gas pipe

Whenn measuring gas pipe for a new run, is the measurement taken from the inside of one corner to the inside of the next (ie: the pipe meets inside the elbow)? Is any extra length added to this measurement (ie: the pipe almost meets inside the elbow), other? What are the tricks of the trade to get the accurate measurement?
Thanks
jc
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I measure inside to inside of the fittings.
The threads do not loose but a fraction of the length. ~ 1/16 inch
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This is NOT correct. Half or three quarter inch pipes lose about one half inch on each end if they are tightened properly into the fittings. If you only enter 1/16", you will have severe leaking.
Just add an inch to the total length of the pipe and you can be pretty accurate. Pipes do not need to be as precise as most amateur plumbers think. There is generally a little "slack" in the measurements, achieved by adjusting a few other fittings in the run. And, if you are running a gas pipe for a kitchen range, who cares if it sticks out of the floor by exactly 6 inches. 5 " works just as well, as does 7'.
The best way I have found to measure pipes is to simply hold the fitting where I need it, measure to the next, and add an inch.
One other tip, if you dont have access to a pipe threader and have to rely on the standard sizes sold at hardware stores (usually by the foot or half foot), buy the longest piece, then use a coupler or union and buy a nipple to make up the difference.
For example. You need 28 1/2 inches. Buy a 24 inch, a coupler and a 5 inch nipple. (note, the coupler itself adds enough to subtract the threads that go into itself. But you still add the threads on the outer ends. If I am in one of the rare predicaments where I have to be very precise, I will also buy a 4 inch and a 6 inch nipple. That way I use the one that fits the best and later return the un-needed ones to the store. If you are still off by up to 1/2". Simply use the longer nipple and tighten the threads a little more.
Mark
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regards,
jc
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On Mon, 31 Oct 2005 22:03:54 GMT, "noonenparticular"

You're welcome !!!
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