​WP stands for Waite Phillips, one of the 3 brothers that founded Phillips Petroleum.  He later sold his shares in that company to his brothers, moved to Tulsa, and started his own business.  He built two office buildings in Tulsa, both of which have WP doorknobs.  First was Philtower, and 2 years later the Philcade.  This knob is from the Philcade.  His Tulsa home is now the Philbrook Art Museum and is New Mexico ranch is now the Philmont Boy Scoutcamp. Click on each photo below to view additional images and information.