Grease cup

An assembly comprised of a small metal cup with internal threads that could be screwed down over a threaded base plate that was screwed into the housing of the mechanism to be greased (usually a bearing). The cup was packed with grease. When screwed down it forced the grease through a hole in the base plate and into the mechanism to be greased. Grease cups have largely been replaced by Zerk fittings and a grease gun that can force grease under pressure into the Zerk fitting and thence into the bearing. The means to inject grease under pressure using a gun and Zerk or comparable fitting was often called an Alemite system.