Stub End Types and Specifications

Stub ends come in three main types: Type A, Type B, and Type C. Each has a different design and compatibility with lap joint and slip-on flanges.

For example, Type A works best with lap joint flanges, while Type B fits slip-on flanges. Type C is more versatile, working with both but with a slightly different design.

The right type depends on how the stub end will connect to the flange and whether the application requires easy bolt alignment, frequent disassembly, or cost savings.

Let’s take a closer look at how each type functions.

Why Use Stub Ends Instead of Welded Flanges?

Stub ends combined with lap joint flanges offer:

• Cost savings: The flange can be reused while only the stub end needs replacing.
• Easier maintenance: Allows quick disassembly without cutting or re-welding.
• Flexibility: The loose flange makes bolt hole alignment easier during installation.

Types of Stub Ends

Type A: Designed for Lap Joint Flanges

This stub end has a machined serrated face and a lap thickness that equals or exceeds the pipe wall thickness. The outer corner has a precise radius to fit a lap joint flange, making it easy to rotate and align bolt holes.

Type B: Compatible with Slip-On Flanges

Unlike Type A, this stub end is made to work with slip-on flanges used as lap joint flanges. It has a smaller outer radius, which allows slip-on flanges to sit properly. The machined face ensures a tight seal.

Type C: A Universal Fit

Type C stub ends are the shortest and most adaptable. They can be used with both lap joint and slip-on flanges. The inside edge is flared with a rounded transition, but it can be machined to a square edge if needed.

Lengths and Schedules

Stub ends come in MSS (short pattern) and ANSI (long pattern) lengths. The material thickness follows standard pipe schedules, including:

• Schedule 5s & 10s: Usually short length, ideal for low-pressure systems.
• Schedule 40s & 80s: Available in both short and long lengths for general industrial use.
• Custom lengths: Special orders are available for non-standard applications.

Choosing the Right Stub End

Need a stub end that fits? It comes down to flange type, material, and length. Pick the right match, and you get a strong, reliable connection.

Flange Compatibility

Type A works with lap joint flanges. Type B fits slip-on flanges used as lap joints. Type C does both but has a smooth lap instead of a machined face.

Material Selection

Stainless steel fights corrosion. Carbon steel keeps costs low. Duplex steel handles pressure and chemicals.

Length and Pressure Rating

MSS is short for low pressure. ANSI is long for high pressure. Match the length to your system, and you’re set.

Wall Thickness and Standards

Stub ends follow ASME B16.9, MSS-SP-43, and ANSI B16.28. Wall thickness matches pipe schedules, from Schedule 5S to Schedule 40.

Conclusion

Stub ends keep pipe connections simple and cost-effective. Picking the right type depends on your flange setup, material, and pressure needs.

At Longan Flange, we manufacture stub ends that meet ASME and MSS standards. Our stainless steel flanges are built for durability and precision. See our full range to find the best fit for your piping system.

Reference

Stub End Flanges: Design, Types, and Usage