Tube flaring bit - GIF

[metric_taper]

Aside from original use of emt, simple socket joints would have no end of usefulness in emt.

I did not articulate that very well, but that was my point. I can't think of a non electrical use where swaging the pieces together would be of value, but mlochala may have some application.

I have the old style swaging tool where you use your flaring block to hold the copper tube, then wack the swage tool with a hammer. The benefit of this tool is it appears to burnish the copper. Where I've seen them used is on youtube videos where the HVAC tech is replacing compressors or filter dryers, and fitting in the tubing stubs to the existing system without using couplings.

[mwmkravchenko]

If you are thinking of making this all you need for size is a female copper connector. That will give you the O.D. that will work best. A tight O.D. measurement of a piece of copper pie will end up biting you in the ass later.

It doesn't have to be anything exotic. A decent grade bolt is way more than you will ever need to hold up in soft copper.