1/4 inch x 3-1/2 inch Black Steel Nipple

1/4" x 3-1/2" Black Steel Pipe Nipple – Threaded Connector for Low-Pressure Piping Systems

The 1/4" x 3-1/2" Black Steel Nipple is a Schedule 40 threaded fitting used to connect pipe runs or extend existing piping in low- to moderate-pressure mechanical systems. This fitting features male National Pipe Taper (NPT) threads on both ends and is manufactured from carbon steel pipe conforming to ASTM A53 standards. It is commonly used in non-potable water, compressed air, and gas systems where corrosion from moisture is limited.

Technical Specifications

• Nominal Size: 1/4 inch NPT x 3-1/2 inch length
• Material: Carbon steel with black oxide coating
• Wall Type: Schedule 40
• Thread Standard: ANSI/ASME B1.20.1 (NPT, male x male)
• Manufacturing Standard: ASTM A733 for pipe nipples

Installation Guidelines

Before installation, verify thread compatibility and inspect for damage or debris. Use PTFE thread tape or compatible pipe dope on the male threads to ensure a leak-resistant connection. Tighten with standard pipe wrenches, applying even torque to avoid thread distortion. Pressure testing should follow local code and system specifications, especially in gas or pressurized systems.

Typical Applications

This black steel nipple is used in:

• Natural gas and propane piping systems (non-potable)
• Oil and fuel distribution lines
• Air compressor systems and pneumatic tools
• Closed-loop industrial fluid transfer applications

Its compact length makes it ideal for confined installations or joining close-coupled valves, fittings, or manifolds.

Material Notes

Black steel provides sufficient mechanical strength for general-purpose applications but offers minimal corrosion resistance. It is not approved for potable water distribution. In environments with high humidity or corrosive vapors, galvanized or stainless steel alternatives may be more appropriate.

The 1/4" x 3-1/2" Black Steel Pipe Nipple offers a durable, code-compliant connection solution for pressure-rated threaded systems. Designed for mechanical reliability and dimensional consistency, it supports efficient system layout and long-term performance in industrial and commercial installations.