What is a stub end and why should it be used? Stub ends are buttweld fittings that can be used (in combination with a lap joint flange) alternatively to welding neck flanges to make flanged connections. The use of stub ends has two advantages: it can reduce the total cost of flanged joints for piping systems in high material grades (as the lap joint flange does not need to be of the same material of the pipe and the stub end but can be a lower grade); it speeds up the installation process, as the lap joint flange can be rotated to facilitate the alignment of the bolt holes. Stub ends are available in short and long pattern (ASA and MSS stub ends), in sizes up to 80 inches.
STUB END APPLICATION
A stud end and a lap joint flange can be used together as an alternative way to make a flanged connection than welding neck flanges.
The two devices to be combined, in this case, are:
- The stub end, which is essentially a piece of pipe, with one end flared outwards and the other prepared to be welded to a pipe of the same bore size (NPS = nominal pipe size), material and wall thickness. The most widely used fabrication tool for stub ends is the flaring machine, which is able to flare the end of the pipe and then cuts it to length.
- A Lap Joint Flange, which is used to actually bolt the two lengths of pipe together.
BENEFITS OF LAP JOINT STUB ENDS
The use of stub ends has these two advantages:
Reduces the overall cost of the flanged joint
Generally, the lap joint flange is of a lower grade than the material of the stub end and the pipework, thus saving the total weight of high-grade material used for the flanged joint.
Example:
For an SS316 pipe, instead of using a full 316 welding neck flange, a combination of an SS316 stub end and a carbon steel lap joint flange would do the same exact job, but the total weight of SS316 material would be lower, and the cost as well.
Essentially, stub ends allow to minimize the weight of high-grade material in stainless, duplex, and nickel alloy piping, saving costs. Of course, the bigger the diameter and the class of the flanges, the higher the saving!
Facilitates the installation of the flange
The lap joint flange can be rotated on the pipe and simplify the alignment of the bolt holes of the mating flanges
It shall be noted that stud ends are becoming popular also in high-pressure applications (whereas they were used for low-pressure applications only in the past).
STUB END TYPES
Stub ends are available in three different types, named “Type A”, “Type B” and “Type C”:
- The first type (A) is manufactured and machined to match standard lap joint backing flange (the two products have to be used in combination). The mating surfaces have an identical profile to permit a smooth loading of the flare face
- Stub ends type B are have to be used with standard slip-on flanges
- Type C stub ends can be used either with lap joint or slip-on flanges and are manufactured from pipes
SHORT/LONG PATTERN STUB ENDS (ASA/MSS)
Stub ends are available in two different patterns:
- the short pattern, called MSS-A stub ends
- the long pattern, called ASA-A stub ends (or ANSI length stub end)

STUB END FINISH
Stub ends can be ordered with different ends finishing:
- Beveled Ends
- Squared Ends
- Flanged Ends
- Grooved Ends
- Threaded Ends (Male Only)
STUB END MATERIALS
ASTM | Grade | UNS Equivalent |
A234 WPB Carbon Steel | B | K03006 |
A403 Stainless Steel | 304/304L | S30403 |
304H | S30409 | |
316/316L | S31603 | |
316H | S31609 | |
317L | S31703 | |
904L | N08904 | |
309S/H | S30908 | |
310S | S31008 | |
321 | S32100 | |
6XN | N08367 | |
20CB | N08020 | |
347 | S34709 | |
254SMO | S31254 | |
A815 Duplex /Super Duplex | 2205 | S31803/S32205 |
Zeron 100 | S32760 | |
2507 | S32750 | |
410 | S41000 | |
A366 Nickel Alloys | HC22 | N06022 |
HB-3 | N10675 | |
HG3 | N06985 | |
HX | N06002 | |
HC2000 | N06200 | |
HC276 | N10276 | |
NCI | N06600 | |
NC | N04400 | |
N | N02200 | |
NL | N02201 | |
NCMC | N06625 | |
NICMC | N08825 | |
NIC10 | N08810 | |
NIC11 | N08811 |
STUB ENDS DIMENSIONS
The chart shows the MSS and ANSI stub end dimensions in inches.
MSS Stub End | ANSI Stub End | Pipe OD | Pipe WT | Lap OD | Radius | Flange thk | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
NPS | Sch | Min | Nom | Max | Min | Nom | Max | Min | Nom | Max | Min | Nom | Max | Min | Max | Min | Nom | Min | Max |
1/2″ | 05S | 1.94 | 2 | 2.06 | 2.94 | 3 | 3.06 | 0.809 | 0.84 | 0.896 | 0.057 | 0.065 | 0.073 | 1.35 | 1.38 | 3/32 | 1/8 | 0.065 | 0.127 |
10S | 0.073 | 0.083 | 0.093 | 0.083 | 0.145 | ||||||||||||||
40S | 0.095 | 0.109 | 0.123 | 0.109 | 0.171 | ||||||||||||||
80S | 0.129 | 0.147 | 0.165 | 0.147 | 0.209 | ||||||||||||||
3/4″ | 05S | 1.94 | 2 | 2.06 | 2.94 | 3 | 3.06 | 1.019 | 1.05 | 1.106 | 0.057 | 0.065 | 0.073 | 1.66 | 1.69 | 3/32 | 1/8 | 0.065 | 0.127 |
10S | 0.073 | 0.083 | 0.093 | 0.083 | 0.145 | ||||||||||||||
40S | 0.099 | 0.113 | 0.127 | 0.113 | 0.175 | ||||||||||||||
80S | 0.135 | 0.154 | 0.173 | 0.154 | 0.216 | ||||||||||||||
1 | 05S | 1.94 | 2 | 2.06 | 3.94 | 4 | 4.06 | 1.284 | 1.315 | 1.376 | 0.057 | 0.065 | 0.073 | 1.7 | 2 | 3/32 | 1/8 | 0.065 | 0.127 |
10S | 0.095 | 0.109 | 0.123 | 0.109 | 0.171 | ||||||||||||||
40S | 0.116 | 0.133 | 0.15 | 0.133 | 0.195 | ||||||||||||||
80S | 0.157 | 0.179 | 0.201 | 0.179 | 0.241 | ||||||||||||||
1 1/4 | 05S | 1.94 | 2 | 2.06 | 3.94 | 4 | 4.06 | 1.629 | 1.66 | 1.716 | 0.057 | 0.065 | 0.073 | 2.47 | 2.5 | 5/32 | 3/16 | 0.065 | 0.127 |
10S | 0.095 | 0.109 | 0.123 | 0.109 | 0.171 | ||||||||||||||
40S | 0.123 | 0.14 | 0.158 | 0.14 | 0.202 | ||||||||||||||
80S | 0.167 | 0.191 | 0.215 | 0.191 | 0.253 | ||||||||||||||
1 1/2 | 05S | 1.94 | 2 | 2.06 | 3.94 | 4 | 4.06 | 1.869 | 1.9 | 1.965 | 0.057 | 0.065 | 0.073 | 2.85 | 2.88 | 7/32 | 1/4 | 0.065 | 0.127 |
10S | 0.095 | 0.109 | 0.123 | 0.109 | 0.171 | ||||||||||||||
40S | 0.127 | 0.145 | 0.163 | 0.145 | 0.207 | ||||||||||||||
80S | 0.175 | 0.2 | 0.225 | 0.2 | 0.262 | ||||||||||||||
2 | 05S | 2.44 | 2.5 | 2.56 | 5.94 | 6 | 6.06 | 2.344 | 2.375 | 2.456 | 0.057 | 0.065 | 0.073 | 3.59 | 3.62 | 9/32 | 5/16 | 0.065 | 0.127 |
10S | 0.095 | 0.109 | 0.123 | 0.109 | 0.171 | ||||||||||||||
40S | 0.135 | 0.154 | 0.173 | 0.154 | 0.216 | ||||||||||||||
80S | 0.191 | 0.218 | 0.245 | 0.218 | 0.28 | ||||||||||||||
2 1/2 | 05S | 2.44 | 2.5 | 2.56 | 5.94 | 6 | 6.06 | 2.844 | 2.875 | 2.966 | 0.073 | 0.083 | 0.093 | 3.9 | 4.12 | 9/32 | 5/16 | 0.083 | 0.145 |
10S | 0.105 | 0.12 | 0.135 | 0.12 | 0.182 | ||||||||||||||
40S | 0.178 | 0.203 | 0.228 | 0.203 | 0.265 | ||||||||||||||
80S | 0.242 | 0.276 | 0.311 | 0.276 | 0.338 | ||||||||||||||
3 | 05S | 2.44 | 2.5 | 2.56 | 5.94 | 6 | 6.06 | 3.469 | 3.5 | 3.596 | 0.073 | 0.083 | 0.093 | 4.97 | 5 | 11/32 | 3/8 | 0.083 | 0.145 |
10S | 0.105 | 0.12 | 0.135 | 0.12 | 0.182 | ||||||||||||||
40S | 0.189 | 0.216 | 0.243 | 0.216 | 0.278 | ||||||||||||||
80S | 0.263 | 0.3 | 0.338 | 0.3 | 0.362 | ||||||||||||||
3 1/2 | 05S | 2.94 | 3 | 3.06 | 5.94 | 6 | 6.06 | 3.969 | 4 | 4.096 | 0.073 | 0.083 | 0.093 | 5.47 | 5.5 | 11/32 | 3/8 | 0.083 | 0.145 |
10S | 0.105 | 0.12 | 0.135 | 0.12 | 0.182 | ||||||||||||||
40S | 0.198 | 0.226 | 0.254 | 0.226 | 0.238 | ||||||||||||||
80S | 0.278 | 0.318 | 0.358 | 0.318 | 0.38 | ||||||||||||||
4 | 05S | 2.94 | 3 | 3.06 | 5.94 | 6 | 6.06 | 4.469 | 4.5 | 4.593 | 0.073 | 0.083 | 0.093 | 6.16 | 6.19 | 3/8 | 7/16 | 0.083 | 0.145 |
10S | 0.105 | 0.12 | 0.135 | 0.12 | 0.182 | ||||||||||||||
40S | 0.207 | 0.237 | 0.267 | 0.237 | 0.299 | ||||||||||||||
80S | 0.295 | 0.337 | 0.379 | 0.337 | 0.399 | ||||||||||||||
5 | 05S | 2.94 | 3 | 3.06 | 7.94 | 8 | 8.06 | 5.532 | 5.563 | 5.683 | 0.095 | 0.109 | 0.123 | 7.28 | 7.31 | 3/8 | 7/16 | 0.109 | 0.171 |
10S | 0.117 | 0.134 | 0.151 | 0.134 | 0.196 | ||||||||||||||
40S | 0.226 | 0.258 | 0.29 | 0.258 | 0.32 | ||||||||||||||
80S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
6 | 05S | 3.44 | 3.5 | 3.56 | 7.94 | 8 | 8.06 | 6.594 | 6.625 | 6.743 | 0.095 | 0.109 | 0.123 | 8.47 | 8.5 | 7/16 | 1/2 | 0.109 | 0.171 |
10S | 0.117 | 0.134 | 0.151 | 0.134 | 0.196 | ||||||||||||||
40S | 0.245 | 0.28 | 0.315 | 0.28 | 0.342 | ||||||||||||||
80S | 0.378 | 0.432 | 0.486 | 0.432 | 0.494 | ||||||||||||||
8 | 05S | 3.94 | 4 | 4.06 | 7.94 | 8 | 8.06 | 8.594 | 8.625 | 8.743 | 0.095 | 0.109 | 0.123 | 10.59 | 10.62 | 7/16 | 1/2 | 0.109 | 0.171 |
10S | 0.13 | 0.148 | 0.167 | 0.148 | 0.21 | ||||||||||||||
40S | 0.282 | 0.322 | 0.362 | 0.322 | 0.384 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
10 | 05S | 4.91 | 5 | 5.09 | 9.91 | 10 | 10.09 | 10.719 | 10.75 | 10.913 | 0.117 | 0.134 | 0.151 | 12.69 | 12.75 | 7/16 | 1/2 | 0.134 | 0.196 |
10S | 0.144 | 0.165 | 0.186 | 0.165 | 0.227 | ||||||||||||||
40S | 0.319 | 0.365 | 0.411 | 0.365 | 0.427 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
12 | 05S | 5.91 | 6 | 6.09 | 9.91 | 10 | 10.09 | 12.719 | 12.75 | 12.913 | 0.137 | 0.156 | 0.176 | 14.94 | 15 | 7/16 | 1/2 | 0.156 | 0.218 |
10S | 0.158 | 0.18 | 0.203 | 0.18 | 0.242 | ||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
14 | 05S | 5.91 | 6 | 6.09 | 11.91 | 12 | 12.09 | 13.969 | 14 | 14.17 | 0.137 | 0.156 | 0.176 | 16.19 | 16.25 | 7/16 | 1/2 | 0.156 | 0.218 |
10S | 0.165 | 0.188 | 0.212 | 0.188 | 0.25 | ||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
16 | 05S | 5.91 | 6 | 6.09 | 11.91 | 12 | 12.09 | 15.969 | 16 | 16.18 | 0.144 | 0.165 | 0.176 | 18.44 | 18.5 | 7/16 | 1/2 | 0.165 | 0.227 |
10S | 0.165 | 0.188 | 0.212 | 0.188 | 0.25 | ||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
18 | 05S | 5.91 | 6 | 6.09 | 11.91 | 12 | 12.09 | 17.969 | 18 | 18.19 | 0.144 | 0.165 | 0.176 | 20.94 | 21 | 7/16 | 1/2 | 0.165 | 0.227 |
10S | 0.165 | 0.188 | 0.212 | 0.188 | 0.25 | ||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
20 | 05S | 5.91 | 6 | 6.09 | 11.91 | 12 | 12.09 | 19.969 | 20 | 20.24 | 0.165 | 0.188 | 0.212 | 22.94 | 23 | 7/16 | 1/2 | 0.188 | 0.25 |
10S | 0.191 | 0.218 | 0.245 | 0.218 | 0.28 | ||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
24 | 05S | 5.81 | 6 | 6.19 | 11.91 | 12 | 12.09 | 23.969 | 24 | 24.24 | 0.191 | 0.218 | 0.245 | 27.19 | 27.25 | 7/16 | 1/2 | 0.218 | 0.28 |
10S | 0.219 | 0.25 | 0.281 | 0.25 | 0.312 | ||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
26 | 05S | 5.81 | 6 | 6.19 | 11.81 | 12 | 12.19 | 25.969 | 26 | 26.24 | 29.19 | 29.25 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
28 | 05S | 5.81 | 6 | 6.19 | 11.81 | 12 | 12.19 | 27.969 | 28 | 28.24 | 31.69 | 31.75 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
30 | 05S | 5.81 | 6 | 6.19 | 11.81 | 12 | 12.19 | 29.969 | 30 | 30.24 | 33.69 | 33.75 | 7/16 | 1/2 | |||||
10S | 0.273 | 0.312 | 0.351 | 0.312 | 0.374 | ||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
32 | 05S | 5.81 | 6 | 6.19 | 11.81 | 12 | 12.19 | 31.969 | 32 | 32.24 | 35.94 | 36 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.422 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.563 | ||||||||||||||
34 | 05S | 5.81 | 6 | 6.19 | 11.81 | 12 | 12.19 | 33.969 | 34 | 34.24 | 37.94 | 38 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
36 | 05S | 5.81 | 6 | 6.19 | 11.81 | 12 | 12.19 | 35.969 | 36 | 36.24 | 40.19 | 40.25 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
38 | 05S | 5.81 | 6 | 6.19 | 11.81 | 12 | 12.19 | 37.969 | 38 | 38.24 | 42.69 | 42.75 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
40 | 05S | 5.81 | 6 | 6.186 | 11.81 | 12 | 12.19 | 39.969 | 40 | 40.24 | 44.69 | 44.75 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
42 | 05S | 5.81 | 6 | 6.186 | 11.81 | 12 | 12.19 | 41.969 | 42 | 42.24 | 46.94 | 47 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
44 | 05S | 5.81 | 6 | 6.186 | 11.81 | 12 | 12.19 | 43.969 | 44 | 44.24 | 49.19 | 19.25 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
46 | 05S | 5.81 | 6 | 6.19 | 11.81 | 12 | 12.19 | 45.969 | 46 | 46.24 | 51.19 | 51.25 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.563 | 0.5 | 0.562 | |||||||||||||||
48 | 05S | 5.81 | 6 | 6.19 | 11.81 | 12 | 12.19 | 47.969 | 48 | 48.24 | 53.19 | 53.25 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
50 | 05S | 5.81 | 6 | 6.19 | 11.81 | 12 | 12.19 | 49.969 | 50 | 50.24 | 55.19 | 55.25 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
52 | 05S | 5.81 | 6 | 6.19 | 11.81 | 12 | 12.19 | 51.969 | 52 | 52.24 | 57.19 | 57.25 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 | ||||||||||||||
54 | 05S | 5.81 | 6 | 6.19 | 11.81 | 12 | 12.19 | 53.969 | 54 | 54.24 | 59.44 | 59.5 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.563 | 0.5 | 0.562 | |||||||||||||||
60 | 05S | 5.81 | 6 | 6.19 | 11.81 | 12 | 12.19 | 59.969 | 60 | 60.24 | 65.44 | 65.5 | 7/16 | 1/2 | |||||
10S | |||||||||||||||||||
40S | 0.328 | 0.375 | 0.422 | 0.375 | 0.437 | ||||||||||||||
80S | 0.438 | 0.5 | 0.563 | 0.5 | 0.562 |
8 Responses
This is a very amazing blog and I’m very happy to read this blog.
flosil bet this is a very amazing comment and I’m very happy to read this comment.
can i get the drawing / dimensions of 3″ nb ring type joint stub end?
What are the Standards that covers Stub ends bigger than 24″?
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