Fishmouths??

[SSdoxie]

I have used about every method mentioned above and found the quickest/easiest for me is notch with the angle grinder.

 

[whateg0]

...Can you use a hole saw at high speed? I was under the impression that steel had to be drilled at slower speeds (>350rpm), is this not the case? ...

Ed

I usually just use the angle grinder to do mine, or if I have a bunch, the bandsaw. The reason for cutting (and if you are using a holesaw, you are cutting, not drilling) steel at the lower speeds is to preserve the cutting tool. Too fast, and you'll ruin the cutter. It isn't the RPM that is important, though that is the final number you need in order to setup the drill. It's the linear speed of the blade.

Here's a page that has a couple of quick formulas.
How to choose the right drill speed

I printed out a spreadsheet and have it attached to my lathe and mill for this. Pretty handy to have.


Dave

 

[Shield Arc]

I've used my mill and a roto broach before on small pipe.

 

[Egon]

Some welders have templates.

 

[Shield Arc]

Like these?

Shur-Kut

Products | PipeMaster - The Welder's Tool for Contour Fits

 

[Egon]

I was back in time with just plain magnetic templates that were used to trace the pattern. Most fellows did not have them or just a few for very common sizes they worked with.

But almost all had the guides for a straight torch cut.

 

[bikerdib]

If you're going to do it with hand tools, this is a nice template maker. Plug your numbers in, print it out, cut the line, wrap around your pipe, mark, and cut / grind.

Tube Coping Calculator

Wow Shield Arc, that's a nice calculator; thanks! I've always done it by the trial and fit method with a torch then finished up with a grinder. That will help a lot.

 

[Iplayfarmer]

I've never done it, but I have read where you can cut fish mouths with your chop saw. A guy posted these angle for the size pipe you're working with on another site.

Pipe / Tube bevels

2.0" to 2.0" tube, base angle of 30*

1.75" to 1.75" tube, base angle of 28*

1.5" to 1.5" tube, base angle of 26*

1.25" to 1.25" tube, base angle of 22.5*

1" to 1" tube, Base angle of 20*

Now to fit different size tubes together

1.75" to 2" tube, base angle of 25*

1.75" to 1.25" tube, base angle of 45*

1.25" to 1.75 tube, base angle of 20*

1" to 2" tube, base angle of 12*

I suddenly now feel the need to build something out of pipe.

 

[crazyal]

If you do it on a semi regular basis I would get the cheap pipe notcher. Doing 90 degree notches with a grinder is fine but once you start getting into angles, say building a roll cage, that's where the notcher really shines. They have a scale and are adjustable (think mine goes from 90 down to 30 degrees). Losen a couple of bolts, set to the correct angle, tighten, no real thinking involved. I've gotten hundreds of cuts out of a single hole saw, just low RPM and a little cutting fluid or WD40, cuts real fast.

 

[Rancher Ed]

I don't see doing it on a regular basis, just wanted to know how to do. (cause I like to know how to do things, and, I want to build a couple gates) I also now know of more things to add to my dream shop list. I will keep an eye out for a notcher though, it sounds nice.

Our drill press has a 1 1/8 hp motor but its min speed is 700rpm (it is made for wood) and it looks like that would be two to three times too fast for a 2" hole saw.

Shield Arc, if you want to donate a mill and teach me how to use it that would be wonderful:laughing:

Ed