formulas and charts

This might be a little better way to ask this question. I am about to take my NCCER test tomorow and need to find out the formulas for take offs on threaded pipe going into 46% and 90% tees and ells. Is it the same as Sch 40 pipe? I have been fitting for 5 years but I have never fit threaded pipe nor have I had any interest in fitting threaded pipe. Im not a bubble gum fitter by any means but Ive been kicked in the head WAY to much and getting mlown up in Iraq didnt help either! I just need a little technical direction.

www.en.wikipedia.org/wiki/National_pipe_thread it's all here or seek a copy of Machinist's handbook.

There are several books that have it. I have a "black book" that I use allot but I don't have it with me at the moment. I am a pipe fitter/welder but have in some instances fit threaded pipe. The general rule I use is the nominal pipe O.D. as the take off but this may not be the Official answer you seek. I will look through my books and see if I can find a table you can use. As far as threading goes I usually go one thread past the die edge and then tighten the fitting 2 turns past hand tight. Again this may be no where near officially correct but it has worked for me for the last 29 years. The blue book is in my opinion the best book for most of the welded pipe questions or problems one might come across.

pipewelder

pipewelder,

I am a machinist and is 1-1/2 turns past hand tight officially, but experience is proof of the pudding...

BamBam, I've been looking through what books I have here in my office and couldn't find a chart that has the specific dimensions of the cut backs you need. When I said I use the nominal pipe size as a cut back please remember to add the thread length that will be inserted into the fitting back to the the measurement. It gets confusing trying to explain the way I do it and my way could be completely wrong answer for your test. As B-wire stated that the machinists book says to tighten 1.5 turns where is I usually try to get 2 turns. I have a machinists handbook and they are very good sources of info. but not sure if it has the chart for fitting allowances. Through experience I have learned when possible to thread one end and make up the fitting before I measure so that I eliminate one variable before I layout the cut-line. I do this with welded pipe as well. I get better results measuring to center of a fitting on the end of a pipe and allow for only one fitting on the other end than I do trying to allow for both fittings. Sometimes you just can't do it this way but I find I have less mistakes when I can. You may find some good information on this website, I didn't have time to go through all of it but you might check it out. I'll keep looking when I have more time and good luck with your test!

http://www.systemsaver.com/morton-website/installation/plumbing-basics/copper-pipe.html

pipewelder

I appreciate the help everybody. I just got home from taking my NCCER and I aced it! I got a 93 on the test. I have never had any kind of tech. training in fitting just good ole fashion O.J.T. with a 64 year old grumpy asswhole fitter that seemed to make my life a living hell for a long time. UNtil I realized that half the bafoons that come out of school that has never even touched a wrench can even hold my wrap a round! Thanks again guys. By the way if youve heard that the Marathon job out here is a great opportunity to work here in Louisiana slap who ever told you that in the mouth!

Bam-Bam,

Nah! I hand them a pipe worth fitting (:

You're welcome...

Bam Bam, gratz on your test and good luck with your Pipe fitting!!! I to learned from a grumpy pipe fitter off the coast of Louisiana in the early 80's. I remember that no one wanted to work with Harry and being that I was the new guy from Alabama I got stuck being his helper. He made my life pure hell but he was a true combination hand and he taught me so much. After he figured out that I was serious about learning the trade he wasn't so bad to work with but let me tell you he would work you like a dog. It was probably the best thing I could have done for my career now that I look back. I now work as an project engineer in a paper mill and own and run a small pipe Fab. shop on the side. Although I am sure going to college and getting a mechanical engineering degree from the start would have been faster, the experience I got from 29 years of working the pipe trade is used nearly everyday and I wouldn't trade it for anything.

pipewelder

Shit thats how more than half of them got the job out there and the majority of the foremans!