The slot for the o-ring is in a particular area. If you try and machine something new into yours, you will change the geometry to how it all works. Could make it worse. That part is fairly cheap so look into getting a newer used one with the groove and I am assuming this is for a berk right? If your bowl is scored heavily...might need to get the over sized ring and put a rubber band down first or pipe thread tape to fill the void in bowl.

Unfortunately my funding is pretty low and I really want to fix rather than replace any thots or info would be greatly appreciated.. I think I'm going to try a hard plastic molding with a rubber expanding tip.. :/