What This 36 Type Collet Actually Does on Your Auto Lathe This is a CNC machined Auto Lathe 36 Type Collet With Pin Slot, built for high-speed Swiss-type and sliding-headstock lath
BQUQ CNC Machined Auto Lathe 36 Type Collet With Pin Slot
What This 36 Type Collet Actually Does on Your Auto Lathe This is a CNC machined Auto Lathe 36 Type Collet With Pin Slot, built for high-speed Swiss-type and sliding-headstock lathes. It grips bar sto
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What This 36 Type Collet Actually Does on Your Auto Lathe
This is a CNC machined Auto Lathe 36 Type Collet With Pin Slot, built for high-speed Swiss-type and sliding-headstock lathes. It grips bar stock from Ø3 mm to Ø36 mm with a concentricity runout of ≤0.005 mm TIR. That means your finished part roundness stays inside 5 microns, cycle after cycle. We hold the slot width and pin bore to ±0.003 mm, so the collet locks into your spindle nose without shimming or hand fitting. Made in China by BQUQ, 20 years of precision manufacturing, and we ship standard sizes in 7 working days.
How the Pin Slot Geometry Prevents Collet Rotation Under Load
Most collet failures start with rotation. The pin slot on this 36 type is not a cosmetic groove—it is a hardened locating feature. We mill the slot to a width of 4.0 mm ±0.005 mm and depth of 2.5 mm, matching the drive pin in your spindle. When the collet closes, the pin engages the slot flanks, not the slot bottom. This distributes torque evenly and eliminates the "jump" you get with round collets. The slot edges are deburred to 0.05 mm radius, so the pin slides in clean without catching on burrs. If your machine uses a different pin size, tell us the drawing—we will cut the slot to your spec.
Materials and Heat Treatment We Use for 36 Type Collets
We do not use free-cutting mild steel. The body is 20CrMnTi alloy steel, carburized to a case depth of 0.6–0.8 mm. Core hardness is 35–40 HRC for toughness; surface hardness is 58–62 HRC for wear resistance. The bore is ground after hardening, not before. That is the difference between a collet that lasts 6 months and one that lasts 2 weeks. We also offer a full-hard version in 9Cr18MoV stainless for corrosive coolant environments—same geometry, same tolerance. For spring-loaded variants, we use 65Mn spring steel, tempered to 44–48 HRC, with the slot cut after tempering to avoid distortion.
Grinding Sequence That Keeps Runout Below 5 Microns
Runout is not a single operation—it is a sequence. We rough turn the OD, then heat treat, then grind the bore to Ø36.000 mm +0.005/-0.000. Next, we press the collet onto a precision mandrel (the mandrel itself is ground to 0.002 mm TIR) and grind the OD taper to 1°30' ±2'. The pin slot is cut last, using a wire EDM, so the slot does not distort the bore. Every collet is checked on a Marposs gauge station: bore diameter, taper angle, slot width, and TIR. We keep a Cpk of ≥1.33 on all critical dimensions. If you need a copy of the inspection report, it ships with the box—no extra charge.
Inspection Before Every Shipment: What We Measure
Every single collet gets a full dimensional check, not a batch sample. We measure: bore diameter at three depths, slot width and depth, pin slot position relative to the bore axis, taper angle on a sine plate, and TIR on a 0.0001 mm indicator. Surface finish is verified with a Mitutoyo SJ-210 profilometer—Ra 0.4 µm on the bore, Ra 0.8 µm on the taper. Hardness is tested on a Rockwell C scale at two points on the OD. If any reading is out of spec, the collet is scrapped, not reworked. We also do a 100% visual check for edge break and surface defects under 5x magnification.
Why the 36 Type Fits Most Swiss Lathes Without Modification
This collet follows the standard ER-36 and 36 type cross-reference dimensions. The taper angle is 1°30', the threaded pull-back section is M36 x 1.5, and the overall length is 60 mm. It fits machines from Citizen, Star, Tsugami, and most Chinese auto lathes that accept the 36 type. If your spindle uses a 35 mm or 38 mm pull-tube, the OD can be adjusted—just send your drawing. We keep 12 standard sizes in stock (Ø3, Ø4, Ø5, Ø6, Ø8, Ø10, Ø12, Ø14, Ø16, Ø20, Ø25, Ø32) for same-day dispatch. Non-standard bores (e.g., Ø7.5 mm) are machined in 3 days.
Lead Time, MOQ, and How We Keep Price Down
No MOQ. That is a standing policy for all BQUQ collets, not a promo. Standard sizes ship in 7 working days. Custom bore diameters with the same slot geometry ship in 10 working days. For a full custom collet (different material, different slot position, different taper), lead time is 15 working days after drawing approval. Price depends on material and quantity. For 1–10 pieces, unit price is around $18–$25. For 100+ pieces, price drops to $9–$12. We use CNC turning and grinding in-house, so there is no outsourcing markup. Freight is DHL or FedEx, door-to-door, 3–5 days to the US or EU.
Specification
Value
Product Name
CNC Machined Auto Lathe 36 Type Collet With Pin Slot
Material
20CrMnTi (carburized) or 9Cr18MoV stainless
Hardness (Surface)
58–62 HRC (carburized case)
Hardness (Core)
35–40 HRC
Bore Diameter Range
Ø3 mm to Ø36 mm (custom bore available)
Bore Tolerance
+0.005 mm / -0.000 mm
Slot Width Tolerance
±0.003 mm
Concentricity (TIR)
≤0.005 mm
Surface Finish (Bore)
Ra 0.4 µm
Surface Finish (Taper)
Ra 0.8 µm
Taper Angle
1°30' ±2'
Overall Length
60 mm
Lead Time (Standard)
7 working days
MOQ
No MOQ (1 piece accepted)
FAQ: Custom Slot Positions and Material Options
Can you make the pin slot on the opposite side?
Yes, we can rotate the slot position to any angle (0°–360°) relative to the collet's orientation mark—just specify the degree on your drawing.
Do you offer a coated version for dry machining?
Yes, we offer TiN or TiAlN coating on the bore and taper, which raises surface hardness to 85 HRC equivalent and reduces friction—ideal for aluminum or brass without coolant.
How do you guarantee no burrs on the slot edges?
We wire EDM the slot, then use a ceramic brush to break edges to a 0.05 mm radius, and inspect under 5x magnification—burrs are rejected, not shipped.
Can I get a sample before placing a bulk order?
Yes, we ship single samples via DHL Express within 24 hours of confirmation—sample price is the same as unit price for 10 pieces, but the cost is refunded on your first bulk order.
Get a Firm Quote in 12 Hours—Send Your Drawing
Send us your part number, drawing, or just a photo of your current collet. We will confirm the bore size, slot position, and taper within 4 hours, and a firm quote with freight within 12 hours. For engineering questions about collet gripping force or material selection, read our CNC cutting tool selection guide and CNC machining tolerances guide. Email your drawing to sc@bquq.com or WhatsApp +86 13713157787. We reply in English, Chinese, or Spanish—no MOQ, no minimum order value, just precision manufacturing from Dongguan.
