Rack Mount a PC Horizontal
Most desktop PC’s are not designed to be converted into a rackmount server. Sliding rail kits are simply not an option due to the design of the chassis. In most cases the PC can be placed on it’s side on a shelf, that is if it does not exceed 17.7″ in width, which is the opening of an EIA standard 19″ rack.
Rack Mount a PC Vertical
If the PC is in fact wider than 17.7″, another option is to stand the unit upright on the shelf. In this scenario, you can actually place 2 PC’s side by side, again that is if the overall width of both does not exceed 17.7″. Of course, not all PC’s weigh the same so make sure to weigh the PC before purchasing a rack mount shelf. Below are a few options of sliding shelves.