pivot screws, how do you find new ones?

[sogflash]

I have a cheap balisong trainer I'm thinking about giving away, but first I'd like to make it a little bit better.

one of the screws, or the cylinder it's in, has lost it's threads. how do I find new ones? I need to measure it, but I have no idea what to search for. what are they called exactly? the easiest way for me to buy some would be from ebay.

 

[Skimo]

The only place I know of that might have that would be knifekits.