This is a 52 Type Hex Bore Spring Collet, machined on CNC auto lathes from hardened steel. It grips hexagonal bar stock (sizes from 4 mm to 20 mm across flats) with 0.005 mm total runout and repeatabi
This is a 52 Type Hex Bore Spring Collet, machined on CNC auto lathes from hardened steel. It grips hexagonal bar stock (sizes from 4 mm to 20 mm across flats) with 0.005 mm total runout and repeatability of ±0.003 mm. You get a rigid, wear-resistant collet that holds hex material without marking, and we ship standard sizes in 7 days from our Dongguan factory.
Round collets crush hex corners. That creates stress points and dimensional drift. Our hex bore matches the workpiece shape exactly, spreading clamping force evenly across all six flats. Result: you hold 0.005 mm TIR at 6000 RPM, and you eliminate bar slip during heavy turning passes. The bore is wire-cut then honed to Ra 0.4 µm, so the grip is both strong and smooth.
We start with 20CrMnTi alloy steel, carburized to a case depth of 0.8-1.2 mm. Core hardness is HRC 58-60; surface hardness reaches HRC 60-62. This gives the collet a tough core that absorbs shock and a hard shell that resists abrasive wear from hex bar edges. We do not use case-hardened mild steel — that chips. You get a collet that runs 200,000+ cycles before needing a re-grind.
Three slots are cut by wire EDM, not milled. Slot width is 0.8 mm, with a 0.2 mm radius at the slot root to prevent stress cracking. The slot pattern is engineered so the collet closes concentrically — no one-sided pinching. We measure closing force on a calibrated fixture: every collet must show less than 0.005 mm radial deviation when compressed from 20 mm to 19.5 mm.
We cut hex bores for across-flat sizes 4, 5, 6, 8, 10, 12, 14, 16, 18, and 20 mm. Tolerance on the across-flat dimension is +0.01 / -0.00 mm. The bore is oriented to the collet’s taper within 0.005 mm total runout. If you need an odd size like 7.5 mm or 11 mm, we machine it — no extra tooling cost, just a 3-day lead time extension.
Every collet goes through a 5-point inspection. We check hex bore size with an optical comparator (0.001 mm resolution), taper angle with a CMM, runout on a precision mandrel, hardness on a Rockwell tester, and surface finish with a profilometer. We send you a digital inspection report with photos of the actual measurements. No random sampling — 100% inspection on every unit.
|| Material | 20CrMnTi alloy steel, carburized |
| Surface Hardness | HRC 60-62 (case depth 0.8-1.2 mm) |
| Core Hardness | HRC 58-60 |
| Hex Bore Range | 4 mm to 20 mm across flats |
| Bore Tolerance | +0.01 / -0.00 mm |
| Runout (TIR) | 0.005 mm |
| Surface Finish (Bore) | Ra 0.4 µm |
| Slot Width | 0.8 mm, EDM cut |
| Closing Range | 0.5 mm total (e.g., 20 mm to 19.5 mm) |
| Lead Time | 7 days for standard sizes, 10 days for custom |
| MOQ | No MOQ — order 1 piece or 1000 pieces |
The 52 Type refers to the spindle taper size for common auto lathes (e.g., Tornos, Citizen, Star). The taper angle is 30 degrees, and the locating diameter is 52 mm. You mount it directly into the spindle nose. It uses a standard drawbar thread of M16 x 1.5. We also offer a backup ring and pusher tube for longer bar feed-out. If you are not sure about fit, send us your machine model and we will confirm within 24 hours.
No MOQ — order one collet for testing or a full production set; pricing is the same per unit.
Yes, we machine any hex size between 4 mm and 20 mm, with a 3-day lead time extension for custom bores.
Every collet, regardless of order size, gets the same CMM and optical comparator inspection, and you receive the inspection report.
Standard sizes ship in 7 days; custom hex bores ship in 10 days from drawing approval.
For better tool life and surface finish, pair this collet with the right cutting parameters. Read our CNC cutting tool selection guide for material-specific speeds and feeds. If you are pushing cycle times, our CNC programming optimization guide shows how to reduce idle time. For general tolerance understanding, check the CNC machining tolerances guide.
We are a precision manufacturing factory in Dongguan, China, with 20 years of CNC machining, stamping, springs, and heat sink production. This collet is 100% made in China, and we export worldwide. Send us your drawing or your machine model, and we will quote firm within 12 hours.
Email your drawing to sc@bquq.com or WhatsApp +86 13713157787. Get your firm quote within 12 hours, with no MOQ and 7-day lead time.
| 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 |
