How-To: Make Perfect Saddle Cuts

Speaking of saddle cuts (e.g., TM drum smoker post on 1/18/2010), Instructables has a new posting on making perfect pipe saddle cuts with a bandsaw or chopsaw. For same diameter pipes, the author, samson3000, uses two cuts at approx. 35° close to, but not through, the center of the pipe so there’s a flat spot (as shown above), not a sharp point. An end view of the cut, pictured below, shows a pretty tight saddle.

For a larger pipe saddled to a smaller pipe in the case where the smaller pipe fits in the larger pipe, the angle is increased to 45°, and the cut goes through the center, so there is a point. If you want a non-90° saddle, you can, for example, cut one side at 30°, and the other at 45°. There are many machine-shop illustrative pictures at the Instructables link.
Making Perfect Pipe Saddle Cuts [Instructables]
As a carpenter who likes to tinker with metal occasionally (my father was a welder, maybe it’s in the genes!), I want to offer a hint for this process. Making the angle cuts to a point first, and then squaring of at the proper location is a better plan. The heel of your angle cuts will be the measuring point, and is more important re: accuracy. A goof on the square cut can be dealt with easier.
You can also use the Tube Coping Calculator at metalgeek.com to print wrap around templates for more complex joinery. There is also a downloadable program TUBEFIT that works for sizes that are beyond the constraints of the web based utility.
I saw that Instructable and it’s nice, and it looks like a really good method for most purposes, and it’d be good enough for anything I’d be doing, but it sure ain’t how you make “perfect” saddle cuts.
@ David
I was a little uneasy about the “perfect” part myself, but decided to stick with the title from Instructables to be consistent.
That looks like cast iron pipe.
Harderwoods.com has a nice cope template generator I’ve used a couple times.
As an apprentice, I needed to learn how to make cope templates with drafting tools, and it’s saved my butt a couple times. You can find the method in a book on sheet metal pattern development.
If you have to make a pile of cope cuts, make your first piece with the chop saw method, make it perfect, then make a template by wrapping a piece of paper around it and rubbing the cut edge with your dirty hands; it will transfer the edge to the paper quite nicely. Trim ‘er up and you have a nice, accurate template.
Oops, I forgot to put my website in my post!
By the way: I haven’t seen the term fish-mouth used anywhere…Isn’t that what American fabricators call them?
Let’s not start name-calling! lol
Take a look at ‘www.pipesaddlelayout.com. The saddle page gives the layout lengths in seconds for various pipe sizes and different angles. It gives the basic 8 ea. lengths for the typical 16-division layout; in addition it gives the dimensions for a 64-division layout in case you have a very shallow angle or want more of a template quality layout.
I cannot open the pipesaddlelayout.com it has ads and I cannot find the info you refer to. Can you help