This is a CNC machined ER32 spring collet chuck designed specifically for reaming tools in CNC spindles. It grips the reamer shank with 0.005 mm TIR runout, holds hardness at 58–62 HRC, and ships from
This is a CNC machined ER32 spring collet chuck designed specifically for reaming tools in CNC spindles. It grips the reamer shank with 0.005 mm TIR runout, holds hardness at 58–62 HRC, and ships from our Dongguan factory in 15 days. You get a tool holder that eliminates reamer wobble, extends tool life, and improves hole finish to Ra 0.4 µm without paying a premium for imported brands.
Reamers cut with multiple edges along the full flute length. Any radial deflection—even 0.01 mm—causes oversized holes, chatter marks, and premature edge wear. A standard drill chuck allows micro-movement under lateral load. Our ER32 spring collet chuck compresses the collet evenly around the shank using a tapered nut, creating a 360° grip. This distributes clamping force uniformly, locking the reamer axially and radially. The result: consistent hole size within IT7 grade and no bell-mouthing at the entry.
We machine the chuck body from 42CrMo steel, then grind the taper seat to a 8° included angle. The collet pocket is held to 0.003 mm roundness. When you insert an ER32 collet (sold separately or we supply), the spring slots collapse evenly onto the reamer shank. For reamers with h6 tolerance shanks, the grip is rigid enough to handle torque up to 120 Nm. We also offer a through-coolant variant with a center hole for high-pressure coolant delivery to the cutting zone—critical for deep-hole reaming in aluminum or steel.
We start with 42CrMo (AISI 4140) bar stock. After CNC turning and milling, we carburize the body to a case depth of 0.8–1.2 mm, then harden and temper to 58–62 HRC. This gives a wear-resistant surface on the taper and threads while retaining a tough core that absorbs vibration. The nut is made from 20CrMnTi, carburized to the same hardness. All critical surfaces—the taper, the nut threads, and the collet seat—are finish ground after heat treatment to remove distortion. Surface finish on the taper is Ra 0.2 µm, ensuring smooth collet seating and repeatable clamping force.
Runout is not a single measurement; it is the sum of errors in the spindle taper, the chuck body, the collet, and the reamer shank. We control our contribution by grinding the ER32 taper and the external locating diameter in one setup on a cylindrical grinder. This co-axiality is verified on a CNC tool presetter with a 0.001 mm resolution. We then test each chuck with a master ER32 collet and a 20 mm test bar, measuring TIR at 3 mm from the collet nose. We reject anything above 0.005 mm. Our production average is 0.003 mm.
Every ER32 chuck goes through a three-step check. First, a dimensional inspection: taper angle with a sine bar, thread pitch with a go/no-go gauge, and hardness with a Rockwell tester. Second, a functional test: we mount the chuck on a test arbor, load a standard reamer, and measure runout at the nose and at 50 mm extension. Third, a visual inspection under a magnifier for edge burrs or grinding burns. We record the actual runout value on the test certificate that ships with each unit. If you request it, we send you the video of the runout test before packing.
| Specification | Value |
|---|---|
| Collet type | ER32 (ISO 15488) |
| Shank diameter options | 19.05 mm (¾") straight, 20 mm, 25 mm, or custom |
| Body material | 42CrMo (AISI 4140), carburized and hardened |
| Hardness (body and nut) | 58–62 HRC |
| Taper seat angle | 8° included, ground |
| Runout (TIR at nose) | 0.005 mm max (average 0.003 mm) |
| Surface finish on taper | Ra 0.2 µm |
| Clamping range | 2 mm to 20 mm (via ER32 collets) |
| Max torque capacity | 120 Nm with h6 shank reamer |
| Standard lead time | 15 days after drawing approval |
| MOQ | No MOQ—single piece accepted |
| Inspection certificate | Included with each unit |
If you ream holes deeper than 3x diameter, chip evacuation becomes the bottleneck. Coolant starvation causes built-up edge and poor finish. We offer a variant with a 4 mm center coolant hole, sealed by O-rings at the collet seat. This delivers coolant directly to the cutting edge at pressures up to 70 bar. The coolant hole does not weaken the body because we position it inside the neutral axis of the taper. You can order this option without any change to the external dimensions or the runout spec.
Standard chucks fit BT30, BT40, CAT40, or HSK spindles via an adapter. But many CNC reaming jobs use straight-shank holders in a Weldon or side-lock holder. We can machine the chuck body with a flat for set-screw locking, a keyway for torque transmission, or a custom thread for a drawbar. Tell us your spindle nose type and drawbar thread pitch. We will modify the body design in CAD, send you a 3D PDF for approval, then machine to that spec. No extra cost for small changes like chamfer size or thread depth.
With our chuck holding a sharp carbide reamer at 0.005 mm runout, you can expect hole surface finish of Ra 0.4–0.8 µm in steel (e.g., 4140) and Ra 0.2–0.4 µm in aluminum. Hole oversize is typically within 0.005–0.010 mm of the reamer diameter. This eliminates the need for a separate honing operation on most production parts. If you need tighter tolerances, our CNC machining tolerances guide explains what is achievable with different tooling and machine conditions.
Selecting the right collet size and tightening torque is the other half of the equation. A worn or mismatched collet ruins even a perfect chuck. Read our CNC cutting tool selection guide for a comparison of ER vs. TG vs. hydraulic chucks in reaming applications.
Each chuck is individually wrapped in anti-rust paper, placed in a fitted plastic box, and packed in a foam-lined carton. We ship via DHL, FedEx, or UPS—door-to-door in 3–5 days to most countries. For large orders, we use air freight or sea freight, depending on your urgency. We have exported to 40+ countries over the past 20 years, and we handle customs documentation ourselves. You receive a tracking number within 24 hours of shipment.
No MOQ—we accept a single piece order for testing or prototyping, and you pay the same unit price as for 50 pieces.
Yes, we machine custom shanks (any diameter from 16 mm to 32 mm), add flats, keyways, or center coolant holes, and modify the thread pitch to match your drawbar—all with no design fee.
We test each chuck with a master collet and a 20 mm test bar on a presetter, record the TIR value, and include the measurement certificate in the shipment.
Standard chucks ship in 15 days; custom shank or coolant variants take 20–25 days, including drawing approval and sample inspection.
Send us your reamer shank diameter, spindle type, and required hole tolerance. We will reply with a firm quote within 12 hours. Email sc@bquq.com or WhatsApp +86 13713157787. Send your drawing in STEP, IGES, or PDF—we will confirm the design and pricing the same day. BQUQ precision manufacturing, made in China, with no MOQ and no hidden charges.
| 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 |
