What This Chuck Is and Why It Cuts Your Setup Time This is a CNC Machined Auto Lathe 25 Type Round Bore Spring Collet Chuck engineered for high-speed bar feeding and secondary machining operations. Y
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What This Chuck Is and Why It Cuts Your Setup Time This is a CNC Machined Auto Lathe 25 Type Round Bore Spring Collet Chuck engineered for high-speed bar feeding and secondary machining operations. Y
This is a CNC Machined Auto Lathe 25 Type Round Bore Spring Collet Chuck engineered for high-speed bar feeding and secondary machining operations. You get guaranteed 0.005 mm total indicated runout (TIR) and a hardness of HRC 58-60, which means your tool or workpiece stays concentric through thousands of cycles. Standard lead time is 5 working days from drawing approval, and we ship globally from our Dongguan factory.
The 25 type refers to the front taper angle and body geometry that seats into your auto lathe spindle. The round bore is ground after heat treatment, not before, so the internal diameter holds true to within +0.005 / -0.000 mm. This eliminates the "bell mouth" effect you get from cheaper ground-then-hardened chucks. The spring collet action distributes clamping force evenly across 360 degrees, which keeps thin-wall parts from deforming and stops tool chatter at spindle speeds up to 8,000 RPM.
We start with 20CrMnTi alloy steel for the body and 65Mn spring steel for the collet segments. The body is carburized to a case depth of 0.8 - 1.2 mm, then hardened to HRC 58-60. The spring slots are wire-cut after hardening to avoid stress risers. We then cryogenically treat every unit at -120°C for 4 hours to convert retained austenite, which is why our chucks hold their grip force within 5% after 1 million open-close cycles. Surface finish on the bore and taper is Ra 0.4 µm, and the outer body is black oxide coated for corrosion resistance.
| Parameter | Value / Range |
|---|---|
| Model | 25 Type Round Bore Spring Collet Chuck |
| Body Material | 20CrMnTi alloy steel (carburized) |
| Collet Material | 65Mn spring steel |
| Hardness (Body) | HRC 58-60 |
| Hardness (Collet segments) | HRC 45-50 (spring tempered) |
| Round Bore Diameter Range | Ø3.0 mm – Ø25.0 mm (custom bore available) |
| Total Indicated Runout (TIR) | ≤ 0.005 mm |
| Surface Finish (bore & taper) | Ra 0.4 µm |
| Clamping Force Repeatability | ± 2% |
| Max Recommended Spindle Speed | 8,000 RPM |
| Lead Time (standard size) | 5 working days |
| MOQ | No MOQ - 1 piece accepted |
We don't batch test. Every single chuck goes through a 3-step quality gate. First, a coordinate measuring machine (CMM) checks the taper angle and bore concentricity. Second, we mount the chuck on a live test spindle and measure TIR with a laser interferometer—you get the actual runout reading printed in the QC report. Third, we cycle the collet 500 times under air pressure to verify spring return force and slot integrity. If any unit fails, it is scrapped, not reworked. That is why we can offer a 0.3% field failure rate guarantee.
This chuck uses the standard 25 type pull-back taper, so it drops onto most Japanese and Korean auto lathes (Citizen, Star, Tsugami, Hanwha) with zero adapter plates. The round bore accepts round stock from Ø3 mm to Ø25 mm. If your spindle uses a different draw tube thread, we can machine the rear thread (M16, M18, M20, or 5/8"-18) at no extra charge. Just send us your draw tube drawing, and we will match the thread pitch exactly.
Cast chucks have porosity that causes micro-cracks under cyclic load. Milled chucks leave tool marks that trap coolant and cause corrosion. Our chuck is fully CNC machined from solid bar stock, then wire-cut, then ground. This is precision manufacturing, made in China, but with the same process control you expect from a Swiss shop. The result is a collet chuck that holds its rated TIR for at least 300,000 cycles without re-grinding. And because we are the factory, not a trading company, you get that quality at a direct cost—typically 20-30% below US or European equivalents.
Yes, no MOQ—you can order a single CNC Machined Auto Lathe 25 Type Round Bore Spring Collet Chuck for prototyping or a line trial, and we will treat it with the same inspection rigor as a 1,000-piece order.
Yes, we can grind any round bore between Ø3 mm and Ø25 mm, and we can cut any rear thread (metric or inch) to match your draw tube within 24 hours of receiving your drawing.
Each shipment includes a material certificate, a hardness test report, a CMM dimensional report, and a live-run TIR measurement sheet with your chuck's serial number.
Standard sizes ship in 5 working days; custom bore or thread adds 2-3 days, so maximum 8 working days from drawing approval to dispatch from Dongguan.
Stop guessing if your current collet chuck is the weak link in your cycle time. Send us your spindle drawing or just your bar diameter and thread size. We will reply within 12 hours with a firm unit price, a lead time commitment, and a DFM (Design for Manufacturing) note if we see a way to improve your clamping setup. For reference on tool selection and tolerance stacking, read our CNC cutting tool selection guide and our CNC machining tolerances guide.
Email: sc@bquq.com
WhatsApp: +86 13713157787
Send your drawing now—we will confirm the bore, thread, and hardness within 12 hours.
| Parameter | Capability |
|---|---|
| Materials | AL6061/7075, SUS303/304/316, 45# steel, T2 copper, H59 brass, POM, PEEK, nylon |
| Tolerance | ±0.005mm standard, ±0.003mm on request |
| Machines | 3/4/5-axis CNC, turn-mill, Swiss lathe |
| Surface | Anodizing, nickel, zinc, passivation, sandblast, polish |
| Size Range | Max 400 x 300 x 200 mm |
| Prototype | 72 hours, no MOQ on samples |
| Inspection | Full report per batch, CMM data on request |
