

These are larger and stronger than the #10-32 screws.

Tapped-hole racks are used for hardware that rarely changes, such as phone, network cabling panels, TV broadcasting facilities, studios and relay racks. The hole pattern thus repeats every 1.75 inches (44.45 mm). Vertically the holes in the posts are arranged in repeating sets of three, with center-to-center separations of 0.5 inches (12.70 mm), 0.625 inches (15.88 mm), 0.625 inches (15.88 mm). The posts have matching holes in them at regular intervals, with a center-to-center distance of 18.312 inches (465.12 mm). The posts are each 0.625 inches (15.88 mm) wide, and separated by a gap of 17.75 inches (450.85 mm), giving an overall rack width of 19 inches (482.60 mm). A standard 19-inch rack is 84 HP wide.Ī rack's mounting fixture consists of two parallel vertical metal "posts" or "panel mounts". HP (horizontal pitch) is the unit of length defined by the Eurocard standard used to measure the horizontal width of rack mounted electronic equipment.

RU (rack unit) or U is the unit of measure used to describe the height of equipment intended for mounting in a 19-inch rack.
