What the 25-700 Series Covers and Why It Matters This is a complete collection of auto lathe collets from size 25 to 700, covering every standard spindle bore you will encounter on Swiss-type and CN
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What the 25-700 Series Covers and Why It Matters This is a complete collection of auto lathe collets from size 25 to 700, covering every standard spindle bore you will encounter on Swiss-type and CN
This is a complete collection of auto lathe collets from size 25 to 700, covering every standard spindle bore you will encounter on Swiss-type and CNC auto lathes. We machine these from hardened alloy steel, ground to a tolerance of ±0.005mm on the gripping diameter and a maximum runout of 0.005mm TIR. That means your bar stock sits dead center on the first pass—no rework, no scrap, no chatter marks. Our standard lead time for any size in this series is 10 working days, and we keep blanks in stock for the 25, 42, 65, and 100 sizes.
The series is built for continuous production. Hardness is held between HRC 58 and 62 on the gripping surface, and we nitride the bore to reduce wear when you run abrasive materials like 303 stainless or 17-4PH. You get consistent clamping force across the full range, which translates directly into longer tool life and better surface finish on your turned parts. For a precision manufacturing operation, that is not a luxury—it is the difference between holding ±0.01mm and chasing the tolerance all shift.
Runout kills precision. We attack it at the grinding stage, not the assembly stage. Every collet in this Cnc Machined Auto Lathe Full Series 25 To 700 Collet Collection is ground in a single setup, using a fixed centerless grinder with a diamond dresser that is re-trued every 50 pieces. The result: the gripping diameter and the taper seat are concentric to within 0.003mm before we even measure the final part.
The slots are cut with wire EDM after heat treatment, not before. That prevents distortion during hardening. We cut 6 slots for sizes 25-200 and 8 slots for sizes 300-700, which gives you uniform radial collapse without stress points. When you close the collet on bar stock, the force distributes evenly around the circumference, so you do not get the "three-lobe" effect that causes out-of-round parts. We verify this on a Talyrond machine for every batch, and the report goes in the box.
We use 8620 carburizing steel for the body and 6150 spring steel for the collet fingers. The body is carburized to a case depth of 0.8mm and hardened to HRC 60-62. The fingers are hardened and tempered to HRC 52-56, which gives them the springback you need for millions of cycles without cracking. This combination is not random—it is the same metallurgy used in high-end spindle tooling from Europe, but we make it in Dongguan at a lower cost.
For the gripping surface, we apply a titanium nitride coating on sizes above 300. That coating reduces friction coefficient to 0.4, which prevents galling when you clamp on pre-ground bar stock. If you run uncoated collets on a high-feed machine, you will see pickup marks on the stock within a week. With our TiN coating, those marks disappear. The coating thickness is 2-3 microns, and we test it with a Fischer scope on every 10th piece.
We do not ship a single collet without a full dimensional report. Each collet is measured for bore diameter, taper angle, runout, and hardness. The taper angle is checked with a sine bar and gauge blocks, not a protractor. The runout is measured on a precision spindle with a 0.001mm indicator, and we record the maximum TIR on the report. Hardness is tested with a Rockwell tester on the body and the finger tip separately.
The report includes the batch number, the machine operator, and the inspector's signature. You can trace any collet back to the heat treat furnace and the grinding wheel. We also do a 100% visual inspection under a 5x magnifier for edge chips, burrs, or grinding burn. If we see a burn mark, the collet goes to scrap—no rework. That is the standard for this Cnc Machined Auto Lathe Full Series 25 To 700 Collet Collection, and it is why our customers in automotive and medical device manufacturing reorder without sending a new drawing.
If you are not sure which size fits your spindle, send us the spindle nose taper angle and the max bar diameter. We will cross-reference it against our series chart and tell you the exact part number within one hour. The 25 series fits 1/8" to 1" bar, the 42 series fits 1/4" to 1-5/8", and the 700 series fits up to 2-3/4". We also make metric equivalents for each size, so you do not need to convert anything.
For custom bore diameters, we machine collets to your exact bar size, not just the standard increments. If you run 12.7mm stock but the standard collet is 12.5mm, we will open it up to 12.7mm with a tolerance of +0.005/-0.000. The lead time for a custom bore is still 10 working days, and the price only goes up 15% over the standard size. This is part of our precision manufacturing service—we do not force you to buy a stock size that does not fit your process.
Every collet is individually wrapped in VCI paper to prevent corrosion during ocean freight. The paper is oiled, but it will not leave residue on the steel. We pack 10 pieces per box for sizes 25-100, and 5 pieces per box for sizes 300-700. The outer carton is double-walled with foam inserts, so the collets do not knock against each other in transit. We have shipped over 12,000 collets in the last five years without a single damage claim.
Documentation includes the material certificate, the dimensional report, and the heat treat certificate. If you need a PPAP level 3 submission, we can generate that as well—it takes an extra 2 days and costs $50 per part number. For customers in Europe or North America, we can provide the EU RoHS declaration and the REACH compliance statement. We are not a trading company; we are the factory, so all documents come from our own quality system.
Price depends on size and quantity, but here is a ballpark for the standard series: size 25 costs $8.50 per piece at 100 pieces, size 42 costs $12.80, size 100 costs $24.50, and size 700 costs $68.00. These prices include the TiN coating and the full inspection report. If you order the full series (one of each size from 25 to 700), we give you a 20% discount and ship everything in one box with a wooden crate for protection.
We keep the cost low because we control the entire process in-house—heat treatment, grinding, EDM, and coating. We do not outsource any step, so there is no middleman margin. This is a real advantage of made in China manufacturing when you work directly with the factory. No MOQ means you can order 5 pieces for a trial run or 500 pieces for a production line. Our minimum order quantity is zero.
You should use these collets when you need fast changeover and repeatability on standard bar sizes. A hydraulic chuck gives you better damping but takes 20 minutes to swap out. Our collets swap in 2 minutes with a set screw or a quick-change nut. For a job shop that runs 10 different bar sizes in a day, that saved time is worth more than the slight damping advantage of a hydraulic system.
If you are running long, thin parts below 3mm diameter, a hydraulic chuck is better because it supports the bar more evenly. But for anything from 6mm to 70mm, our collets are the right choice. We also sell a companion set of collet chucks that match the taper, so you do not need to mix brands. If you are unsure about your application, send us a drawing of the part and the spindle, and we will recommend the correct setup. Our engineers answer within 12 hours.
No MOQ—you can order a single collet for testing, and we ship it the same week.
Yes, we machine custom bores to ±0.005mm on any size from 25 to 700, with a 15% price adjustment and the same 10-day lead time.
Every collet is 100% inspected with a Talyrond for runout and a Rockwell tester for hardness, and the report is included in your shipment.
Standard sizes ship in 10 working days, custom bores in 12 days, and full series crates in 15 days.
Stop guessing whether your collets are causing runout. Send us your spindle taper, bar size, and target tolerance, and we will confirm the exact part number and price within 12 hours. For a complete Cnc Machined Auto Lathe Full Series 25 To 700 Collet Collection, we will send a full quotation with a quantity discount table. We are a 20-year precision manufacturing factory in Dongguan, China, and we stand behind every part we ship.
Email your drawing to sc@bquq.com or add us on WhatsApp at +86 13713157787. We reply within 12 hours on business days, and we can arrange a video call to show you the inspection process in real time. If you need engineering advice before you order, check our CNC cutting tool selection guide or our CNC machining tolerances guide to match the right collet to your process. Send your drawing, get a firm quote, and start holding tighter tolerances next week.
We do not charge for the quote, and there is no obligation to order. You will get a PDF with the part number, price, lead time, and a preliminary inspection plan. That is the BQUQ way—clear numbers, no fluff, and parts that work on the first setup.
| Specification | Value |
| Series Size Range | 25 to 700 (metric and inch) |
| Body Material | 8620 carburizing steel |
| Finger Material | 6150 spring steel |
| Body Hardness | HRC 60-62 |
| Finger Hardness | HRC 52-56 |
| Gripping Diameter Tolerance | ±0.005mm |
| Maximum Runout (TIR) | 0.005mm |
| Surface Finish (Gripping Area) | Ra 0.4 µm |
| Coating (Size 300+) | Titanium Nitride, 2-3 µm |
| Lead Time (Standard) | 10 working days |
| Lead Time (Custom Bore) | 12 working days |
| MOQ | None—order 1 piece or 1000 |
| 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 |
