take out forumla on 45

Date 07-13-2007 00:35

Take your pipe size and divide that number in half 3 times. Take the second and 4th number and add them together. That is your take off.

6
3
1 1/2
3/4 = 3 3/4

This works for everything except 2 inch, I think.....

By bearflow Date 07-13-2007 01:30

thanks for the tip so that means on a 8 inch pipe 45 takeout woud be 5 inch

By js55

Date 07-13-2007 13:20

ZCat comes in with an old pipe fighter method. I had forgotten that one.
Make sure you are working with standard radius tube turns.

By pipewelder_1999 (****)

Date 07-13-2007 14:28 Edited 07-13-2007 14:33

Here is another method that may be more of a pain but will come up with better accuracy. This is for a long radius ell. The advantage of knowing this is that it works for other degree turns.

Find the Tangent of 1/2 the angle of the ELL and multiply it times 1.5 times the Nominal Pipe Size.

It will come up with a slightly different answer.

TO=Tan(A/2)*NPS*1.5

TO=Takeout
A=Angle of Ell
NPS=Nominal Pipe Size

Have a nice day

Gerald

By Sourdough (****)

Date 07-16-2007 20:40

Truthfully, I never knew that formula........just knew the take outs.

Funny, you learn something new every day!!

By Kix

Date 07-17-2007 12:43

Those techniques are spot on for anything 4" and over, but as you drop in pipe size the accuracy starts to go down gradually with each drop in pipe size. It goes down in small increments eventually ending up off by 5/16" with a 1/2" piece of pipe.

.5/2=.25
.25/2=.125
.125/2=.0625
.25+.0625=.3125 or 5/16"

.414*.5*1.5=.3105 or 5/16" in my book ;-)

Actual take off for a 1/2" 45deg fitting is 5/8" so you'd be off 5/16" if you did the short cutt.

Happy pipe fittin!!

By pipewelder_1999 (****)

Date 07-18-2007 03:21

Using the dividing in half method gives a takeout that is .625*NPS. If the radius stays 1.5*NPS, the dividing in half method will have less overall error as the pipe size goes down.

Using the other formula the takeout is approx .621*NPS. The difference in the two will be .004 * NPS.

I THINK both methods work fine for ALL pipe sizes. But that is just theory as I havent worked on ALL pipe sizes:)

Every time I tried to explain to the fitters I had ,I ended up with gaps. When I didn't explain it, I ended up with gaps.

Thanks

Gerald

By Kix

Date 07-18-2007 13:12

A pipewelder i'm confused on how your getting .621 out of .414*.5*1.5. I'm taking half of 45deg witch is 22.5 then i take the TAN of 22.5 = .414 so I'm getting .414*.5*1.5=.3106
Then i do the divide in half method .5/2=.25 .25/2=.125 .125/2=.0625 Then i add the 2nd and 4th like so .25+.0625=.3125
How are you getting .625 and .621? Where am i screwing up cause you got what the actuall take off is.

By pipewelder_1999 (****)

Date 07-18-2007 14:42

I just made a spreadsheet using both methods and divided the calculated takeoff by the NPS. In all cases for all sizes the result was the same. The .625 is for the dividing in half method. The .621 is for the method using the Tangent. Both of these could be considered constants for figuring the takeout of a 45. Just like Takeout for a 90 = 1.5*NPS

TO=.621*NPS or
TO=.625*NPS

My math stopped in 9th grade with general math and the rest has been learned on my own so I am SUBJECT TO correction.

By scrappywelds (***)

Date 07-17-2007 23:57

5/8 the pipe's diameter will work too

By johnnyh (***)

Date 07-18-2007 15:39

[deleted]

By Kix

Date 07-18-2007 15:59

Ok multiply .5*.625 or 5/8" and what do ya get??? You get .3125 or 5/16" and that is the wrong take off for a 1/2" 45 and you got pipewelder up top coming up with the right answer .625 or 5/8" using spreadsheet. The multiply by 5/8" works spot on for a bunch of them, but your off by a 1/4" on 30" and 24" and maybe more. Anyone else have a fitter book to compare some take off's? Maybe my book has some screwy takeoffs. :-)

By pipewelder_1999 (****)

Date 07-18-2007 18:58

The .621 will work for all sizes of pipe that have a radius equal to 1.5 times the NPS. The .625 or dividing 3 times will have a slight error that will be more visible as the pipe gets larger.

The method using the tangent of 1/2 the angle works for all with better precision (.621). I couldn't find it in a pipefitting handbook. I think the ratio of the NPS to the radius of the turn remains constant for all sizes.

By pipewelder_1999 (****)

Date 07-19-2007 21:26

The formula ONLY applies to fittings with a radius equal to 1.5 times the nominal pipe size. 1/2" 3/4" and 1" ells may have a different radius.

By TRC

Date 09-11-2007 22:16 Edited 09-11-2007 22:38

Also this info can be found in the T.W. Franklin handbook under "Single Offset Bends" page 16 in the "Revised Edition". The take off would be letter "K". This illustration is for bending pipe but will also work when applied to weld fittings.*

*It will even work on 9" 90's---:)