When going down a half pipe how fast are you going?

If you are threading one half inch diameter steel pipe and it is going between two female fittings how much pipe needs to be cut if your center to center distance between the fittings is nine inches?

• Answer:

  I'm confused by your use of the term, center to center. I'm guessing you mean from the face of the fitting where the pipe threads in. You can usually screw in about 1/2 inch of pipe into a female fitting, so you would need 10 inches to end up with 9 in between. You can screw this together without a union in between? You can only put pipe together in one direction unless you use a union.