Drill a hole in the end of a yardstick. Then saw off a few inches, and sandpaper or file rough edges + corners.
It's usually better to drill the stock while it's long, so there's something to hold/clamp. Short pieces have a tendency to spin with the drillbit. It's safer to drill the stick while it's long.
Now you have a convenient portable way to mount your phone-cam. Useful for hiking, or documenting instructables. The best camera, as they say, is the one with you.
Here's a pic from my other instructable: https://www.instructables.com/id/Pocket-Tripod-Mount-for-mini-Video/
Aluminum is nice, and would work well for the cell phone mount. I was out of it, however, which is why I used the wingnut + yardstick.
This sort of device really helps when making an instructable that you want both your hands in picture. You don't have to hold the phone/ camera in your mouth, nor enlist someone's help.
Please don't consider this last step as part of this -ible. Vote only as far as the wood-string-wingnut project goes. I missed the deadline with the aluminum one, but wanted to include it as an option for you folks. It certainly will be more durable.