What are some standard dimensions for pipe coupling?

Standard dimensions for class 3000 full-pipe coupling include 1 1/4 and 3/4 inch for 1/8-inch pipe, 1 7/8 and 1 1/8 for a 1/2-inch pipe, and 3 3/8 and 3 for 2-inch pipe. Other coupling classes have different standard dimensions.

Class 6000 full-pipe coupling generally has a larger second dimension than class 3000 full-pipe coupling. For instance, the dimensions of class 6000 full-pipe coupling for a 1/8-inch pipe are 7/8 inch to 1 1/4 inches. The same is true of the difference between class 3000 half-pipe coupling and size 6000 half-pipe coupling. For example, class 6000 half-pipe coupling comes in size 5/8 and 7/8 for a 1/8-inch pipe.