This is a complete CNC machined 5C collet set in various sizes, built for lathe tooling workholding. Each collet holds round stock with 0.005mm (0.0002") runout at the nose, and t
BQUQ CNC Machined 5C Collet Set Various Sizes Lathe Tooling
This is a complete CNC machined 5C collet set in various sizes, built for lathe tooling workholding. Each collet holds round stock with ≤0.005mm (0.0002") runout at the nose, and the hardened steel bo
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This is a complete CNC machined 5C collet set in various sizes, built for lathe tooling workholding. Each collet holds round stock with ≤0.005mm (0.0002") runout at the nose, and the hardened steel body delivers 58-60 HRC for long service life. We ship standard sets in 7 days; custom size sets in 12 days, direct from our Dongguan factory.
How 5C Collets Lock Stock Tight Without Distortion
A 5C collet uses a tapered outer cone (exactly 10 degrees included angle) that seats into a matching spindle nose. When you pull the collet back with a drawbar, the taper squeezes the slotted segments inward. The result is a full 360-degree grip around the workpiece—not three points like a chuck. This design distributes clamping force evenly, so you can hold thin-walled parts with less than 0.02mm deformation. The slots are wire-cut, not milled, so the slit width stays consistent at 0.3mm across all sizes in the set.
Materials and Heat Treatment: Why 8620 Steel Beats Carbon Steel
Each collet in this set starts as a solid bar of AISI 8620 alloy steel. We choose 8620 over plain 1045 carbon steel because it case-hardens deeper and resists wear at the gripping surface. After CNC turning and slot cutting, we carburize at 925°C for 4 hours, then quench and temper to a final hardness of 58-60 HRC. The case depth is 0.8-1.0mm. We also black oxide the entire surface (MIL-DTL-13924) to prevent rust during storage and transport. The gripping bore is ground after hardening, not before, which is why we can hold that 0.005mm runout consistently.
Size Range and Grip Capacity: From 1mm to 32mm in One Box
This set covers the most common lathe tooling diameters. You get 24 collets per set: each 1mm step from 1mm to 13mm, plus 14, 15, 16, 18, 20, 22, 25, 28, 30, and 32mm. The gripping range per collet is +0.05mm to -0.05mm, so a 10mm collet holds 9.95mm to 10.05mm stock. For metric users, this is a full working range. If you need fractional inch sizes (1/16" to 1-1/4"), we can swap sizes at no extra cost—just tell us your list when you order.
Inspection Before Every Shipment: Runout and Hardness Checks
Every single collet in this set gets measured, not sampled. We use a Zeiss CMM to verify the taper angle (10° ± 0.05°) and a TIR gauge with a precision ground test bar to check nose runout. Hardness is tested on a Rockwell C scale at three points per collet. We also do a 100% visual check under 5x magnification for edge chips or burrs on the slots. A copy of the inspection report for your batch is included in the shipping box—you can trace the exact measured values for each collet.
Specification
Value / Detail
Material
AISI 8620 alloy steel (case-hardened)
Hardness
58-60 HRC (case depth 0.8-1.0mm)
Size range
1mm to 32mm (24 collets per set, 1mm steps)
Roundness tolerance
≤0.003mm on gripping bore
Runout (TIR at nose)
≤0.005mm (0.0002")
Taper angle
10° ± 0.05° included
Surface finish (bore)
Ra 0.4μm (ground)
Slot width
0.3mm (wire-cut)
Surface treatment
Black oxide (MIL-DTL-13924)
Lead time
7 days standard set, 12 days custom sizes
MOQ
No MOQ (single set accepted)
Packing
Wooden case with foam insert, 24 slots
Why 5C Beats ER Collets for Bar Work on a Lathe
ER collets are great for toolholders, but for lathe bar work, 5C has two advantages. First, 5C collets have a larger through-hole for the same outer diameter—you can feed bigger stock through the spindle. Second, the 5C taper is self-locking, so it won't release under heavy cutting force. ER collets rely on a threaded nut that can back off under vibration. If you are doing production turning, the 5C system minimizes downtime from re-tightening. For more on matching toolholders to your job, see our CNC cutting tool selection guide.
Custom Configurations: Split Sizes, Metric Only, or Inch Only
You do not have to buy the full 24-piece set. We can split the set into any combination—for example, only 6mm to 12mm for a small job shop, or add extra collets of a size you use most. We also make 5C collets with square or hex shaped bores for holding square stock, and we can add a groove or O-ring slot if your drawbar setup requires it. Custom engraving on the face (size marking, your logo, or a batch number) is free for orders over 5 sets. Tell us your lathe model—we will verify the taper fits your spindle before we cut.
Quality Control Checks for Long-Term Repeatability
We track every batch by heat number and machining date. If a collet fails in your shop, the batch number on the face lets us pull the exact material cert and process logs. We also test every 20th set for fatigue: clamping and releasing 10,000 cycles on a pneumatic drawbar, then re-checking runout. The runout must stay under 0.008mm after the test, or we reject the whole batch. This is what precision manufacturing has meant at BQUQ for the last 20 years—not just a one-time check, but proof that the part holds tolerance over its working life. For tighter requirements, read our CNC machining tolerances guide to see what we can guarantee.
What is the minimum order quantity?
No MOQ—we ship a single collet or a single 24-piece set to any address worldwide, though freight per piece is lower with more.
Can you make custom bore sizes or special shapes?
Yes, we machine square, hex, and custom step bores on any 5C collet, and we can adjust the size range in 0.5mm increments if you need finer steps.
How do you verify runout before shipping?
We measure every collet with a test bar and a 0.001mm dial indicator at three positions along the bore, and we include the readings in the shipment.
What is your lead time for a custom set?
Standard 24-piece sets ship in 7 days; custom bore shapes or special coatings take 12 days from drawing approval.
Send us your drawing or your size list today. We will reply with a firm quote and a delivery date within 12 hours (working days). Email sc@bquq.com or WhatsApp +86 13713157787. All our CNC machined 5C collet sets are precision manufacturing, made in China, with no MOQ.
