What This BT30 ER Collet Chuck Does to Your Spindle’s Accuracy This is a CNC machined BT30 ER collet chuck tool holder designed for your CNC spindle’s BT30 taper interface. It grips ER collets from ER
This is a CNC machined BT30 ER collet chuck tool holder designed for your CNC spindle’s BT30 taper interface. It grips ER collets from ER16 to ER32, holding cutting tools with a guaranteed TIR (total indicated runout) of 0.005 mm or less at the collet nose. That translates to repeatable tool centering, fewer rejected parts, and a measurable drop in surface finish variation across your batch—typically from Ra 1.6 µm down to Ra 0.8 µm on aluminum and steel.
We machine the taper and collet seat in one setup on a 5-axis Mazak, so the geometry stays true to the BT30 standard (MAS-403 BT). The result is a holder that seats into your spindle with zero wobble, pulls collets tight without distortion, and holds drills, end mills, and reamers firmly even at 12,000 RPM. Lead time for standard sizes is 15 days; custom lengths and special shank options add 3–5 days.
ER collet chucks work by squeezing a slotted collet around the tool shank. The BT30 body’s internal cone angle (8° per side) matches the ER collet’s external taper. When you tighten the lock nut, the collet compresses evenly, gripping the tool along its full contact length—not just at two points like set-screw holders.
Our BT30 ER chucks are machined with the collet seat and internal thread in a single clamping operation. This eliminates the common error of misaligned threads that cause uneven collet compression. We also grind the nose diameter after heat treatment to hold concentricity between the collet pocket and the BT30 taper within 0.003 mm. That’s why our runout spec is 0.005 mm at 4×D from the nose, not just at the collet face.
For high-speed machining, we balance every holder to G2.5 at 20,000 RPM as standard. If you need higher, we can balance to G1.0 at 30,000 RPM for an extra 48 hours in production. This keeps vibration low, which directly extends tool life by up to 30% in our in-house tests.
We start with 20CrMnTi alloy steel (AISI 8620 equivalent) for the body and the lock nut. This grade gives us a tough core after carburizing—surface hardness reaches HRC 58–60, while the core stays at HRC 35–40 to absorb shock without cracking. For the collet seat, we apply a separate nitriding step to achieve HRC 62–64 on the wear surface only, which reduces friction when you insert and remove tools.
All critical surfaces—the BT30 taper, the collet pocket, and the thread flanks—are ground after heat treatment. Grinding removes decarburized layers and leaves a surface finish of Ra 0.4 µm on the taper, Ra 0.8 µm on the collet seat, and Ra 1.6 µm on the external body. We do not use a black oxide coating unless you request it; bare ground steel gives the best dimensional stability for high-precision work.
Lock nuts are made from 40Cr steel (AISI 5140), hardened to HRC 48–52. They are knurled for a sure grip, and we machine a precision groove for a standard C-spanner. The nut’s thread pitch is M18×1.5 for ER16, M25×1.5 for ER25, M32×1.5 for ER32—all compatible with generic ER collets, so you are not locked into a proprietary system.
Every single BT30 ER collet chuck goes through a 4-point inspection before packing. First, we check the BT30 taper with a calibrated air gauge—acceptance limit is 0.002 mm straightness along the taper. Second, we mount the holder on a test mandrel and measure runout at the collet nose and at 100 mm from the nose using a 0.001 mm resolution dial indicator. Third, we torque a test ER collet with a 10 mm HSS end mill and re-measure runout under clamping load. Fourth, we check the thread fit with a go/no-go gauge to ensure the lock nut spins smoothly without binding.
Each holder gets a serial number etched on the flange. We keep the inspection data for 2 years, so if you ever have a problem, we can trace the batch, the machine operator, and the heat treatment furnace record. This traceability is part of our precision manufacturing process, not an afterthought.
We also sample-test every 50th piece for hardness on a Rockwell tester, confirming HRC 58–60 on the body and HRC 62–64 on the nitrided seat. If any sample fails, the entire batch is re-heat-treated and re-ground. You will never receive a holder that skips this step.
| Parameter | Specification |
|---|---|
| Taper type | BT30 (MAS-403 BT) with pull stud hole |
| Collet size options | ER16, ER25, ER32 |
| Gripping range | ER16: Ø1–10 mm; ER25: Ø1–16 mm; ER32: Ø2–20 mm |
| Body material | 20CrMnTi (AISI 8620 equivalent), carburized |
| Hardness (body surface) | HRC 58–60 |
| Hardness (collet seat, nitrided) | HRC 62–64 |
| Runout (TIR) at nose / at 100 mm | 0.005 mm / 0.010 mm |
| Surface finish (taper / seat / body) | Ra 0.4 / Ra 0.8 / Ra 1.6 µm |
| Balance grade (standard) | G2.5 @ 20,000 RPM |
| Standard lead time | 15 days for sizes in stock |
| MOQ | No MOQ—order 1 piece or 1000 |
We also offer custom pull stud lengths, extended neck versions for deep cavity work, and through-coolant holes (up to 70 bar) on request. Just send your drawing or a simple sketch with the critical dimensions, and we will confirm feasibility within 24 hours.
Many Chinese suppliers apply a black oxide or TiN coating to tool holders to make them look premium. We do not do this by default. Coatings add thickness—typically 0.005–0.010 mm—which can distort the tight tolerance on the BT30 taper and the collet seat. For standard steel and aluminum machining, bare ground steel is the most accurate choice.
However, if you are cutting composites, graphite, or highly abrasive materials, we can apply a hard chrome plating (0.003 mm max) to the external body only, never on the taper or seat. This increases wear resistance without affecting the fit. We also offer a phosphate coating for corrosion protection in humid shop environments—again, only on non-critical surfaces. Tell us your application, and we will recommend the right surface treatment.
For high-torque applications above 50 Nm, we recommend our ER32 version with a longer grip length. The ER32 collet has a 32 mm thread diameter and a 40 mm grip length, which reduces tool pull-out by 15% compared to ER25 in our lab tests. This is critical for roughing passes in stainless steel or Inconel.
Each holder is individually wrapped in anti-rust paper, placed in a foam-lined plastic box, and then packed in a corrugated carton with a minimum 5 cm foam padding on all sides. We ship via DHL, FedEx, or UPS—whichever you prefer—and the declared value is always the actual transaction value for customs clarity. For orders over 10 pieces, we can supply a wooden crate with silica gel packs for long-term storage.
Every shipment includes a packing list, a commercial invoice, and a Certificate of Conformance (CoC) stating the material grade, hardness, and runout measurements for the batch. If you need a full material test certificate (MTC) with heat number and chemical composition, we can provide it for an additional 24-hour delay. All documents are in English.
We have shipped to 40+ countries, including the US, Germany, Japan, and Australia. Our export packaging meets ISPM-15 for wood, and we handle all export customs clearance from our side. You only need to provide a valid delivery address and a phone number for the courier.
There is no MOQ—you can order a single piece for testing, and the unit price remains the same as for bulk orders.
Yes, we can machine extended neck versions up to 150 mm total length and add through-coolant holes up to 70 bar with a 2-day delay and a small setup fee.
We inspect every piece after final grinding and before packing, and we use shock-absorbing packaging that prevents deformation during transit.
Standard sizes ship in 15 days from order confirmation; if you need faster, we can expedite to 7 days for a 10% rush fee.
Send us your drawing or just your tool list—we will reply within 12 hours with a firm price per piece, a confirmed lead time, and a sample inspection report if you need one. We are a precision manufacturing factory in Dongguan with 20 years of CNC machining experience, and we do not subcontract your work.
Email your inquiry to sc@bquq.com or message us on WhatsApp at +86 13713157787. If you are comparing suppliers, ask us for a reference list of current BT30 users in your region. For a broader view on choosing between collet chucks and other holders, read our CNC cutting tool selection guide. And if you want to understand the tolerance limits we work to, our CNC machining tolerances guide explains the practical side of runout and surface finish. For cycle time improvements during programming, see our advanced toolpath strategy article.
All our BT30 ER collet chucks are made in China, and we ship worldwide with no MOQ. Send your drawing today, and we will confirm your quote before your coffee gets cold.
| 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 |
