What to do should the screws holding your knife together, start to back-out causing your knife to malfunction.
For the most part, today's knives are assembled using torque screws rather than using tubular rivets or solid nickel pins, this came about due to custom knife makers needing a way to assemble their knives the easiest way possible without having to purchase riveting machines or manually tapping a solid pin into a very small diameter hole that they would have to drill out, so they started using torque screws, these are readily available from any industrial supply retailer making the building of a custom knife a bit easier.
Nowadays , it's rare to find a pocket knife that is riveted, it's "old school" and that's fine, the market place has come to accept a knife that is held together by screws rather than rivets, but the screws do have one down side, just from ordinary use they tend to back out of their threaded axle, and this is especially true with a blade under load such as a switchblade. So, what to do? Once you notice the screw is coming loose, tighten it down to prevent losing it, if lost, finding the exact size and thread will be a real pain, doable, but time consuming. Next get some Superglue, this is readily available at any office supply store, Wal-Mart, pharmacy, dollar store, etc., you could use Locktite , but it's not as readily available as Superglue and Superglue works so much better, the only draw back, you may not be able to remove the screw again, but why would you want to?
Now, pay close attention, because Superglue works so well, only use a little, how much is a little? I mean just enough to cover a couple of threads of the screw, I know, doesn't seem enough, but that's all you'll need. Special Note, the key here is to open and close your blade as the Superglue dries, don't replace the screw and walk away leaving the Superglue to dry, you may not be able to get the blade open, ever! After replacing the screw with a the Superglue on only a couple of threads, open and close your knife, adjusting the tension on the screws to make sure the blade opens easily, you'll only need to do this for about 3 to 5 minutes, but well worth the time since you won't need to worry about the screw ever backing out again.
Hope this helps,