new hardware for blocks

Well, I've lost the mounting hardware for my videocard block and rather than buy new stuff from DD for it, I'm thinking I should just be able to go to Lowes/Home Depot and pick me up some. I still have the posts but I'm missing the plastic washers and springs. I'm sure they would they have small enough springs there. What section should they be under?

i found hobby springs in home depot in the aisle with screws, bolts and specifically next to an area of things for hanging stuff on the wall. there wasnt much of a selection, and i ended up not getting them. i was too worried i would either crush something, or not get enough pressure.