Question: what is the difference between a #10 and #12 screw?
Answer: You can identify a 10-32 screw by measuring the diameter at exactly 3/16″ (4.76 mm). 12-24 rack screws are more common than 10-32 in pre-threaded racks. They are slightly larger and courser than 10-32 hardware. ... You can identify a 12-24 screw by measuring the diameter at slightly less than 7/32″ (5.55 mm).