CNC Back Pull SDC Collet Chucks | Extra Long Slim Tool Holders

Product Overview

Standard ER collet chucks are excellent for general-purpose milling, but their bulky clamping nuts often cause catastrophic interference when machining deep pockets, steep draft angles, or complex mold cavities. The Back Pull SDC Slim Collet Chuck is engineered specifically to solve this problem. By using a shallow-taper DC collet and a specialized flush or ultra-slim nut that pulls the collet backward into the holder, the nose diameter is drastically reduced. This allows you to reach deep into the workpiece with a shorter, more rigid cutting tool, rather than relying on vibration-prone, extra-long end mills.

Key Features & Advantages

• Ultra-Slim Nose Profile: The defining feature. The external diameter at the tip is minimized to provide maximum clearance, making it indispensable for 5-axis contouring and deep mold cavity machining.

• Extra Long Reach: Available in extended gauge lengths (e.g., 100mm, 150mm, 200mm) to reach the bottom of deep parts while keeping the machine spindle safely away from the workpiece.

• Back-Pull Clamping Mechanism: The specialized nut draws the collet directly back into the precision-ground taper. This provides a uniform, 360-degree gripping force that prevents tool pull-out and ensures exceptional rigidity despite the slim design.

• High-Speed & High-Precision: Precision ground to achieve a Total Indicator Runout (T.I.R.) of ≤ 0.005mm at the collet nose. Pre-balanced to G2.5 @ 25,000 RPM, ensuring vibration-free performance and superior surface finishes.

• Premium Alloy Steel: Forged from high-grade 20CrMnTi or equivalent alloy steel, deeply case-hardened, and sub-zero treated to maintain structural integrity and accuracy over thousands of tool changes.

Why Partner with Pingyuan Zhenghao Machinery?

• Direct Manufacturer Savings: Bypass trading companies and source premium high-precision slim chucks directly from our factory for highly competitive wholesale pricing.

• Comprehensive Spindle Compatibility: We manufacture slim chucks for all major CNC spindle platforms:

• MAS 403 BT: BT30, BT40, BT50

• DIN 69871 SK/DAT: SK40, SK50

• DIN 69893 HSK: HSK63A, HSK100A

• Full Range of SDC Sizes: Available for all standard slim collet sizes, including SDC4, SDC6, SDC8, SDC10, and SDC12, allowing you to clamp micro-tools and standard end mills with perfect concentricity.

• Strict Quality Control: Every tool holder is rigorously inspected using 3D CMMs, taper gauges (AT3 standard), and dynamic balancing machines before packaging.

Frequently Asked Questions (FAQ) - Selection Guide

Q1: What is the main advantage of an SDC Slim Chuck over a standard ER Chuck?

A:Clearance. An ER chuck has a large nut that can hit the walls of a deep pocket. An SDC slim chuck has a tiny nose diameter (sometimes only slightly larger than the cutting tool itself), allowing it to fit into tight spaces without interference. It also typically offers better runout accuracy (0.005mm vs. standard ER's 0.008mm-0.015mm).

Q2: What does "Back Pull" mean in this context?

A: In a standard chuck, the nut threads onto the outside of the holder, adding bulk. In a "back pull" design, the nut often threads internally or has a very streamlined external profile that pulls the collet backward into the taper. This design is what allows the nose of the chuck to be so thin.

Q3: Because it is extra long and slim, is it prone to vibration?

A: While any extended tool holder has a higher risk of deflection than a short one, our SDC chucks are made from premium hardened steel and are dynamically balanced. To minimize vibration, you should always choose the shortest possible extended length that still clears your workpiece, and use high-quality, balanced cutting tools.

Q4: Do I need a special wrench to tighten the SDC chuck?

A:Yes. Because the nut is ultra-slim and perfectly cylindrical (to maintain high-speed balance), it does not have standard wrench flats. It requires a specialized roller bearing wrench or a specific slim-profile spanner (often called a "DC wrench" or "Slim Chuck Wrench") to grip the nut securely without damaging it.

Access deep cavities and complex geometries with confidence using our Extra Long SDC Slim Collet Chucks.

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