Since 12L14 is an extraordinary machining steel it has become the favorite carbon metal for machining-especially on light weight lathes. It offers inherent ductility combined with finer surface quality. 12L14 has a smooth cold finish (rolled) surface.
1 An infection in the middle ear. When the middle ear is infected, pressure builds up and pushes against the eardrum and can cause the eardrum to perforate. When that happens, you may suddenly notice that the pain and pressure you've felt from the infection stops and pus drains from the ear.  An injury to the eardrum.
Perforation of the eardrum by an injury causes sudden severe pain, sometimes followed by bleeding from the ear, hearing loss, and noise in the ear (tinnitus). The hearing loss is more severe if the chain of ossicles has been disrupted or the inner ear has been injured.