McMahon Steel is Southern California's leading fabricator and erector of structural steel and miscellaneous iron. Founded in ... 1970, McMahon Steel remains a family owned and operated enterprise. We specialize in the detailing, fabrication and installation of structural and miscellaneous steel for commercial and industrial construction projects throughout the Southwest. We are AISC and City of Los Angeles certified, and can take care of all your steel needs from the ground up. read more