This is a CNC machined ER40 spring collet chuck built for precision CNC lathes. It grips tool shanks or workpieces with 0.005 mm total indicated runout (TIR), holds 58-60 HRC hardness, and ships in 7
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This is a CNC machined ER40 spring collet chuck built for precision CNC lathes. It grips tool shanks or workpieces with 0.005 mm total indicated runout (TIR), holds 58-60 HRC hardness, and ships in 7
This is a CNC machined ER40 spring collet chuck built for precision CNC lathes. It grips tool shanks or workpieces with 0.005 mm total indicated runout (TIR), holds 58-60 HRC hardness, and ships in 7 days from our Dongguan factory. You get repeatable clamping force without marring your tooling, backed by 20 years of precision manufacturing experience.
The ER40 collet system uses a tapered sleeve that collapses evenly around the tool shank. Our chuck body is machined from a single billet of 42CrMo alloy steel on a 5-axis CNC lathe, then ground to a concentricity of 0.003 mm between the taper seat and the back taper. When you torque the nut to 120 Nm, the collet compresses uniformly, holding round bars from 3 mm to 26 mm diameter without the wobble you get from set-screw holders.
We verify every chuck on a precision air gauge. The max TIR at the nose is 0.005 mm, measured 40 mm from the collet face. This is consistent across the full ER40 range—not just a single test piece. For comparison, standard chucks from catalogs often run 0.015 mm or worse. That 0.01 mm difference is the gap between a good finish and a scrapped part on a tight-tolerance job.
We start with 42CrMo (AISI 4140) round bar, not castings or forgings with hidden porosity. After rough turning, we harden and temper to 58-60 HRC. This gives the chuck body the stiffness to resist deflection under heavy cuts—up to 80% of the spindle torque without measurable flex.
The collet nut is case-hardened to 60-62 HRC with a black oxide finish for corrosion resistance. The internal threads are rolled, not cut, which increases fatigue life by 30% compared to cut threads. Every chuck is cryogenically treated at -120°C to stabilize the microstructure, preventing dimensional drift over years of use.
We also offer a stainless steel variant (17-4PH) for medical or food-grade applications. It holds the same 0.005 mm TIR but resists rust from coolant or washdowns. Tell us your material requirement in the drawing, and we'll adjust the heat treat cycle accordingly.
This chuck accepts standard ER40 collets from any reputable brand—not just our own. The taper angle is 8° per side, matching the DIN 6499 standard. You can use our chuck with your existing ER40 collet set, which saves you money and avoids inventory duplication.
Capacity is a full 26 mm maximum, with collets available in 1 mm increments from 3 mm to 26 mm. For metric or inch shanks, we machine the back taper to fit your spindle nose—options include A2-4, A2-5, A2-6, or straight shank with keyway. We also make custom back plates with pilot bores for specific lathe models.
If you need a collet chuck for a Swiss-type lathe or a multi-spindle machine, our engineering team will match the pull-back distance and thread pitch to your machine's draw tube. Send us your spindle drawing, and we'll confirm fitment within 24 hours.
The chuck body and nut are ground to Ra 0.4 µm on all functional surfaces. This low roughness reduces friction between the collet and the taper, so you get consistent clamping force even after thousands of cycles. We measure surface finish with a profilometer on every part, not just a random sample.
For high-volume production or abrasive materials like cast iron, we offer a TiN (titanium nitride) coating on the nut and taper. This adds a 3 µm layer that reduces wear by 50% and prevents galling when you swap collets frequently. Coated chucks are standard for automotive and aerospace lines that run 24/7.
If you prefer a non-reflective finish for optical alignment or reduced glare in manual lathe work, we can apply a matte black oxide. This is a no-cost option and does not affect dimensional accuracy.
Every ER40 chuck goes through a 12-point inspection before it leaves our factory. We use a Federal air gauge to measure TIR at the nose, a Rockwell tester for hardness, and a thread plug gauge for the nut. If any point fails, the chuck is scrapped, not reworked.
We also test each chuck with a real ER40 collet and a 10 mm test bar. The bar must spin without detectable vibration at 3,000 RPM on our test lathe. This simulates your actual working conditions, so you know the chuck will perform on your machine, not just on paper.
You receive a signed inspection report with every order. This includes the measured TIR, hardness, and a photo of the test setup. This is our standard for all CNC machining products, whether you order one piece or a thousand.
Standard ER40 chucks (A2-5 or A2-6 back taper) ship in 7 days from order confirmation. Custom back plates, special coatings, or stainless steel variants take 15 days. We keep a buffer stock of 42CrMo billets and ER40 collets, so we never wait on raw material.
Shipping is via DHL or FedEx, with a typical transit time of 3-5 days to North America or Europe. We provide a tracking number the moment your order leaves the factory. For urgent jobs, we offer a 48-hour express service at a 15% surcharge—call us to confirm availability before ordering.
We are a made in China factory with direct export experience. No middlemen, no trading company markups. Your inquiry goes straight to our engineering and production team in Dongguan.
| Parameter | Value |
|---|---|
| Material (Standard) | 42CrMo (AISI 4140) alloy steel |
| Material (Optional) | 17-4PH stainless steel |
| Hardness (Body) | 58-60 HRC |
| Hardness (Nut) | 60-62 HRC, case-hardened |
| Total TIR (at nose) | 0.005 mm max |
| Concentricity (taper seat) | 0.003 mm |
| Surface Finish (functional) | Ra 0.4 µm |
| Collet Standard | DIN 6499 / ISO 15488 |
| Capacity Range | 3 mm to 26 mm |
| Back Taper Options | A2-4, A2-5, A2-6, straight shank |
| Torque Requirement | 120 Nm on nut |
| Lead Time (standard) | 7 days |
| Lead Time (custom) | 15 days |
| MOQ | No MOQ—single piece accepted |
Yes, there is no MOQ—we accept single-piece orders for prototyping or evaluation, and you pay the same unit price as a bulk order.
Email your 2D or 3D file (STEP, IGES, or PDF) to sc@bquq.com, and our engineers will confirm fitment and quote within 12 hours.
Each chuck gets a 100% air gauge TIR check, Rockwell hardness test, and a live test with a 10 mm bar at 3,000 RPM; the signed report ships with the product.
Quotes are sent within 12 hours, standard chucks ship in 7 days, and express 48-hour delivery is available for urgent orders.
Before you finalize your tooling setup, read our CNC cutting tool selection guide to match this chuck with the right inserts and holders. For tighter tolerances on your workpiece, check our CNC machining tolerances guide to set realistic specs for your next order.
Get a firm quote within 12 hours. Email your drawing to sc@bquq.com or message us on WhatsApp at +86 13713157787. We respond to every inquiry within one business hour, even on weekends. Send your drawing today, and we'll confirm machining cost, lead time, and shipping options immediately.
| 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 |
