Brass Tube Fittings

Brass tube fittings are push-in assemblies that grip polyurethane or nylon tube with a collet and O-ring, making a sealed pneumatic connection by hand in seconds. Vikay supplies PU connector, elbow, tee, equal and bulkhead assemblies in brass, in tube sizes from 4 mm to 12 mm with BSP and NPT threaded ports.

Where a pneumatic circuit is rebuilt often, a push-in tube fitting saves more time than any other connection. Push the tube in against the collet and it locks and seals; press the collar and it releases, leaving the tube reusable.

Vikay's brass tube-fitting range covers PU connector assemblies (male thread to tube), equal connectors (tube to tube), PU elbow and equal elbow assemblies, PU tee and equal tee assemblies, female connectors and bulkhead assemblies. Bodies are turned from free-cutting brass rather than moulded in plastic, which is why they survive vibration, heat near compressors and workshop handling that breaks composite bodies. Threads are cut to ISO 228 (BSPP), ISO 7/1 (BSPT) or ASME B1.20.1 (NPT).

These assemblies are used on air-preparation units, cylinder and valve manifolds, instrument air runs, blow-off and clamping circuits, and on mining and construction equipment where the ambient is hostile. Working pressure is set by the tube, typically 10 to 16 bar for PU, so match tube wall to duty. Tell us the tube outside diameter, port thread and pattern and we will quote from stock sizes.

Frequently Asked Questions

What tube do push-in brass fittings accept?

Polyurethane and nylon tube in the catalogued outside diameters, commonly 4, 6, 8, 10 and 12 mm. The tube must be cut square with a tube cutter. A knife cut leaves an angled face that the O-ring cannot seal against, which is the most common cause of a hissing joint.

Why choose brass instead of a plastic push-in fitting?

Brass bodies tolerate heat, vibration, oil mist and mechanical knocks that crack acetal or polypropylene bodies. On compressor outlets, mobile plant and anywhere the line is stepped on or dragged, brass is the more durable choice for a small cost difference.

How do I release the tube from a push-in fitting?

With the line depressurised, press the release collar squarely towards the fitting body and pull the tube out at the same time. Pulling without pressing tightens the collet's grip. Always vent pressure first, because a tube released under pressure will whip.

What pressure will a PU push-in assembly hold?

The joint is normally limited by the tube, not the fitting: PU tube of standard wall is typically rated around 10 bar at 20 degrees C, falling as temperature rises, and nylon somewhat higher. Confirm the tube manufacturer's rating for your working temperature.

Are bulkhead versions available for panel mounting?

Yes. PU bulkhead assemblies are catalogued for passing an air line through a panel or enclosure wall with a locknut, giving a tube connection on both faces. State the panel thickness on your enquiry so the correct thread length is supplied.