.

Q4: How do I tighten the OZ nut?

A: OZ tool holders use a large, round ball-bearing nut with slots cut into the side. You must use a heavy-duty Hook Spanner Wrench (C-Spanner) that matches the outer diameter of the OZ nut (e.g., an OZ25 hook wrench). Unlike ER nuts, you cannot use a standard hex wrench.

Eliminate tool pull-out and maximize your roughing efficiency with our Heavy-Duty DIN 69871 SK OZ Collet Chuck Tool Holders.

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