How do I know what size joint protectors to order for my break cue?

If it looks like a regular screw, you can measure it. Most will be 3/8" or 5/16" diameter. Then count the number of threads per inch, which will be the second number, usually 10, 14, 16, or 18.

If it doesn't look like a regular screw, it could be radial, uni-loc, or some other custom pin. You can take a picture of it and I'm sure someone will be able to identify it.

Otherwise, if you know the manufacturer, most use a certain pin. See the site below for some common ones. If you know the model of your break cue though, you can search for it on the internet and maybe one of the descriptions will have the pin size for you.

Pool Cue Joint Protectors

Get Joint Pain Relief Codes!

i wish you would of told me what the name of your cue is, could of told you easy. most cues are 5/16-18 thread...if its wood to wood joint, its 5/8-10. if its really a good cue, like predator, its 5/16-14. i would bet its 5/16-18. but take it to a pool hall or dealer, someone will know as soon as they see it. gl.sir.

Never really thought about this