Locksets for entry doors.

I saw a discussion about using ordinary locksets on a tear but they are designed for doors of normal thickness. What is being used for 3/4' plywood doors. I have seen lockable sets for screen doors but don't consider that little spring loaded flipper bar they use very secure. When we had our pop-up though it just had a flimsy lock and of course anyone wanting in could go through the canvas by seperating it from the door. Never had a problem, I've found most people in campgrounds to be honest folks. But I still need a latch of some sort.