Cutting angles in 4+" pipe. Ideas?

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I've got a side business. I'll fab up almost anything you can think of. Well I recently got an order for a ranch hand rear bumper. I need to cut an angle in the pipe for the center to weld the plate in for the receiver to go. I got a couple orders for them so what's an easy way to get a perfect angle cut in it. I was thinking( say the angle I need is 45deg.) I can get a piece of 6x6 angle and cut the 45deg. angle in one side of it so I can just set it on the pipe and mark the angle that way. Y'all got any ideas?
Reply:I'm not visuallzing what exactly you are building, not that it matters much. My horizontal bandsaw would do a 45 deg angle on 6" pipe if needed, possibly 8". Set the angle, slap in the pipe and off it goes. I'm not sure if a 14" carbide metal cutting saw would do 4" on a 45 or not. They would be the "easy" way to go.You might also build a wrap from some acetate or flexable plastic and then cut it to match the cut pipe. Wrap it around the next piece and trace the line. I've seen rigid slip overs done from the next sized pipe as well. Someone here posted up a nice set used to do  1/2 angles for 45's and 22.5's for irrigation work last year IIRC..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Lay it out with a rap-a-round. Mark top of pipe (lengthwise line), mark bottom of pipe and both sides (lengthwise lines), mark the center of bend (around circumference of pipe), multiply pipe od by 1.414 then divide that by 2, make a mark to left of center of bed top of pipe with that #, make a mark to the right center of bend bottom of pipe-same number again, wrap top half and mark cut line, mark bottom half cut line. It sounds like a lot, but it will only take a few minutes. I tried to find you a video but no luck
Reply:You can buy a good pipe fitters book, and wrap around cheaper. Or buy one of these.http://www.pipemastertools.com/viewall.htmlYou may be able to print this out on legal paper, never tried it. http://metalgeek.com/static/cope.pcgiDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:As already suggested you can use a wrap around. You can also use a contour marker which is kind of expensive but if you are going to do much angle cutting of pipe is a VERY handy gadget to have. The cheap and easy way is to buy a set of templates at your LWS. The contour marker allows you to mark any degree cut you choose while the templates usually have 22.5 and 45 degree cuts.
Reply:Originally Posted by CEPYou can buy a good pipe fitters book, and wrap around cheaper. Or buy one of these.http://www.pipemastertools.com/viewall.htmlYou may be able to print this out on legal paper, never tried it. http://metalgeek.com/static/cope.pcgi
Reply:On 4" pipe a 1 1/2" or 1 1/4" angle iron works good as a straight edge.  You need a top line.  You mark the top on one end of the pipe and using the angle straight edge draw the top line onto the other end.  A long enough piece of angle to reach the other end works best.Once the top line is established you measure and mark the overall length you want.  Do this on the top line.  For what you describe the top is the "short side" of your cut.Now you need 3 more lines to mark.  The Bottom and each side lines.  These are easy to mark with a normal 2' framing square.  Lay the framing square on the pipe and place your top line on 1/2 the outside diameter of the pipe.  In your case your 4" pipe is probably 4 1/2" OD, so you put the 2 1/4" on the square on the top line then mark the other 2 1/4" mark on that side.  Roll the square and do the same again and get the bottom mark going from your new side mark.  Go the other way to mark the other side line, then double check it to your bottom mark.  It should be right.Now using your angle iron straight edge draw some lines for those 3 marks. Now you need a straight wrap-a-round line around the pipe at your overall length mark.  Next you need to measure 1 pipe diameter longer and put another wrap-a-around mark around the pipe.  Now put one 1/2 way between those two marks, ie: 1/2 diameter of the pipe.  Now you have 3 wrap-a-round lines around the pipe.Using your wrap-a-round line-up the two intersections of the side marks and the middle (1/2 diameter center) wrap-a-round lines making a circle at the top mark intersection (short side of the cut).  Having an assistant to do the actual marking is handy since this will take both hands to hold the wrap-a-round. Also having your assistant to pull the circle with a finger makes for a better cut.  Do the same as this on the bottom intersection but turn around and go the other way, coming to the middle.  Now you should have the 45 degree cut line marked out.Make the cut, grind it pretty without changing the angle, then check the angle with your tri-square for 45 degrees.  Once right and good cut is established then make a template of it using some good gasket material.  This gasket material must be longer than the cut by a few inches and exactly long enough to reach around the pipe - intersecting exactly on your top mark line.  That way the next cut can be make by creating the top line, measuring where the short side of the cut needs to be, then marking around the pipe using your template.Its been many years since I'd did that but best I remember thats all correct.  Its hard to explain how to hold the wrap-a-round to actually mark the cut.  Its like - hold a length of the wrap-a-round with each hand and bend what sticks out the front into a half circle.  Your hands are 4-1/2" apart in this case and the half circle is raised at a 45 degree angle in front of you.  You hold this setup on your pipe and your assistant, with his finger, places the half circle on the top line and dimension mark, while you lower your hands so the wrap-a-round intersects your middle and side lines, then mark the top half of the cut line.  Turn the pipe over, turn yourself around, and do the same things again and mark the bottom half of the cut line.  these two intersects at the middle marks and lines.  The cut line, if done properly, is right.good luckLast edited by slowhand; 10-11-2010 at 08:25 PM.