Locks for underfloor trunk storage

I followed several older threads on locking the cover of the trunk storage box, with no clear answer as to how to do it (maybe I missed something?). Someone mentioned a cam lock, and I went from there.

Here's how I did it, removing the folding cover from its front-of-vehicle notches so I didn't inadvertently get the cover locked in a position where I couldn't get it to open!

1. Remove one (or both) of the locking knobs by unscrewing the philips holding the locking arm. The know then pulls right out. Reassemble and save to put your car back to stock condition if needed.
2. You will see a somewhat quarter circle hole.
3. Buy a cam lock (e.g. from a hardware or home supply store), looking for a short one (for max 1/4 inch material). I used a First Watch 1358 from Lowes. You can try to match the thickness from the bottom of the original knob to the arm with the new lock ... the 1358 matches perfectly.
4. With a shop file, enlarge the hole by expanding it top and bottom (side to side is already ok) ... you don't need to take off much material for the cam lock to fit in. Take some material, try, take more as needed. DO NOT drill a full 3/4 hole as the lock will tell you to do, since you want the existing narrow side of the hole to keep the lock body from turning and the lock being easily unlocked with the twist of a screwdriver.
5. CAUTION: when you disassemble the cam lock, keep one key in it to keep it from falling apart!
6. Use the longer straight arm, from which you will have to cut about 1/8 inch, no more. Maybe try before cutting, but I needed to do this for the lock to engage and emerge from the existing slot for the original locking knobs.
7. Assemble the lock with the 1/4 turn washer in the proper orientation. You can use the toothed washer (teeth upward) to add to the lock body not turning.
8. Test everything with the front (of car) part of the cover folded over so you can reach inside and see that the lock is engaging properly and most important, unlocks!

These light-duty cam locks will not stop a determined thief, but are obstacles to a quick grab and run, as well as having a locked compartment for carrying anything that will fit and legally has to be locked.

I was surprised how easy this was - a half hour not including shopping for the lock.