Thread sizes come in various sizes. Their sizes range from small to large thread sizes. You can find threads of 5/8-inch with 27 threads per inch, and this is a unified special thread used in the United States. and the rest of the world.

Furthermore, you will find a ½-inch thread with 12 threads per inch. Older European stands made use of this type of thread size. Moreover, you will find 3/8-inch thread with 16 threads per inch. This thread size is not standard in the United States, but other parts of the world use it. 
Use a #7 (5.1mm) drill bit. A 5mm drill bit should work. ;)

Lastly, you will find a ¼-inch thread size with 20 threads per inch. This thread size is also not a common standard in the United States, but other parts of the world use it. It is also common among photography tripods.