Plumbing – What size is an ice maker connection

The easiest way to achieve what you are looking for with what you already have is to:

1. Shut off the water at the angle stop shown in your first photo (confirm that the valve is closed by opening the cold on you sink)
2. Cut the copper tubing in half (the tubing between the angle stop and the second valve)
3. Install the valve tee shown in your second photo (this will reconnect the cut tube)
4. Test (by opening the angle valve)
5. Slowly tighten the compression fittings if they are leaking

Here's a video on how to install compression fittings: Youtube video.

This is an Drop Elbow (upside down for your use), most commonly used for wall penetrations...showerhead arms, tub faucets, washing machine supplies, etc. I don't know of any other types that you'd actually screw to the floor & haven't ever seen one.

Presuming your hole is tight to the wall or baseboard, you might be able to attach this to your wall or baseboard with either a direct connect flexible line or a single compression fitting. Anything more would likely get crushed by the fridge. But a screw in elbow fitting to convert to vertical may work for your situation. However, elevating the fridge's tube connection that's already set-out much may put it in threat of being crushed, so be careful & test it out gently.

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Male solder-on or sweat-on. My preferred floor lock-in fitting. Threads are exposed for thread inspection, easy Teflon taping, more precise leak detection, female reducing adapters are more common & flexible lines come with direct attachment ends.

Female solder-on or sweat-on. Nothing really wrong with this. I just don't find much of a selection to accommodate it in the big stores.

All three would be first soldered onto the pipe you drop in the floor. It's ill-advised to feed a pipe up & then later solder on a fitting that's close to a wall, especially when so easily avoidable.

Your pipe or elbow beneath the floor would prevent or limit vertical movement & a hole drilled for the pipe diameter instead of for the fitting's shoulder would raise the fitting for easier future flexible line replacements & stop downward movement to avoid stressing of the piping beneath the floor.