Most balisongs, especially with T-latch, are made to only be opened/closed if you squeeze the handles a bit and then engage/disengage the T-Latch. My benchmade 42 is like this. This is so that when the latch is engaged in the opened or closed position that the latch doesn't simply slip loose. Sorta like a functional friction lock holding the latch in place. If you couldn't even squeeze the handles together to engage the latch, something was wrong. Of you filed the handles and the latch is loose now and doesn't stay engaged in the open and closed positions, you probably messed it up lololol. You really don't want that thing opening on you in your pocket. That's why they're made to only open if you apply pressure and squeeze the handles in the open and closed positions.