CNC Turning Multi-Segment Threaded Connector with 0.01mm Segment Coaxiality and 100% Go/No-Go Gauged Threads

Every thread on one axis, gauged 100%.

• Segment coaxiality0.01 mm — all threads and steps measured to one axis
• Thread class6g / 6H — go and no-go gauging on every threaded segment
• Order size1 piece — no tooling charge, prototypes in 3–7 working days
• Quality & materialsISO 9001:2015 · SS303 / 304 / 316L / 416 / 17-4PH · Passivated per ASTM A967 · Exporting since 2008

A multi-segment connector usually joins two different systems: a fine thread into an instrument body, a coarser thread into a hose or manifold, and a flange or shoulder that sets how deep each end engages. When the two threads are not coaxial, the part screws into the first port and then fights the second — the assembler blames the mating part, the seal leaks under pressure, and the thread flanks wear where the misalignment is taken up.

So the machining rule is simple: turn every diameter and cut every thread from one axis, in as few chuckings as the geometry allows, and gauge each thread separately. We turn on CNC lathes and turn-mill centres with a sub-spindle, so the second end is picked up on the same axis rather than re-chucked by hand. Coaxiality of all segments to the primary thread is measured on the CMM, and every threaded segment is run through go / no-go gauges before packing.

Thread class is the number that decides whether the part assembles, so it is gauged rather than sampled. Where a customer specifies a tighter fit or a controlled root radius, the drawing governs and the tool and insert are chosen to suit — we do not force every thread into a house tolerance.

• Material: SS303 (best machinability, fine threads), SS304, SS316/316L (corrosion), SS416 (high strength, magnetic), 17-4PH (after age hardening), brass C36000, aluminium 6061.
• Thread types: metric coarse and fine, UN/UNF/UNC, NPT, NPTF, BSPP, BSPT, M profile, trapezoidal, left-hand, multi-start.
• Features: 2 to 6 segments, flange or collar, hex or spanner flats, cross port, O-ring groove, knurl band, taper seat, internal thread, blind or through bore, laser marking.
• Finish: passivation per ASTM A967, electropolish, bead blast, black oxide, nickel plating, or as-machined.
• Size: OD 4 mm to 90 mm, length 10 mm to 300 mm, thread M4 to M42.
• Input: STEP, IGES, DXF, PDF drawing, or a sample fitting we measure and re-model.

Fitting drawings carry thread standards, sealing geometry and often a customer part number that identifies a whole assembly, which is why we treat the file as confidential from first contact. A mutual NDA is signed before any drawing is opened — ours in English or Chinese, or your own form — and a countersigned copy goes back before work starts. Only the project engineer, the lathe programmer and the cell supervisor have access, with the file in a restricted folder rather than the open shop network. No photographs of customer parts are taken for our catalogue or website, customer parts are never displayed or reused as samples, subcontracting requires your written approval, and at program close files and inspection data are deleted or returned with written confirmation.

Dongguan Changxinda Precision Technology Co., Ltd has been machining custom parts since 2008: 15+ years, 90 to 100 staff, 50–60% exported to North America and Europe, 200+ customers served, turnover in the RMB 10–20 million band. The floor holds CNC lathes, turn-mill combined centres with sub-spindle and live tooling, and 4-axis / 5-axis machining centres under an ISO 9001:2015 system, producing parts for medical, robotics, automotive, aerospace, automation, laser, LED, lithium battery and precision instrument programs. Turning, threading, milling, passivation coordination and gauging are all in our own plant in Dongguan.

Precision turned fittings from this plant ship into ten sectors. The list is what customers order, not a marketing wish-list.

All ten sectors run through the same plant and the same ISO 9001:2015 inspection discipline — only the material, finish and documentation package change.

• Prototype: 3–7 working days after drawing approval, including passivation and gauging.
• Small batch 10–100 pcs: 7–14 working days.
• Repeat orders: released from archived program, collets and thread tool list — threads come off the same tool, so the fit repeats.
• Capacity: 10,000 pieces per month across the plant.
• Visibility: a dated progress note with photos of your actual parts at turning, threading and gauging.
• Shipping: threads protected with caps or sleeves, individually bagged, foam-lined export carton, express or air and sea per your forwarder.
• Rush: weekly overtime slots held for line-down cases — give us the deadline and we confirm before the order.