Best way to cut pipe at an angle?

[bdog]

I have 2-7/8” oilfield pipe set vertically in the ground for a shed. It is already concreted in the ground. I need to cut the tops off at desired height with a 2/12 (9.5 degree) angle so I can weld the I beam for the rafter resting on top of the pipes.

I have one of those gadgets that slips over the pipe to mark a saddle, straight cut, or 45 degree cut but how do I go about making a 9.5 degree cut on the pipe?

 

[monkeyduster]

Here is a web site that has a large number of calculators and printable patterns that might help.

www.blocklayer.com
Go to "Printable Templates" then "Pipe Notching Templates"

 

[bcp]

Maybe this will work.

On a scrap pipe, cut a 9.5 degree angle on a bandsaw. Then wrap it with light cardboard/stiff paper and trace the end. Cut off the part not wrapped around the pipe. Mark the high and low spots. Use this pattern to mark your standing pipes.

Bruce

 

[spitter]

Pipe fitter's handbook has all the proper formulas to layout angles on pipe. And a good wraparound. There are some good videos on UT they could explain it a whole hell of a lot better than I could.

 

[square1]

What tool (s) do you have to make the cut? Porta-band?
Build a jig that clamps / bolts to the pipe or to the porta-band to use as a guide
I have a 45⁰ & 22 1/2⁰ jig built so I don't have to mess with measuring / marking, etc...
Unfortunately they're in my storage unit 100+ miles away or I'd snap a pic & post it for you

 

[workinonit]

Porta-band and/or a Metabo. I'm making the assuption you already know how to calculate the angle and mark it.

 

[LD1]

The angle cut from high side to low side is a little less than 1/2".

Not knowing the tools you have at your disposal or what the method of choice for welding is....I'd probably just eyeball it close with a sawzall....fine tune with a grinder to desired angle. Its welding, not finish carpentry. So the joint dont have to be perfect for a good weld to follow

 

[Egon]

Just a piece of paper and mark out the angle using Tan tables. Then wrap it around the pipe for marking.

 

[bdog]

Thanks for the replies. I guess my issue is making the mark more than anything. I plan on making the cut with a torch. I can calculate vertically where the marks need to be. If say for example I was working with square tubing and not pipe I could make my marks and use a square to transfer them around to all sides of the square tubing. I am not sure how to do this with pipe.

As LD1 mentioned the difference is heights across the pipe is only roughly 1/2” but still if cut incorrectly that is a rather large gap to fill when welding in the overhead position. I also need to be able to balance a large heavy I beam on top of these cut posts so if the cut is wrong it is going to be very unstable while I am trying to weld it up there.

I am not sure what the “tan tables” you are referring to are Egon?

Monkey duster the block layer site is very cool and has a lot of information but the pipe notching templates I saw were all for pitting pipe to pipe. I need a simple angle cut to fit a pipe to a straight surface.

Bcp I like your idea and think something along those lines would work. This seems similar to what square1 suggested except manually marking it instead of building a jig.

 

[LD1]

2-7/8 od pipe has a circumference of 9"

Draw a triangle on a piece of paper ....9" base with 1/2" height.

Cut it out, wrap it around the pipe. It will get you close enough for torch work.

Or find something round and easy to cut an angle on with a bandsaw or meiter saw. Ironically.....just finished some leftover pizza for lunch and the grated parmesan cheese container is round, plastic, and right at 3" diameter. Would make a PERFECT template. Cut on angle....slip down over pipe and mark.

 

[Xfaxman]

--------------------
I have one of those gadgets that slips over the pipe to mark a saddle, straight cut, or 45 degree cut but how do I go about making a 9.5 degree cut on the pipe?

Get another straight cut gadget and cut it on a bandsaw to 9.5 degrees.

 

[tomplum]

Myself, I do better work with a jig made up to guide the cut rather than relying on following a mark. Find or make a piece of metal pipe -like 3" with the appropriate fit and a place to fit a line to locate it so they are all even.

 

[sandman2234]

Place a 2x4 or something at the height of the other end of the steel I-beam. Pull a string at the appropriate angle from the top of the 2x4 and to the pipe (or to another 2x4 further away). Once you have the string in place, you can cut it anyway you want, using the string as a guide. Remove the string during cutting and place it back to check your angle.
David from jax

 

[bdog]

Thanks guys. You got the gears turning and I can figure this out now.

 

[etpm]

Last summer I had 4 posts about 9 inches diameter that needed angled cuts made on the tops for a beam. The guy set wood at the right angle and height. Then used a laser level to show where to mark the posts. He used a sharpie. Then a chainsaw. it worked very well.
Eric

 

[gsganzer]

I wish I had the time to sketch it or a photo to show you another way I've seen it done. I've seen them notch the vertical pipe by cutting halfway through the diameter and then removing the notch material by cutting straight vertical with a cut-off wheel, so your truss will rest on the shelf of the remaining diameter. This lets you still slightly adjust the angle of the truss and do a vertical, rather than overhead weld.

I hope that makes sense, I'm in the middle of cooking dinner.

 

[lostcause]

This is how we did it back when I was starting out...

I first did it with pencil and paper, then eventually a computer, and finally a piece of 3d modeling software that would generate any pipe template configuration you could imagine. if you have any rudimentary drafting ability, or even want to learn for that matter, you can do this with a straight edge, scale (ruler), compass, and calculator. A t-square and adjustable triangle would really make it easy.

or, if you can use any CAD software, (you can download lots of free stuff) you can do it and print out the results to scale.

Basically, you draw a circle of the diameter of your pipe divided into 15 degree wedges, and an elevation view with the correct cut angle, you can project those across a set of equally spaced segments that match the diameter of the pipe. cut on the wavy line, and you're ready to mark the pipe.

A little google can probably find an online tutorial.

 

[lostcause]

I can send you a PDF file of a template if you want, and if you can print a PDF. I can't guarantee it will print to scale, not knowing what you use for software to print PDF files, but if it measures just over 9" long, then it should be to scale. I wold think Acrobat reader would be the best to print from.

 

[rScotty]

I'd find a chunk of pipe that is a slip fit over your uprights, then on my bandsaw I'c cut some 4" to 6" long" slip collars. Slide the collars on and you will find that the fit to the I beam will be perfect. You can adjust collar height to get the roof perfectly level and square..... and then tack the bottoms of the collars in place on the upright pipe.
rScotty

 

[Egon]

Tan table. Readily available on the internet.

tangent(9°) = 0.15838	tangent(25°) = 0.46631	tangent(41°) = 0.86929
tangent(10°) = 0.17633

draw a straight line one inch long. Add A vertical line .15838 inches high. Connect the start of line to the top of vertical line and you will have a 9 degree angle. Lay it out larger on a piece of wide tape and wrap on the pipe to be cut.

For 9.5 degrees extrapolate between 9 and ten degrees.