Determining length of black pipe

Jeff_17

When I measure a section of Black pipe for steam or other purposes BETWEEN two fittings ....let's say two elbows....If the distance between the elbows is 9 inches...what should be the length of the black pipe nipple between them?

Uni R

Depends on diameter...

0.5" is 0.53"


0.75" is 0.55"


1" is 0.68"


1.25" is 0.71"


1.5" is 0.72"


2" is 0.76"


3" is 1.20"


4" is 1.30"

Tony Conner_2

Length Of Pipe

Remember that if you're running between things like a pair of 90*s, you'll need a union somewhere.

Consider finding a copy of Audel's "Mechanical Trades Pocket Manual". It has a load of really good information on a broad range of technical subjects, and among it is a table for the "Take Aways" for screwed fittings.

Jeff_17

Hold on....

This is simple.. I have 3/8 in pipe that I need to join. I understand that I need unions, etc...BUT I just need what EXTRA lenght I allow for the length of pipe that is actually screwed into the elbows, unions, etc....for example...if it is an 8 inch nipple..do I CUT/BUY 8.5 in nipple..or longer?

Uni R

3/8\"

Normal depth for tight joint is 0.41" at each end. You'll need a piece about 8.8" long.

Jeff_17

Now...

i understand!!! Thanks sooo much!

Tony Conner_2

The Total...

...make up for each 3/8" thread will be 7/16". So for two fittings, you'd need to add 7/8" to your length. If a union has to go in, then the take-away or take-off is 7/8". This means your end-to-end length of pipe is 8 - 7/8". Take away for a union, if required, and the total length is 8". You need two nipples totalling 8" long - one each side of the union. It just happens with this pipe size that the two values cancel each other out. A pair of 4", a 5" and a 3" - doesn't really matter. It won't necessarily work out this way with all pipe sizes or fittings, so don't assume. If you don't need a union in this piece of pipe, then it's 8 - 7/8" end to end.

To keep it straight, it's often better to work centre to centre or end to centre, then everything is a subtraction.

Jeff_17

That helps EVEN...

> i understand!!! Thanks sooo much!

Jeff_17

That helps EVEN...

MORE!!! I do need one union to join to lenghts. Forgt what size, but I can figure it out from what you have said!