My concern was would the 4 wood screws over time work loose. I have not had a problem with any of my other locks but none of them have anywhere near the weight that are on these two shelves. Also none of the other shelves face a direction that make them want to move when I start and stop. To help with this problem I added 2 1/4 inch bolts with a big washer and a lock nut. I dont think this will come apart.