How close to the end can you cut copper stub-outs for a compression fitting?

[Rossn]

Hello,

I am installing some radiators, and using the Uponor 3-1/2 x 8 ProPex copper stub-outs (https://www.supplyhouse.com/sh/control/product/~product_id=LF2865050)

I'm a little tight on length, and may need to get longer ones, though timing would not be ideal.

How close to the end of this stubout can I safely cut for a compression fitting? 5/8"? 3/4", 1"?

 

[Rossn]

Maybe 1-1/16" is a as close as I can practically get, based on my tubing cutter guide-wheel, since the discolored section bumps out slightly.

 

[Sponsor]

 

[Reach4]

I am not a pro. I was thinking 3/4 after looking at your first photo, but you make a good point on the cutter roller.

I like the Ridgid 101 "tubing cutter" for copper. It is compact. I don't know if it has a narrower roller. You can use a fine-blade hacksaw, and then clean it up.

 

[Mliu]

You don't have to use a rolling tubing cutter. If you really need to get as much length as possible, use a fine-toothed hacksaw just inside the heat-colored band. As long as the tubing is straight and not bulged, the compression fitting will slide on. You can wrap a piece of masking tape around the pipe (on the inside of the cut line) as a cutting guide. Saw gently so you get a straight cut and so that your saw doesn't jump out of the cut and scar the sealing area of your compression fitting.

Remember: If cutting with a hacksaw, you absolutely MUST deburr the inside and outside of your pipe, and you MUST flush out the copper chips (swarf) from the pipe before installing the angle stop valves.