An adjustable tripod mount and stand for phones, inspired by the Glif. It works, but I disclaim responsibility when your phone falls out of it. Buy a Glif.
Check out my remix that uses an M5 screw and supports portrait mode.
This uses a rubber band to provide tension in each of the end holders. The problem is, there is very little distance to work in, and it is difficult to attach the rubber band with enough tension. What ended up sort of working is to double up a rubber band, attach one end to an end post, thread the other end(s) through the tube (grab them with some tweezers from the far side), hook that end on, then twist to get even more tension. See the picture.
Make sure the holders go on the correct sides. The tripod mount should have two angled holders, the stand side should have two flat holders. See the assembled STL photo.
Place a 1/4"-20 nut in the end cap hole to use with a tripod. Gluing it in would be best.
All parts should be printable without support except for the rubber band posts.
This could certainly stand to be improved, so I have provided the DesignSpark Mechanical file.