True "experts" of a trade know those little "simple tricks" that make a job much easier. This is one of those tricks that makes working with pipe MUCH easier. I learned this wonderful way of making saddle cuts years ago, but only recently learned very few people know about this. So, I thought I would share. I know the first time it was shown to me, I said "That's amazing!" I can only hope your feel the same!
All you need to make wonderful looking and fitting saddle cuts is a bandsaw or chop saw.
I've made a video for this, and it's the last step. I think it's a bit easier to understand than photos.
Step 1: Setting Up for the Cut
I'm gonna show all this being done on a bandsaw, only because it is much easier to photograph. A chop saw or cold cut saw works just as well.
First, set the saw to 35 degrees. This does not have to be exact. 33 to 37 degrees should work, it will just change how much is cut off.
Get some scrap pipe, and set the pipe in the saw. Then adjust the length to be cut off. The cut will NOT be made in the center of the pipe, in this example, the blade is about 3/16 of an inch from center. One could use math to figure out the offset, but it doesn't take too many cuts to begin understanding how cutting off more or less of the pipe affects the saddle. But for now, don't worry about where you make the cut.
Once the pipe is tight in the vise, I use a C-clamp as a stop. When the pipe is turned half a rotation, the clamp will ensure the same length of cut is being made. On every chop saw I've used, it's impossible to use a C-clamp, so I use a sliding square, and measure in from the end of the vise. However, when the pipe is turned, the square will be in the cut. If precision is not needed, just eyeball across the end of the pipe to the end of the straight edge. Or, lay a strap iron across the end of the pipe. A bit more complicated and time consuming...
Step 2: Turn and Cut Again
Now, rotate the pipe half a turn, and cut again. With 35 degree cuts, there should be a "flat spot" between the two cuts, not a point. The width of the flat spot depends on the angle of cut, and the size of the pipe.
Step 3: A Saddle, and Two Vicious Pieces
After the second cut is done, that's it! You will have a wonderful saddle cut, and two vicious pieces of metal. I say that because these cut offs will go right through a shoe, or tire, air hose, extension cord....basically anything you don't want them ruining. Make sure they get put in the scrap barrel immediately!
If one cuts too MUCH off the pipe, (end up with a bigger scrap piece) the result is a "pointy" cut. This point will hit the pipe being saddled, and create a gap. If it's not too bad, a quick touch up with a grinder will correct it.
If one cuts too LITTLE off the pipe, (small scrap), the result is a wide flat spot that does not touch the saddled pipe. Sometimes this is acceptable, depending on the welding process, and use of the pipe.
But, what if the pipe is NOT of the same diameter? Well, on to the next step!
Step 4: Larger Pipe Saddled to Smaller Pipe
35 degrees work great for pipe of the same diameter, but saddles are often done on various size pipe.
If the pipe being cut fits over the pipe being saddled, then set the saw to 45 degrees.
Set the blade to cut on the center of the pipe.
Turn, and cut again, just like before, except the pipe will be pointed.
It will fit right around the smaller pipe!
I've showed you the basics, but this idea can be expanded upon. This works for non 90 degree saddles, too. Cut one side 30 degrees and the other 45 degrees, and see how it saddles.