I couldn't find the cellphone holder I had made before and only had a couple of hours to get to where I wanted to make a video so I came up this this. The materials are simple:
A metal coat hanger or a fairly stiff metal wire
A 1/4"-NC 20 nut (or whatever nut fits the threaded mount)
Tape for padding (optional)
I'm not going to build a new one and show the process as this is pretty simple but it took about fifteen minutes to make.
Step 1: Attaching Holder to Tripod
There are no dimensions because each cell phone is different and you can make it for each phone you have. This is made to hold the phone sideways but if you want it upright then just make it longer.
The first thing to do is bend the wire to that it fits around the threaded tripod mount, then test it by putting the nut on it. This and the next steps were done off of the tripod as it was easier to do that way. When making this the wire would just be a very long and narrow U at this point with no other bends.
Step 2: Make a Right Angle Bend
Once the holder fits then bend the wire into a right angle at the bottom. The wires curving down in the front would still be attached to the coat hanger and be pointing straight up.
Step 3: Make a V
Now take the upright wires and angle them out like a V which will eventually turn into an M
Step 4: Turn It Into an M
Now take your phone and figure out where you want to bend your wire over them. Remove phone and bend the wires into an M. Then cut the wire just below the camera. The phone should slide in and out with a slightly tight fit. If the holder is not quite the right size you can easily bend the wire to make it work. You can also put in padding or tape the wire.
If you want the phone to stand upright then just make the M higher and the V narrower.
I used it and the phone didn't move or vibrate so it works quite well.