This is a standard thumb screw for a Tripod
14 mm head with a 1/4 #20 thread. This the right thread size for common camera mounts but you might thing wise while reaming it in the first time. Stick with it. :)
I also included a "Shorter" version, I had one camera that had a shallow mount on it.
I used PLA and it worked wonderful.
ABS is MUCH easier and seems to cut the threads better too.
Nylon might be the BEST.
Print with no supports, 100% infill, and .1 mm layer height.
When working the threads the first few times, work it in 1/8 turn, then back about 1/8 turn each time. Repeat until the screw reaches the bottom. I used a rag on the screw head to NOT cut your skin to shreds when doing this the first time! The screw head groves are awesome once this process is done. You will curse them when cleaning up the threads the first time. You will understand the first time you are screwing this in! Once you hit the bottom the first time, each time in is really smooth.