What This 25 Type Collet Does Differently This is a CNC Machined Auto Lathe 25 Type Multi Slot Round Bore Collet. It grips round stock from 3mm to 25mm diameter on sliding headstock lathes and automat
This is a CNC Machined Auto Lathe 25 Type Multi Slot Round Bore Collet. It grips round stock from 3mm to 25mm diameter on sliding headstock lathes and automatic screw machines. The multi-slot design distributes clamping force evenly across the bore, holding parts with a total indicated runout (TIR) of ≤0.005mm. That means your turned parts come off the machine with consistent wall thickness, without ovality or chatter marks. We machine every collet from hardened alloy steel, reach 58-60 HRC, and ship from our Dongguan factory in 7-10 days. This is precision manufacturing made in China, with no MOQ.
A solid bore collet only contacts the workpiece at three or four points, leaving gaps that let thin wall parts flex. Our 25 type collet uses eight precision-cut slots. These slots close radially with even pressure, wrapping the entire circumference of the bar. The result is a grip that holds 2mm rod without crushing it, yet still clamps a 25mm shaft tight enough for heavy roughing cuts. Each slot is wire-cut, not milled, to avoid stress risers and micro-cracks. Slot width is 0.8mm, and the depth is calculated to maintain spring-back force after 50,000 cycles.
We start with 20CrMnTi case-hardening steel. This grade gives a tough core for impact resistance and a hard case for wear resistance. After CNC machining the 25 type body and cutting the slots, we gas-carburize the collet at 920°C for 6 hours. The case depth reaches 0.8-1.2mm, and surface hardness lands at 58-60 HRC. Core hardness stays at 35-40 HRC, so the collet flexes without cracking. We finish with a black oxide coating that resists rust from coolant. This heat treatment sequence is the same one we use for high-volume automotive collets that run 24/7.
Every collet is 100% inspected, not sample-checked. We check the bore diameter with an air gauge that resolves to 0.001mm. We mount the collet in a test holder and measure runout at the nose with a dial indicator—only collets under 0.005mm TIR pass. We also test grip force on a hydraulic pull tester: a 25mm collet must hold 12 kN of axial force before slipping. The surface finish inside the bore is verified with a profilometer, Ra 0.4µm or better. Each collet gets a serial number and a test report PDF that we email with your invoice.
This collet has a 25mm body diameter, matching standard 25 type auto lathe spindles. The bore range covers 3mm to 25mm in 1mm increments, and we can make custom bore sizes to 0.01mm accuracy. The overall length is 78mm, with a 30° taper at the nose. The thread on the back is M22x1.5 standard. We keep the bore tolerance at H7 for the unclamped state, which means a 10mm collet measures 10.000mm to 10.021mm when open. Clamping force range is adjustable from 5 to 12 kN depending on drawbar pull.
| Specification | Value / Range |
|---|---|
| Body Type | 25 Type (25mm body diameter) |
| Bore Range | 3mm – 25mm (custom bores available) |
| Bore Tolerance (open) | H7 (e.g., 10.000–10.021mm) |
| Total Runout (TIR) | ≤0.005mm |
| Surface Finish (bore) | Ra 0.4µm |
| Hardness | 58–60 HRC case, 35–40 HRC core |
| Case Depth | 0.8–1.2mm |
| Slot Count | 8 slots |
| Slot Width | 0.8mm |
| Grip Force (25mm bore) | 12 kN axial |
| Lead Time | 7–10 working days |
| MOQ | No MOQ (1 piece accepted) |
Before ordering, measure three things: your spindle nose taper angle (must be 30°), your drawbar thread (M22x1.5 standard, but we can match others), and your bar stock diameter. If your stock is 12.7mm, order a 12.7mm bore, not a 13mm bore. The collet has 0.2mm of closing range, so it grips from 12.5mm to 12.7mm. For hex or square stock, we can cut a matching bore shape—but this product page is for round bore collets. If you are unsure about your spindle spec, send us a photo of the current collet and the machine model. We will confirm compatibility within one working day.
We are the factory. BQUQ is a 20-year CNC machining shop in Dongguan, China, with 40 CNC lathes and 15 machining centers. When you buy from us, you skip the trading company markup. You also get direct access to our engineers—not a sales rep reading a script. We can modify slot depth, bore tolerance, or coating for your specific application without charging a redesign fee. This is why our customers in Germany, Japan, and the US reorder every quarter. Our precision manufacturing process is transparent: we will video-call you during the inspection of your lot if you request it.
Clean the spindle taper with a lint-free cloth—dirt here causes 0.01mm runout. Apply a thin film of light oil to the collet's outer taper, not the bore. Insert the collet and pull it in with the drawbar, then measure runout at the nose with a test bar. If you see more than 0.005mm, re-seat the collet once. If it still reads high, check your spindle nose for wear. For best results, use a torque wrench on the drawbar to the same setting every time. This collet is designed for 5,000 to 8,000 rpm, but balanced versions are available for 12,000 rpm if you request the 'H' suffix.
No MOQ—we accept a single piece order for this 25 type collet, and you still get the full inspection report.
Yes, we can machine any bore diameter from 3mm to 25mm to H7 tolerance, and adjust slot depth for thin-wall or soft materials within 2 days.
Every collet, regardless of order size, goes through the same air-gauge bore check, runout test, and grip force test, and we email the test report.
Standard lead time is 7-10 working days, but we can expedite a single collet to 48 hours for a 30% surcharge.
Send us your drawing or just the bore size and machine model. We will reply with a firm price, lead time, and our recommended collet setup. For help with tooling, read our CNC cutting tool selection guide to match the collet with the right end mills. To understand the limits of our tolerances, check the CNC machining tolerances guide before you specify an impossible bore tolerance. Email your drawing to sc@bquq.com or WhatsApp us at +86 13713157787. We answer within 12 hours, even on weekends.
| 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 |
