What shelf pin system do commercial bookcases use?

Commercial bookcases use 1/4" or 5mm pin holes drilled in 1"–2" increments along the interior side panels — the 1" increment gives the finest adjustment. Shelf pins are typically 1/4" diameter steel pegs, so order replacement pins with the matching diameter. FindOfficeFurniture.com includes extra shelf pins and ordering specs with every bookcase — call 888-719-4960 if you need compatibility guidance.