.1/4" x 9/16" x 1/16" Black Rubber Grommets 20PK They may be used to reinforce the hole, to shield something from the sharp edges of the hole, or both.
.Sheet Metal Screw, #4 x 1/4 in, 18-8 Stainless Steel Flat Head Phillips Drive, 50 PK Sheet metal screws make excellent fasteners for attaching metal hardware to wood because the fully threaded shank provides good retention in wood.