Abstract: An apparatus for producing custom orthotics includes a boundary wall encompassing a substrate pad and an overlying elastic skin to form an expandable interior chamber into which high density molding material is injected. A matrix of axially movable drive pins project through the pad and are urged upwardly into contact with the arch of the individual's foot to maintain the foot in properly aligned position during fabrication of the orthotic, the drive pins carrying a support bridge driven into conforming contact against the arch of the foot.