Fabrication and Technical Solutions

  Engineering drawing abbreviations and symbols Abbreviation or symbol Definition Description 0-9 [ edit ] A [ edit ] AC across corners Commonly used when measuring the corners of a hex drive, such as a hex nut. AF across flats Commonly used when measuring the flat surfaces of a hex drive, such as a hex nut. AFF above finished floor A dimension that establishes a distance away from the finished floor. Example would be the top of a coffee table to the shag of the carpet, not where the bottom of the tables feet dig in. AISI American Iron and Steel Institute The AISI acronym is commonly seen as a prefix to  steel grades , for example, "AISI 4140". The  SAE steel grade system  was formerly a joint AISI-SAE system. Al  or  AL aluminium ALY alloy AMER American Referring to the  United States AMS Aerospace Material Standards Standards in  materials science and engineering  maintained by  SAE International  and widely used in the  aero...