This is a CNC machined Auto Lathe 36 Type Collet with an external thread rear closeup design. It delivers 0.005 mm TIR (total indicated runout) and a surface finish of Ra 0.4 µm, hardened to 58–60 HRC
This is a CNC machined Auto Lathe 36 Type Collet with an external thread rear closeup design. It delivers 0.005 mm TIR (total indicated runout) and a surface finish of Ra 0.4 µm, hardened to 58–60 HRC for extended tool life. We ship standard sizes in 7 days, with no MOQ, from our 20-year precision manufacturing facility in Dongguan, China.
The rear external thread allows direct mounting onto the spindle nose without a drawbar adapter. This reduces the stack-up length by 12 mm compared to internal thread designs. Shorter tool overhang means less deflection under heavy cutting. For a 36 type collet, this translates to 18% higher gripping force at the same clamping torque. The rear closeup configuration also allows a larger through-hole bore—up to 28 mm diameter—for bar stock feeding.
We start with 20CrMnTi alloy steel, pre-hardened to 28 HRC for machining. After CNC turning and thread grinding, we carburize to a case depth of 0.8–1.0 mm. Final hardness is 58–60 HRC on the gripping surface, while the core stays at 35–40 HRC for toughness. This dual hardness prevents both wear and brittle fracture. Each collet is cryogenically treated at -120°C to stabilize the microstructure, ensuring dimensional stability over 10,000+ clamping cycles.
Our machining process uses a 5-axis CNC lathe with live tooling. Step one: rough turn the OD and bore with a 0.3 mm stock allowance. Step two: heat treatment as above. Step three: finish grind the external thread to ISO 6g tolerance. Step four: wire-cut the 12 longitudinal slots. Step five: hone the internal bore to a mirror finish. The final inspection measures runout at three points: front, middle, and rear. We reject any collet with runout above 0.005 mm at the front gripping zone.
We use a Zeiss CMM and a TIR gauge with a precision mandrel to verify each collet. The mandrel itself has 0.002 mm runout. We measure the collet's internal bore runout at 5 mm from the front face and at 20 mm depth. The maximum allowable deviation is 0.005 mm at the front and 0.008 mm at the rear. This is 40% tighter than the industry standard for 36 type collets. We also test the gripping force at 20 Nm clamping torque—the average is 8.5 kN, with a standard deviation of 0.2 kN.
Every single collet goes through a 9-point inspection before packing. We measure the external thread pitch diameter with a thread micrometer, the bore diameter with an air gauge, and the slot width with a vision system. We also perform a Rockwell hardness test on the gripping face and a surface roughness check with a profilometer. If any parameter is out of spec, the collet is scrapped—not reworked. Our rejection rate is 2.1% on incoming material, and 0.4% on finished goods, which we track monthly.
Each collet is individually wrapped in anti-rust paper and placed in a foam-lined plastic box. The box is marked with the part number, batch code, and date of manufacture. For OEM orders, we can laser-engrave your logo and part number on the front face. We also provide a material certificate and a dimensional inspection report with every order over 100 pieces. The batch code allows full traceability to the original steel lot and heat treatment furnace records.
Standard thread is M36 x 1.5. We can also machine M36 x 1.0, M36 x 2.0, or UNF 1-1/2-12. For special bore diameters, we can produce any size from 4 mm to 28 mm in 0.1 mm increments. We also offer a version with a center through hole for coolant delivery, and a version with a hardened and ground rear face for better seating. Custom lead time is 12–15 days for quantities up to 500 pieces.
| Parameter | Value |
| Type | 36 Type Collet (Auto Lathe Series) |
| Thread Specification | External M36 x 1.5 (ISO 6g) |
| Rear Closeup Design | Yes, external thread rear mounting |
| Material | 20CrMnTi alloy steel |
| Hardness (Gripping Surface) | 58–60 HRC |
| Core Hardness | 35–40 HRC |
| Runout (TIR at Front) | 0.005 mm |
| Surface Finish (Bore) | Ra 0.4 µm |
| Gripping Range | 4 mm – 28 mm bore diameter |
| Lead Time (Standard) | 7 working days |
| MOQ | No MOQ (1 piece accepted) |
We have no MOQ—you can order a single piece for prototype testing or a thousand for production; the unit price adjusts based on quantity.
Yes, we can machine any bore from 4 mm to 28 mm in 0.1 mm increments, and modify the external thread to M36 x 1.0, M36 x 2.0, or UNF 1-1/2-12 with a 12-day lead time.
We use SPC (statistical process control) on every batch, sampling 5 pieces every 2 hours for runout and hardness; the CMM inspection report is included with each shipment.
For standard 36 type collets in stock, we can ship within 48 hours via DHL Express; custom orders take 12–15 days depending on thread and bore modifications.
For selecting the right cutting tools to pair with this collet, see our CNC cutting tool selection guide. If you need to verify your drawing's dimensioning approach, review our CNC machining tolerances guide first.
This precision manufacturing component is made in China at our 20-year-old Dongguan factory. We specialize in CNC machining, stamping, springs, and heat sinks for global OEMs. The 36 type collet with external thread rear closeup is a stock item—we keep 500 pieces in inventory for immediate shipment. No MOQ applies to this product, so you can validate your design with a single unit before scaling up.
Send your drawing for a firm quote within 12 hours. Email us at sc@bquq.com or WhatsApp +86 13713157787. We will confirm the thread, bore size, and runout requirement on your drawing within one business day.
| 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 |
