In our previous discussion, we compared collet chucks with traditional power chucks. Once you decide to adopt a collet system for its high-speed and high-precision benefits, the next strategic step is selecting the specific type of collet and chuck for your machine.
At Auto-Strong (Di Chun Iron Work), with over 40 years of expertise in high-performance workholding, we design our CR and CRA series to be more than just components—they are efficiency boosters for your CNC lathe.
1. Matching the Bar Shape and Size
The versatility of a collet chuck depends on its ability to handle various bar stocks. When selecting a system, ensure it follows international standards for easy collet replacement.
- Standard Profiles: Most bar machining requires Round, Hexagonal, or Square profiles.
- The Auto-Strong Advantage: Our CR and CRA series use DIN6343 specification spring collets. This ensures that users can easily find and swap collets to match their specific bar shapes and sizes, ranging from 26mm up to 80mm capacities.
2. Clamping Mechanism: The "Push Type" Efficiency
Understanding how the chuck operates is key to stability. The Auto-Strong CR and CRA series are Push Type collet chucks.
- How it Works: Instead of pulling the collet back, the sleeve pushes the collet forward into the taper to clamp the workpiece.
- Benefits: This design is specifically optimized for NC/CNC lathes for machining bar stock. When paired with a bar feeder, the material can be fed through the collet chuck hole, significantly improving automated processing efficiency.
3. Spindle Connection: CR vs. CRA
Your machine's spindle nose dictates which series you should choose. Auto-Strong provides two primary mounting options to ensure a perfect fit:
- CR Series (Cylindrical Center Mount): Designed for flat-back or cylindrical mounting. Its installation is identical to a standard through-hole power chuck, making it easy to interchange without complex modifications.
- CRA Series (Short Taper Mount): Specifically designed for spindles with a short taper (e.g., A2-4, A2-5, A2-6, A2-8). This direct-mount design ensures maximum rigidity and high-speed stability, with models like the CRA-26 achieving speeds up to 7,000 RPM.
Quick Selection Reference Table
| Feature | CR Series | CRA Series |
|---|---|---|
| Mounting Type | Cylindrical Center Mount | Short Taper Mount (A2-4 to A2-8) |
| Clamping Design | Push Type | Push Type |
| Collet Standard | DIN6343 | DIN6343 |
| Max Capacity | Up to 80 mm | Up to 80 mm |
| Max Speed | Up to 6,000 RPM | Up to 7,000 RPM |
Conclusion: Choosing between the CR and CRA series comes down to your machine's spindle interface and your speed requirements. Both series offer the "Quick Change" advantage and "High Rigidity" that Auto-Strong is known for worldwide.
Contact Auto-Strong Today
Ready to upgrade your bar machining efficiency? Our technical experts are available to help you select the exact workholding solution for your specific CNC lathe model.