05-05-2016, 11:38 PM
You can get a tool at the hardware store, Sears etc that will measure threads. It looks like a little set of combs with teeth. If you had a set of tap and die's it would probably come with it, mine did. then you can find the right size teeth to fit the threads in the hole and it will show you the size threads. If no one knows what it is you should look for one of those measuring tools.