This is a CNC machined Auto Lathe 15 Type Hex Bore Spring Collet designed for gripping hexagonal bar stock in automatic lathes and CNC turning centers. It delivers 0.005 mm TIR runout, a hardness of H
This is a CNC machined Auto Lathe 15 Type Hex Bore Spring Collet designed for gripping hexagonal bar stock in automatic lathes and CNC turning centers. It delivers 0.005 mm TIR runout, a hardness of HRC 58-60, and a surface finish of Ra 0.4 µm—all from our Dongguan factory with a 15-day standard lead time.
The bore geometry is precision broached to match 15 Type hex sizes (e.g., 4 mm, 6 mm, 8 mm, 10 mm across flats). Unlike round collets that crush hex corners, this design applies uniform radial force on the flats. You get zero slippage under 5,000 RPM and no mark-off on finished parts. Each collet is slotted with a 0.3 mm relief cut, allowing 0.1 mm clamping range per size.
We start with 65Mn spring steel or 9SiCr alloy tool steel—both chosen for fatigue resistance in high-cycle clamping. The heat treatment is a two-step process: quench at 860°C, then temper at 400°C for 90 minutes. Final hardness lands between HRC 58-60, with a case depth of 1.2 mm. This gives you 200,000+ clamping cycles without losing spring-back force.
Most collet failures come from shank misalignment, not the bore. We grind the 15 Type taper (30° included angle) and the bore in one clamping setup. The result: 0.005 mm TIR at the bore mouth and 0.008 mm TIR at 20 mm depth. We also laser-engrave the size and batch number on the flange so you can trace the grind date.
Every collet passes a 3-point check: bore gauge for hex flat-to-flat dimension (±0.01 mm), a CMM scan of the taper angle (±0.5°), and a live runout test on a test arbor. We attach a signed inspection report with the batch number. If you need a full material certificate (EN 10204 3.1), we provide it at no extra cost.
For tooling selection beyond collets, see our CNC cutting tool selection guide. To understand how these tolerances fit your part design, check our CNC machining tolerances guide.
| Specification | Value |
|---|---|
| Product Type | Auto Lathe 15 Type Hex Bore Spring Collet |
| Available Hex Sizes | 4, 5, 6, 7, 8, 9, 10, 12 mm (across flats) |
| Material Grades | 65Mn, 9SiCr, or 42CrMo (customer choice) |
| Hardness (After Tempering) | HRC 58-60 |
| Runout (TIR at Bore) | 0.005 mm |
| Surface Finish | Ra 0.4 µm (ground bore and taper) |
| Size Tolerance (Hex Flats) | ±0.01 mm |
| Clamping Range per Size | 0.1 mm |
| Standard Lead Time | 15 days (stock sizes: 7 days) |
| MOQ | No MOQ—order 1 piece or 1,000 |
Standard JIS B 6151 collets allow 0.01 mm runout. We grind to 0.005 mm because we use a Studer S33 cylindrical grinder with in-process gauging. The operator adjusts for wheel wear every 50 pieces, not every shift. This is precision manufacturing made in China at a cost you can justify—about 20% below Japanese equivalents.
Each collet is individually wrapped in VCI (vapor corrosion inhibitor) paper, then placed in a foam-lined plastic box. For orders above 50 pieces, we use a wooden crate with silica gel packs. This prevents rust even if the container sits at the port for 6 weeks. We label the outside with the part number, size, and heat batch for easy warehouse sorting.
No MOQ—we will make a single custom collet for your prototype run, but the tooling fee for a non-standard hex size is $50.
Yes, we can change the bore depth, taper angle (from 30° to 45°), or add a coolant hole, but these changes may add 3-5 days to the lead time.
We use SPC (statistical process control) on the bore dimension every 20 pieces and perform a 100% runout check on a test arbor before packing.
Repeat orders for the same size and material ship in 10 days, and we keep a 200-piece stock of the most common sizes (6 mm, 8 mm, 10 mm) for 5-day dispatch.
Send us your drawing or a simple sketch with the hex size and bar stock tolerance. We will reply with a firm quote within 12 hours, including a CAD preview of the collet profile. For urgent needs, message us on WhatsApp. We handle export paperwork, and our prices are FOB Shenzhen or CIF your port.
Email: sc@bquq.com
WhatsApp: +86 13713157787
| 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 |
