There are two standards to which Texas Flange offers a variety of stub ends to accompany our flanges. The MSS standard is the regular length stub end and the most commonly used in the flange industry. The ASA type stub end is of a longer length and is less common than the MSS type, though it may be more suitable for your application.
MSS Type A stub ends are the industry norm and are utilized with standard flat face lap joint flanges. The lap thickness of the stub end typically meets the thickness of the schedule pipe it accompanies, and the exterior of the base has a curved machine radius for the lap joint flange to mate flush over the stub end. There are many instances in which lead time is critical and of more importance than adherence to existing ANSI / ASME flange specifications, and as such our customers will often choose to purchase a slip on flange and have the face machined to meet the radius requirement of the corresponding stub end piece. Furthermore, a standard lap joint flange will typically have a longer hub length in comparison to a slip on flange, but this is often considered unnecessary for many applications. Fabricators and field workers alike often choose to go this route in the event that a lap joint in a particular size or material grade is unavailable.
Texas Flange can provide custom stub ends to suit your application, provided we are given a technical drawing with dimensions of the necessary requirements. This is sometimes an option for when fabricators choose to utilize custom lap joint or mounting flanges to fit their application.