eyball the size of that bolt and get to home depot, go into the area with all the bolts and stuff..and look at they're bolt sizing chart and buy all the nuts that look like they could fit...they're probably only like 4 to 6 possibilities, probably a "fine" and a"course" thread type. Just buy both thread types for all the sizes you choose Only like 50 cents a piece. And then return the ones that don't work. You should be fine. Unless you don' t have a home depot or lowes near, but who doesn't they're friggin everywhere..lol. When i loose nuts or bolts thats what i do. You have to go to the area with the drawers, thats all the metric stuff. Hope this helps and good luck!