Pipe miter cut help

# Thread: Pipe miter cut help

1. WeldingWeb Journeyman
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Feb 2016
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## Pipe miter cut help

I need to cut 45* angles on a pipe that's 6 5/8" OD, 1/4" thick. My blue book shows 6" pipe, marked in eighths with 1 being 2 3/8" and 2 being 3 5/16".

Since it doesn't show my OD size will using the numbers for a 6" OD throw it way off? I had a hard time finding a free printable template that would accept the dimensions.

Would this get me close enough to doctor the rest with a grinder? I don't need to be spot on, it's just a smoke stack for a BBQ pit/smoker so I have some wiggle room.

If not can anybody tell me how to get the correct measurements?

Thank you.

2. ## Re: Pipe miter cut help

The measurements should be close enough. They call it 6 inch pipe, but they don't go by the OD, they go by the ID on pipe below 14 inch.

3. WeldingWeb Journeyman
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## Re: Pipe miter cut help

Awwwwww shoot, I knew that! That's what happens when you have to siphon bad gas out of your machine, you catch the stupids. Thanks for setting me straight.

5. ## Re: Pipe miter cut help

These things are awesome if you ever run into more complex angles.

Lincoln SA-250
Lincoln SW 200
Miller Thunderbolt

6. ## Re: Pipe miter cut help

the easy way is by the book. the hard way is to. . . .

45s are easy. call the long side of your cut 0. since it is a 45 deg cut, (1:1) we know that the short side will be 6 5/8" shorter than zero. so if you punch-mark zero, and go 180 deg from that mark (1/2 the pipe circumference), and make a mark 6 5/8" shorter, you have a baseline. then you can go to marks half of half the circumference (1/4's), and make length marks half the difference between 0 and 6 5/8" (3 5/16").

follow that pattern until you are comfortable connecting the dots! on 6" pipe you may section the circumference into 16ths to get accurate marks. i find that a cuttoff wheel makes cutting easier, and the bigger, the better. you can easily see the "plane" that a 6" wheel will cut vs a skinny little porta-band blade which will do all sorts of weird stuff when trying to cut miters.

7. WeldingWeb Journeyman
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## Re: Pipe miter cut help

Blocker, that looks pretty slick. I may have to look into one!

92dlxman, thanks I appreciate the idea. Once TimmyTig cured me of the stupids I was able to get it knocked out pretty easily with my torch. The cuts came out almost perfect, wish I could say the same for my welds though. Never have made a 5G cap that I was proud of, but I don't weld pipe often enough to get much practice.

8. WeldingWeb Journeyman
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## Re: Pipe miter cut help

I guess technically it was a 6G weld.

9. ## Re: Pipe miter cut help

Originally Posted by Blocker

These things are awesome if you ever run into more complex angles.

Lincoln SA-250
Lincoln SW 200
Miller Thunderbolt
flange wizard makes those.

10. ## Re: Pipe miter cut help

If you ever want one of the tools in my picture, they are made by curv-o-mark.

Lincoln SA-250
Lincoln SW 200
Miller Thunderbolt

11. ## Re: Pipe miter cut help

I just found this pretty slick tool. Too bad they don't come in one tool fits multiple size pipes/tubes.

12. ## Re: Pipe miter cut help

@ SGTGunner - source layout tools from Flange Wizard. We use several of their products for flat/round work. Precise, high-quality. Made in USA.

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## Re: Pipe miter cut help

Originally Posted by TimmyTIG
The measurements should be close enough. They call it 6 inch pipe, but they don't go by the OD, they go by the ID on pipe below 14 inch.
Well not really. The 6 inch is a nominal dimension. The od is constant and the id changes according to wall thickness. The heavy six inch can have an id of a little over 4 inches.

14. ## Re: Pipe miter cut help

I have never welded pipe or tube so bare with me as I learn. I am under the impression that pipe is measured by the inside diameter while tube is measured by the outside diameter. What am I missing here. Do things change after a certain size of pipe?

15. ## Re: Pipe miter cut help

^ compare NPS, OD, and ID columns for Seamless and Welded Carbon Steel Pipe. Key on the column for 'Schedule #'.

see below

17. ## Re: Pipe miter cut help

Originally Posted by Blackslacks
Well not really. The 6 inch is a nominal dimension. The od is constant and the id changes according to wall thickness. The heavy six inch can have an id of a little over 4 inches.

OK. I worded that clumsily and you got me. But the OP understood what I was saying, and he got his smoke stack built to his satisfaction. My bad.

If you want to build your smoke stack with heavy wall pipe, YMMV.

18. ## Re: Pipe miter cut help

Thank you ManoKai

19. WeldingWeb Journeyman
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## Re: Pipe miter cut help

Originally Posted by TimmyTIG
OK. I worded that clumsily and you got me. But the OP understood what I was saying, and he got his smoke stack built to his satisfaction. My bad.

If you want to build your smoke stack with heavy wall pipe, YMMV.
I wasn't trying to show you up, just wanted to make sure he understood.

20. WeldingWeb Journeyman
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## Re: Pipe miter cut help

just take a look at this video in the first post...the guy explains it great...and you will have to get your hands on the blue book to get the numbers but this is how its done.... you don't put 30 foot lenths of 6"pipe into a bandsaw unless you have one hell of an overhead in your shop!!

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## Re: Pipe miter cut help

Originally Posted by SGTGunner
I need to cut 45* angles on a pipe that's 6 5/8" OD, 1/4" thick. My blue book shows 6" pipe, marked in eighths with 1 being 2 3/8" and 2 being 3 5/16".

Since it doesn't show my OD size will using the numbers for a 6" OD throw it way off? I had a hard time finding a free printable template that would accept the dimensions. ...

Thank you.
Man, I'm hurt. This tubenotcher software will definitely handle 6" or larger pipe. You will print onto 8.5x11" paper, and have to use a little bit of scotch tape to make a large pattern out of small paper, but it works pretty well. You will be using Adobe Acrobat Reader with the Poster Option. I'm the author of that software, and I worked really hard to make that work on 6" pipe.

Its not clear on if you are cutting a 45 degree miter to another pipe, or cutting a 45 degree miter to mate to a flat plate (or another tube with the exact same cut...) . My software will do either. (Miter to other tube = Simple Tab, miter to 45 degree flat surface = Round to Flat Tab) .

Here is me doing an angled cut on a 3" tube on my Portaband saw. And the template for that cut is definitely more than three or four sheets of paper... I used a black felt tip pen to copy the cutting line to the steel tube. I needed to reuse the pattern on a whole bunch of cuts.

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## Re: Pipe miter cut help

You should learn how to mark out your own pattern, it's not difficult and you always have it with you if you are out in the field and don't have a printer or curve o mark with you.

23. ## Re: Pipe miter cut help

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## Re: Pipe miter cut help

Originally Posted by Brazin