Hot off the press, two clamp mounts printed from Thiniverse.com that use a 1/4 inch bolt (or threaded rod), wing nut and regular hex nut to make an amazing tripod mount for an iPhone or any smart phone, small tablet, etc (would not suggest for iPad even though it could work, there isn’t enough surface area). Wish I could remember the link and would post as I was not able to find it again when we went back and looked for it to add here.
Here you see the 1/4 inch bold and win-nut. Pressed inside is the 1/4 (20 turn) hex-nut which mates to the tripod screw. The again is an amazing and simple design as each are a mirror of one another so just copy twice and you have the build! This is what 3D printing is all about was one evening we needed a quick and dirty tripod mount for an iPhone 4s and downloaded this STL file and 30 minutes later we solved the problem (we printed rough and fast).