This is a complete CNC machined ER collet chuck tool kit with milling drill tools, built for shops that need tool holding accuracy without paying a premium. The chuck body is machined from 42CrMo stee
This is a complete CNC machined ER collet chuck tool kit with milling drill tools, built for shops that need tool holding accuracy without paying a premium. The chuck body is machined from 42CrMo steel, hardened to HRC 58-62, with a guaranteed TIR (runout) of 0.005 mm at the nose. We ship standard ER20 and ER32 kits in 10 days, and because we are a precision manufacturing factory in Dongguan, China, you get the same quality as German or Japanese holders at 30-40% lower cost.
ER collet chucks use a tapered collet that compresses evenly around the tool shank when you tighten the lock nut. The key is the 8° cone angle inside the chuck body — if that angle is off by even 0.1°, you get uneven grip and runout. We grind the taper in-house on a Studer S41, holding the angle to ±0.002 mm. That is why our TIR stays at 0.005 mm, not the 0.015 mm you see from cheaper suppliers. The kit includes precision ER collets in 1 mm increments, so your milling drill tools seat dead-center every time.
Our chuck body starts as 42CrMo alloy steel — the same grade used in automotive drivetrain gears. We pre-machine, then vacuum harden to HRC 58-62, not the HRC 48-52 you find in import holders. After hardening, we temper once to relieve stress, then precision grind the bore and taper. The lock nut is 20CrMnTi case-hardened to HRC 60 ± 2, with a bearing surface that is lapped to Ra 0.4 µm. You will not see scale, decarb, or soft spots because we control the furnace atmosphere with carbon potential sensors.
This is a ready-to-run kit, not just a single chuck. You get: 1 ER collet chuck body (choose ER20 or ER32), 10 precision collets in sizes 1-10 mm (ER20) or 2-20 mm (ER32), 1 hardened lock nut with spanner holes, 1 C-spanner wrench, and 1 draw bar if you order the BT40 or BT30 shank version. For milling drill tools, we also include a set of 3 ER collet wrenches (torque-rated) and a cleaning brush. Every collet is individually measured for TIR before packing — we reject anything above 0.005 mm.
We do not do batch sampling. Every single CNC machined ER collet chuck tool kit with milling drill tools goes through a 3-stage inspection. First, a CMM (Zeiss Contura) checks the taper angle, bore diameter, and concentricity. Second, a runout gauge checks TIR at 3 positions: collet nose, 10 mm from nose, and 50 mm from nose. Third, we torque-test the lock nut to 50 Nm and verify the collet closes without sticking. You get a signed inspection report with each order, including the measured TIR value — not a generic "passed" sticker.
| Parameter | Value |
|---|---|
| Material (chuck body) | 42CrMo alloy steel |
| Hardness (chuck body) | HRC 58-62 |
| Hardness (lock nut) | HRC 60 ± 2 (20CrMnTi) |
| TIR (runout) at nose | 0.005 mm max |
| Taper angle accuracy | ±0.002 mm (8° cone) |
| Surface finish (taper bore) | Ra 0.4 µm |
| Collet sizes (ER20 kit) | 1-10 mm (10 pcs) |
| Collet sizes (ER32 kit) | 2-20 mm (10 pcs) |
| Shank options | BT30, BT40, BT50, HSK63, straight shank |
| Lead time | 10 days (standard kits), 15 days (custom shank) |
| MOQ | No MOQ — order 1 kit or 100 |
| Inspection report | Included with every shipment |
Most ER chucks advertise 0.010-0.015 mm TIR. That is because they grind the taper in a separate operation and then bolt the nose on, introducing stack-up error. We machine the taper and the bore in one clamping operation on a 5-axis Mazak, so there is zero re-clamping error. The result is 0.005 mm TIR, which directly improves your milling drill tools' surface finish and tool life. If you are doing finishing passes in aluminum or steel, you will see the difference in the first part — no chatter marks, no rework. For a deeper look at tool selection, read our CNC cutting tool selection guide.
We stock BT30, BT40, BT50, HSK63, and straight shank versions. If your spindle uses Capto or a proprietary taper, send us your drawing and we will machine the shank to match — no extra tooling charge for the first 10 units. The kit is a precision manufacturing product made in China, but we do not cut corners on the shank: it is ground to AT3 grade (ISO 1947), which means a taper error of less than 0.005 mm over the full gauge length. For custom lengths, we can extend the shank up to 150 mm without affecting TIR.
Each kit ships in a foam-lined steel case that protects the collets and chuck from impact. We use anti-rust VCI paper inside the case, so the parts arrive clean and ready to mount — no need to degrease before first use. For international orders, we ship via DHL or FedEx (2-5 days) or by sea freight (15-25 days) if you are ordering in volume. The case is 320 x 220 x 120 mm and weighs 3.8 kg (ER20 kit) or 5.2 kg (ER32 kit), so shipping cost is predictable. We mark the package as "precision tooling" with a low-value commercial invoice to avoid customs delays.
No MOQ — you can order a single CNC machined ER collet chuck tool kit with milling drill tools as a trial, and we will still give you the same inspection report and packaging as a bulk order.
Yes, we can change the collet sizes (e.g., all metric or all imperial) and machine any shank taper, length, or pull stud configuration — just send your drawing and we will quote within 12 hours.
For custom kits, we produce a first article and send you a CMM report and photos before mass production; if the first article does not pass your tolerance, we remake it at no cost — see our CNC machining tolerances guide for what we can hold.
Standard ER20 and ER32 kits ship in 10 days; custom shank or custom collet ranges take 15 days because we need to source the raw material and program the grind cycle.
Get a firm quote within 12 hours. Send your drawing or just your spindle type and collet range — we will reply with pricing, lead time, and a technical drawing of the chuck. Email sc@bquq.com or WhatsApp +86 13713157787. No MOQ, no design fee for standard kits, and we ship worldwide from our Dongguan factory.
| 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 |
