Sleeve Parts & Couplers Suppliers

Zhejiangxinye Automobile Technology Co., Ltd. machines sleeve parts and couplers for automotive joints, brackets and adjustment mechanisms: internal-thread connecting sleeves, flanged step sleeves and suspension mounting sleeves produced as one machined part, with the thread, flange and step geometry held to drawing.

• Range position: one of three product groups inside CNC machined components, sleeves and pins, alongside pins and shafts and CNC precision machined components.
• Manufacturing base: Jiaxing, Zhejiang, China, with production from raw material through finishing and testing under one management system.
• Quality system: IATF 16949-2016, with documented work instructions for special and critical processes.
• Configuration: made to customer drawing — thread size and pitch, flange diameter and thickness, step diameter, overall length and surface finish.

The six production models below form our Custom Sleeve Parts & Couplers Suppliers, Exporter range. Each is a machined and threaded part; the differences lie in how the sleeve locates, clamps and seats against the mating bracket, bushing or bolt.

Sleeve Parts and Couplers We Supply

Choosing between flanged and unflanged versions is usually a question of insertion-depth control: a flange gives a positive stop against the bracket face, while a straight sleeve relies on bore depth and the mating bolt length. Stepped versions add a centring diameter for bushing bores; rounded ends protect adjacent parts during automated feeding and assembly.

Application Fit Across Vehicle and Industrial Assemblies

A sleeve carries out a specific task in a joint: it sets clamp length through a soft or thin section, protects a thread, spreads bolt load, or centres a bushing. Our parts are supplied into the following assembly positions.

• Suspension and chassis: flanged step sleeves in arm mounting, subframe brackets and bushing bores, where the step centres the part and the flange seats against the bracket.
• Seat structures: threaded spacers at adjuster pivots, rail fixings and frame joints, often combined with seat system nuts from our wider range.
• Body and trim: sleeves that pass through panels or plastic so clamp load is taken by the sleeve rather than the trim substrate.
• Exhaust and engine periphery: heat-resistant coating grades for sleeves positioned close to hot components.
• General industrial equipment: custom machinery where a catalogue spacer does not match the required thread, length or flange size.

Materials, Threads and Surface Finish

Sleeves are machined from carbon steel in the grade matched to the strength and forming requirement of the part. Drawing callouts on strength class, hardness and heat treatment are applied to the machined body and to the thread, and thread form is produced to the specified metric or inch standard.

• Threads: internal threads through or blind, with defined thread depth, chamfer and runout to the outside diameter.
• Geometry: straight cylindrical, flanged, stepped, rounded end and reinforced wall versions, machined as single parts.
• Heat treatment: applied where the sleeve carries structural load or the thread needs wear resistance.
• Coating: our in-house finishing line supports trivalent zinc plating with 480 h salt-spray performance and Zn-Ni alloy plating at 480–720 h; black finish is standard on the suspension mounting models.
• Temperature grades: heat-resistant finishes for 300 °C, 550 °C and 650–700 °C service where the part sits near exhaust or engine components.
• Handling: parts are degreased and threads protected before packing so the bore arrives clean and ready for assembly.

Tolerance, Repeatability and Inspection

Thread fit is the first acceptance point on a sleeve, followed by the relationship between the bore and the locating diameter. For different features and applications we apply tolerance bands from 0.06 mm to 0.30 mm, with the tighter end used for bore-to-step concentricity and the wider end for lengths that do not affect clamp load.

• Raw material analysis before release to production, covering grade and chemical composition.
• First-off approval and in-process checks at tapping, machining and finishing.
• Thread gauging with GO/NO-GO gauges, plus dimensional reports against the drawing.
• Hardness and mechanical performance testing of finished parts.
• Coating thickness and salt-spray verification on plated lots, to the agreed specification.

Assembly, Installation and Line Integration

Sleeves are usually pressed into a rubber bushing, inserted through a bracket bore or welded into a stamped component before the mating bolt is run in. We machine lead-in chamfers and rounded ends to suit the feeding method, and control outside diameter to the press-fit allowance specified for the receiving bore.

Coating choice is matched to the mating fastener so that the joint does not create a galvanic or galling problem during torque-up. Where the sleeve is robot-fed, we agree burr limits and end-face flatness so parts present correctly in the feeder track.

Information We Use to Configure Your Solution

A sleeve drawing gives us the starting point; the assembly conditions determine the final specification. We use the following inputs to prepare a proposal and to fix the process route.

Documentation, Packaging and Delivery Scope

Lots are supplied with the inspection records agreed at order review, together with material certification where specified. Packaging is defined around thread protection and flange edges: parts are packed in counted cartons, with bulk or layer packing selected according to how the sleeve is presented to the assembly line.

Production has run from Jiaxing, Zhejiang since 1995, and the plant operates a full-chain inspection system from raw material analysis to finished-product mechanical testing. That flow covers the sleeve parts and couplers range as well as the broader fastener, stamping and machined component programmes supplied to automotive customers.

Frequently Asked Questions

Can you machine sleeves to our drawing rather than a catalogue size?

Yes. The six models shown are production starting points; thread size, outside diameter, flange dimensions, step length, end form and coating are set from your drawing. We review thread depth against wall thickness and the press-fit allowance before confirming the route.

Which materials and finishes can you supply for sleeve parts and couplers?

Carbon steel is the standard base material, with the grade matched to the strength requirement. Finishing options include trivalent zinc plating at 480 h salt spray, Zn-Ni alloy plating at 480–720 h, black finish, and heat-resistant grades for 300 °C, 550 °C and 650–700 °C service.

How is thread and dimensional accuracy verified before shipment?

Threads are checked with GO/NO-GO gauges, and bore-to-step concentricity, flange thickness and overall length are measured against the drawing. Hardness, coating thickness and salt-spray performance are verified on the finished lot under our IATF 16949-2016 quality system.

Do you supply flanged, stepped and rounded-end variants?

All three are produced. Flanged and flanged step sleeves are used where insertion depth must be controlled, straight cylindrical sleeves where the bore sets position, and rounded-end sleeves where a sharp edge would damage rubber, trim or a mating surface.

What do you need from us to quote a sleeve or coupler?

A drawing or 3D model, material and strength class, thread callout, mating bolt specification, coating requirement, annual volume and release schedule, installation method and packaging preference. With those inputs we confirm the process route, inspection scope and lot documentation for the proposal.