Product Overview

While the ER collet system is the industry standard for general-purpose machining due to its wide collapse range, it can struggle with tool pull-out during heavy roughing cuts, especially with large-diameter solid carbide end mills. The OZ Collet Chuck (standardized as DIN 6388 or EOC) is engineered specifically to solve this problem. The OZ system uses a 1:10 (approx. 5.7-degree) taper angle, which is much shallower and significantly longer than the 8-degree ER taper. This extended surface contact area generates massive frictional gripping force along the entire length of the tool shank, providing extreme rigidity and completely eliminating the risk of the end mill slipping or pulling out under heavy axial loads.

Key Features & Advantages

• Extreme Gripping Force: The long 1:10 taper design of the OZ collet provides up to 50% more clamping torque than an equivalent-sized ER collet, making it perfect for heavy-duty milling, slotting, and hard metal machining.

• Superior Rigidity: Forged from premium alloy steel (such as 20CrMnTi) and case-hardened to HRC 56-60. The robust, thick-walled construction of the chuck body absorbs heavy milling vibrations, preventing chatter and extending tool life.

• High 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 even chip loads on all cutting flutes.

• Ball-Bearing Nut Design: Equipped with a heavy-duty, friction-reducing ball-bearing clamping nut. This allows operators to easily achieve maximum tightening torque without twisting the collet or scoring 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 spindle and ensure smooth operation during high-speed machining (HSM).

Why Partner with Pingyuan Zhenghao Machinery?

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

• Comprehensive Spindle Compatibility: We manufacture OZ chucks for all major machine tapers: BT30, BT40, BT50, SK40, SK50, CAT40, CAT50, NT, and MT.

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

• Coolant-Through Capability: Designed with internal coolant channels (Form AD) to deliver high-pressure cutting fluid directly to the cutting zone, flushing chips and preventing thermal shock to the tool.

Frequently Asked Questions (FAQ) - Selection Guide

Q1: What is the difference between OZ, EOC, and DIN 6388?

A: They are exactly the same thing. DIN 6388 is the official German standard for this collet system. OZ (Ortlieb Spannzangen) is the original manufacturer's designation that became the common industry name. EOC (European Standard Collet) is another widely used term for the same 1:10 taper collet system.

Q2: Should I use an OZ chuck or an ER chuck for milling?

A:

• Use an ER Chuck: For general-purpose milling, drilling, tapping, and finishing operations. ER collets have a wider collapse range (usually 1mm), meaning you need fewer collets to cover all tool sizes.

• Use an OZ Chuck: For heavy roughing, high-feed milling, or machining tough materials (like titanium or Inconel) with end mills larger than 12mm (1/2"). OZ collets have a smaller collapse range (usually 0.5mm) but provide vastly superior grip and rigidity to prevent tool pull-out.

Q3: Can I use ER collets in an OZ tool holder?

A:No. The taper angles and physical dimensions are completely different. An OZ tool holder requires specific OZ (DIN 6388 / EOC) collets.

Q4: Do I need a special wrench to tighten it?

A: Yes, 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) to achieve the massive clamping force required.

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

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