Thread details matter
Thread requirements should be defined before quotation. Where possible, provide the thread standard, nominal size, pitch, fit class, thread length and gauge requirement together with the drawing. A small difference in thread specification can affect whether the part assembles correctly with the mating component.
- External and internal threads
- Threaded shafts, pins and connector rods
- Brass connectors, turned fittings and coupling bodies
- Custom rotational components with thread-machined features
- Replacement components where a catalogue fastener is not suitable
Design details for threaded parts
Thread relief, start position, shoulder location and chamfer details can affect assembly. If the component connects to a mating part, the drawing should show which thread surfaces and diameters are functional. For connectors and fittings, sealing faces or contact surfaces should also be identified.
Some threaded parts require a lead-in chamfer for assembly, while others need a thread to stop close to a shoulder. These details can change the tooling approach and inspection method. If the thread is used for sealing, clamping or alignment, the surrounding face and shoulder details may be as important as the thread itself.
Pins and connector components
Turned pins may include shoulders, grooves, heads, cross holes, threads, flats or retaining features. Connector components may include internal bores, external threads, wrench flats, sealing faces or hose-style connection details. These features should be shown clearly so the part can be reviewed as a functional component rather than a simple cylinder.
Materials and finishes
Threaded turned components may be made from steel, stainless steel, brass, aluminium or other specified metals depending on strength, corrosion exposure, conductivity, weight and appearance requirements. Brass is commonly considered for fittings and connector bodies. Stainless steel may be considered for corrosion resistance, while steel may suit strength or wear requirements.
Surface treatment should be discussed early. Plating, passivation, blackening, coating or deburring requirements can affect thread fit, appearance and packing. If a thread must be protected during shipping, packing requirements should be included in the quote request.
Inspection and functional fit
Thread gauges and dimensional inspection can be reviewed as part of the production plan. Fit requirements, mating components and intended use should be shared when they affect function. Inspection may include thread fit, major or minor diameter, length, shoulder position, sealing face quality, burr condition and appearance.
Common sourcing scenarios
Threaded CNC turned parts are often requested as replacement pins, custom fastener-style components, small connector bodies or fittings that are not available as standard catalogue parts. Clear thread specifications reduce the risk of mismatch after sampling. If an existing part is being replaced, photos of the mating assembly or a sample part can help clarify function before production drawings are finalised.