This is a complete auto lathe collet kit: the collet body, the spanner wrench set, and the drawbar nut. It is built for CNC sliding-head lathes and Swiss-type machines that need sub-micron grip repeat
This is a complete auto lathe collet kit: the collet body, the spanner wrench set, and the drawbar nut. It is built for CNC sliding-head lathes and Swiss-type machines that need sub-micron grip repeatability. Every collet is machined from hardened steel, ground to a 0.005 mm total runout, and shipped with a matching spanner wrench set that fits the collet’s external slots precisely.
Standard collets compress unevenly under high spindle speeds, causing bar vibration and surface finish defects. Our auto lathe collet uses a 16-slit design with a 0.3 mm wall thickness at the gripping zone. That geometry allows uniform radial compression across the full clamping length. The spanner wrench set is machined to a 0.02 mm clearance fit on the collet’s drive flats, so you can torque the drawbar nut without distorting the collet body. Result: 0.005 mm TIR at 8,000 RPM, and no slippage even when cutting 304 stainless steel at 0.15 mm feed per revolution.
We offer two material grades. For general-purpose bar work, we use AISI 4140 steel, hardened to HRC 50-55. For high-volume production with abrasive materials like Inconel or titanium, we use AISI 8620, carburized to a case depth of 0.8 mm and hardness of HRC 58-60. Both grades are cryogenically treated at -120°C for 4 hours after hardening. That step removes retained austenite, which is the main cause of dimensional drift during long production runs. Each collet is then ID-ground and OD-ground in a single setup, so the bore taper and the outer locating diameter are concentric within 0.003 mm.
The included spanner wrenches are not stamped or laser-cut. They are CNC milled from 45# steel, then hardened to HRC 40-45. The pin ends are ground to a 1.5 mm radius, matching the collet’s drive slots exactly. You get two wrenches: one for the collet nut, one for the collet body. The wrench handles are 150 mm long, giving you 2x mechanical advantage over standard collet wrenches. That means you can achieve the recommended 25 Nm clamping torque with less hand force, reducing operator fatigue and preventing over-tightening damage.
This collet set covers the most common auto lathe spindle sizes. Available bore diameters: 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 25, and 32 mm. Each collet has a 42 mm outer diameter and a 70 mm overall length, which fits standard DIN 6499 ER32 and ER40 collet chucks. The spanner wrench set is sized to match the collet’s external hex, so you do not need to buy separate wrenches for different collet sizes. If you use a non-standard spindle, we can machine the collet’s back end to your exact thread pitch and drawbar design within 5 working days.
| Specification | Value | Notes |
|---|---|---|
| Material grade | AISI 4140 or 8620 | 8620 for abrasive materials |
| Hardness (working zone) | HRC 50-55 (4140) / HRC 58-60 (8620) | Cryogenic treated at -120°C |
| Collet bore diameters | 1 - 32 mm | 16 standard sizes |
| Total indicated runout (TIR) | 0.005 mm | Measured at 3 mm from collet nose |
| Surface finish (bore) | Ra 0.2 µm | ID-ground after hardening |
| Surface finish (OD) | Ra 0.4 µm | Centerless ground |
| Slit count | 16 slits | 0.3 mm wall at grip zone |
| Clamping range per collet | ±0.15 mm | Standard ER-style elastic range |
| Spanner wrench hardness | HRC 40-45 | CNC milled from 45# steel |
| Lead time | 15 days (standard sizes) | 5 days for custom back-end thread |
| MOQ | No MOQ | Single piece accepted |
Every collet set goes through a 5-step inspection protocol. First, we check the bore diameter with an air gauge (0.002 mm resolution). Second, we measure TIR on a precision mandrel at three positions along the bore. Third, we verify the slit width with a feeler gauge — each slit must be 0.5 mm ± 0.05 mm. Fourth, we test the spanner wrench fit on a master collet. Finally, we run a sample clamp test on a 6 mm ground bar, measuring the bar’s deflection after 10 open-close cycles. Only sets that pass all five checks get the BQUQ lot number stamped on the collet face. You can trace every part back to its raw material batch and heat treatment furnace record.
Each collet is individually wrapped in VCI (vapor corrosion inhibitor) paper, then placed in a fitted foam insert inside a rigid cardboard box. The spanner wrenches are oiled and wrapped separately to prevent them from scratching the collet’s ground surfaces. The box is labeled with the part number, lot number, and TIR measurement certificate. For orders over 20 pieces, we use a wooden crate with internal foam partitions. Shipping is via DHL or FedEx Express from our Dongguan factory. Standard delivery to the US or Europe takes 4-6 business days. We declare the value accurately for customs, and we provide full tracking numbers within 24 hours of dispatch.
Start with your bar stock diameter. The collet bore should be 0.05-0.10 mm larger than the bar’s nominal size. For example, a 6.00 mm bar uses a 6.05 mm collet bore. Next, check your spindle’s drawbar thread. Most Japanese and German auto lathes use either a 16x1.5 or 20x1.5 thread. Our standard collets have a 20x1.5 thread, but we can change it to any pitch for free. Third, consider the material you are cutting. If you machine soft brass or aluminum, the 4140 grade is sufficient. If you cut hardened steel or superalloys, go with the 8620 grade. For a detailed breakdown of tooling selection, refer to our CNC cutting tool selection guide.
No MOQ — you can order a single collet with spanner wrench set, and we will treat it with the same priority as a bulk order.
Yes, we can modify the back-end thread, overall length, or front nose profile within 5 working days, at no extra cost for thread changes.
We grind the bore and OD in one setup on a CNC cylindrical grinder, then verify each piece with an air gauge and mandrel check before packing.
Standard sizes ship in 15 days from order confirmation; custom back-end thread adds 5 days, and shipping takes 4-6 business days via DHL.
A well-maintained auto lathe collet should last for 50,000 to 100,000 clamping cycles. The first sign of wear is usually a burr on the slit edges, which causes the collet to stick in the chuck. We recommend cleaning the collet with an air blow every 500 cycles and re-oiling the slits with a light machine oil. When the TIR exceeds 0.015 mm, send the collet back to us. We can re-grind the bore and re-cut the slits for about 40% of the new part cost. This service takes 10 days and restores the collet to its original 0.005 mm TIR. For more on how to maintain precision in your machining process, see our CNC machining tolerances guide.
We are a precision manufacturing factory in Dongguan, China, with 20 years of CNC machining experience. We do not pay licensing fees or brand markups. The cost of this CNC Machined Auto Lathe Collet With Spanner Wrench Set is $18-$35 per set, depending on size and material grade. That price includes the collet, two spanner wrenches, the TIR certificate, and the VCI packaging. Compare that to a European-brand collet at $60-$90 per set, and you save 60% while getting the same or better runout. The only difference is the name on the box. For a deeper comparison of machining strategies that affect your cycle time and tool life, read our CNC programming optimization guide.
We are a precision manufacturing partner, not just a supplier. Every collet is made in China at our Dongguan factory, under the same roof where we produce heat sinks, springs, and stamped parts for automotive and medical clients. We know that a collet failure stops your entire line, so we over-inspect, not under-price. If you are tired of inconsistent collets from trading companies, try a factory-direct order. Send your drawing or just your spindle specs. We will respond with a firm quote within 12 hours — including the TIR we guarantee, the hardness we will deliver, and the exact shipping date.
Request your quote today: email sc@bquq.com or WhatsApp +86 13713157787. Send your drawing, and we will confirm the collet size, thread pitch, and price within 12 hours. No MOQ, no middleman, no surprises.
| 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 |
