Here are the different size pins that are most common:
Quick Release: This is the screw for assembling and disassembling your cue quickly. Just a few twists unscrew this pin. A few threads wrap around the head of a smooth metal rod.
5/16-18: This size pin is somewhat popular. It’s often paired with a flat-faced joint.
5/16-14: Another common pin size, these screws are usually used for a piloted joint.
3/8-10 and 3/8-11: A fatter joint pin, this screw usually screws directly into threads cut into the shaft. Threads wrap around the entire pin.
Radial: Typically screws into wooden threads. A smooth area in the middle of the pin separates the threads wrapped around both ends.