Rack mount screws for data racks are commonly available in two sizes, #12-24 and #10-32. ICC patch panels come with 12-24 rack screws. 12-24 threads are designed into most data racks. 10-32 threads are designed into Dell Equipment and most audio racks.
12-24 Threaded Screw – ICACSS01BK – active
12-24 is more common than 10-32. 12-24 fasteners are slightly larger than 10-32 and have courser threads. The term 12-24 comes from the Unified and American Screw Threads for Bolts, Nuts, and Machine Screws standards published by ANSI B1.1-1974. The number “12” is a size designator. The number “24” refers to 24 threads per inch. You can identify a 12-24 screw by measuring the diameter with a ruler at slightly less than 7/32″ (slightly larger than 3/16″ or 0.216″).
10-32 Threaded Screw – ICACSS02BK – obsolete
10-32 threads are historically the original rack screw type. The term 10-32 comes from Unified and American Screw Threads for Bolts, Nuts, and Machine Screws standards published by ANSI B1.1-1974. The number “10” is simply a size designator. The number “32” refers to the 32 threads per inch. You can identify a 10-32 screw by measuring the diameter with a ruler at exactly 3/16″ (0.1875″).
ICACSS01BK