what is a flange for in a door
A flange is an external or internal ridge, or rim, for strength, as the flange of an iron beam such as an I-beam or a T-beam; or for attachment to another object, as the flange on the end of a pipe, steam cylinder, etc., or on the lens mount of a camera; or for a flange of a rail car or tram wheel. Thus flanged wheels are wheels with a flange on one side to keep the wheels from running off the rails. The term flange is also used for a kind of tool used to form flanges. Pipes with flanges can b