Okay, I'll give you a differing opinion. I hate liner locks -- but partial engagement is usually not a reason I'd send the knife back, at least not until I try to work things in myself.
The thing about titanium liner locks is, there's often a very fast break-in period, where the liner wears very quickly and it moves inwards towards the tang center. If the liner comes out of the box already fully engaging the blade tang, it will march across the blade pretty quick during break-in. If it's not quite engaging the entire blade tang, I find that after a quick break-in, it's engaging perfectly.
How do you break in the lock? Open it 50 times, somewhat hard. YOu don't have to slam the thing open as hard as you can, just get some good force to get some wear on the locking leaf. If the lock was executed really badly, even after break-in it still won't be engaging the tang -- in that case, send it back. But it many many cases, breaking it in is all you need to do. Plus, the lock sometimes seems to get more secure after a break-in, so your liner lock could end up more reliable than someone whose lock engaged perfectly out of the box and who subsequently didn't break the lock in!
The other concern people sometimes have is that they feel that if the liner lock is engaging in the exact center of the tang, it will be more reliable than one that engages left. This isn't my experience at all. The reliability often has to do with the angle cut into the back of the tang, and if that angle was well-chosen, the lock will be absolutely solid even if it's engaging way left. Whereas if that angle was chosen badly, the liner will be unsafe no matter where it engages. Besides, the liner moves across the tang naturally as it wears, so it'd better be solid across the whole range!
Joe
