0.008mm Seat Repeatability Four-Jaw Grip Brass Welding Nozzle for Automated Torch Change

This four-jaw grip brass welding nozzle is the consumable that sits at the front of the torch and takes the most handling. The four jaws are not decoration: on automated torch change they are what the gripper holds, and they are also what keeps the nozzle concentric when the operator tightens it by hand. If the jaws are uneven, the gripper pulls the nozzle off axis on every change, and the gas shield drifts.

We turn the body, cut the four jaws, mill the hex flats and cut the threaded base in one clamping, so the jaws, the seat and the thread share a single centre line. Seat repeatability is held to 0.008 mm, which means a replacement nozzle seats at the same height and angle as the one it replaces. The body is machined from C36000, C26000, C46400 or lead-free brass, with polishing, nickel plating or clear lacquer as the finish.

1. Drawing review and DFM. We confirm jaw width, jaw depth, seat angle, thread callout, hex size and gripper interface, then return a marked drawing and quotation within one working day.
2. Material verification. Brass bar is checked against the mill certificate for grade and temper; lead-free grades are confirmed against the potable-water specification where required.
3. Cutting and facing. Bars are cut with facing allowance and both ends faced square, so the seat and thread start from true faces.
4. Turning the body and seat. The tapered body, seating face and thread relief are turned in one programme, with the seat finished to Ra 0.4 µm.
5. Four-jaw milling. The jaws are milled with a small end mill, indexed at 90 degrees from the same datum, so opposing jaws stay symmetric within 0.02 mm.
6. Hex and thread. Hex flats are milled to ±0.05 mm, and the external thread is cut to 6g on the same machine with the seat as reference.
7. Deburr, polish and plate. Jaw roots and thread ends are deburred, the part is polished, then nickel plated or lacquered with the thread and seat masked where the fit must not change.
8. Final inspection and packing. Seat height and concentricity checked 100% on a fixture, thread by go / no-go gauge, then bagging with a first article report.

An automated torch changer grips the nozzle on the jaws, not on the body. If one jaw is 0.03 mm wider or sits 0.02 mm higher, the gripper closes on an uneven surface and the nozzle tilts as it is pulled. The tilt is small, but the gas shield and the contact tip height both move with it, and the cell starts producing porosity on one side of the seam. We index all four jaws from one datum, check opposing pairs with a height gauge, and verify seat height on a fixture for every piece rather than sampling.

Every nozzle is built to your drawing: jaw count and width, jaw depth, seat angle, thread size and type, hex size, body taper, overall length, brass grade and finish. One piece is a normal order with no tooling charge and no setup fee, and the prototype runs on the same programme and inspection fixture as the batch. If a feature would raise cost without improving grip or repeatability, our engineer returns a DFM note with a practical alternative and waits for written approval before cutting metal.

• NDA before files. A mutual non-disclosure agreement is signed before drawings, samples or torch models are released, covering geometry, volume and end customer.
• No public reference. Confidential nozzles are never used as samples, catalogue items, website photos or trade show parts; photos need written release.
• Separated production. Sensitive jobs run in a designated cell with named operators, and programmes and fixtures are stored under a project code.
• Controlled data. Drawings stay on an access-controlled server, and plating partners receive the process specification only.

Dongguan Changxinda Precision Technology Co., Ltd has machined custom metal parts since 2008. The plant runs four-axis and five-axis machining centres, turn-mill combined lathes, CNC lathes and milling machines, with 90 to 102 employees and an ISO 9001:2015 quality system. More than 200 customers are served, 50 to 60 percent of output is exported, and annual sales are between USD 10 million and 20 million. Every custom project has a named engineer, every batch ships with a first article report, and every delivery date is confirmed before the order is accepted.

• Confirmed dates. Prototypes in 3 to 7 working days, batch orders in 10 to 18 working days after drawing approval.
• Repeat orders skip setup. Programmes, fixtures and gauge sets stay on file, so the second order starts in production.
• Reserved capacity. Blanket orders are booked into fixed monthly machine time, keeping the same part arriving in the same week.
• Early warning. If material, plating or gauging threatens the date, you are told before the date is missed, with a partial shipment option.
• Dispatch evidence. Production photos, inspection report and packing list before shipment, tracking number on the day of dispatch.

• ✅ Consumer Electronics: phone, tablet and laptop housings, heat sinks, camera brackets, VR/AR headset structural parts, smart wearable shells
• ✅ Automation & Industrial Equipment: automation fixtures, jigs, module frames, transmission sliders, motor mounts, sensor housings, conveyor line parts
• ✅ Semiconductor & Vacuum Equipment: vacuum chambers, vacuum fittings, precision equipment bases, thermal isolation and insulation parts, inspection fixtures
• ✅ Medical Devices: surgical instrument bases, diagnostic instrument housings, endoscope components, aesthetic device structural parts (medical-grade aluminum and stainless steel)
• ✅ Automotive: new energy motor housings, battery end plates, sensor brackets, lamp structural parts, tuning parts, hydraulic valve blocks
• ✅ Aerospace & UAV: aircraft structural parts, drone frames, landing gear parts, avionics instrument housings (lightweight precision parts)
• ✅ Optics & Photonics: optical lens barrels, lens mounts, light source heat sinks, camera module brackets, inspection optical benches
• ✅ Communications: 5G heat dissipation cavities, filter parts, signal adapter structural parts, telecom equipment housings
• ✅ Robotics: robot arm joint parts, robot bases, reducer housings, AGV structural parts
• ✅ Instrumentation: test equipment housings, precision gauge bases, flow meter parts, laboratory equipment accessories

Each nozzle is bagged with a desiccant sachet, separated by EPE foam so polished jaws and threads cannot knock against each other, and packed in a five-layer export carton marked with part number, quantity and batch code. Sea freight goes on a fumigation-free plywood pallet with strapping and stretch film; air freight uses a reinforced carton with edge protectors. Neutral packing is available for distributors selling under their own brand.