This area is to discuss slot machines. A slot machine is defined as a machine that pays the customer something of value (coin, token, etc.) when a winning combination is hit.
It's probably a common bolt size. Your local hardware store could probably fix you up. Just measure the diameter of the hole to get an idea of what you need. Then when you get one look inside the hole and see if the space between the threads looks like the set screw you bought. Just go easy screwing it in in case it doesn't match.