What is BS 869 - Specification for toolmakers’ flats and surface plates about?
BS 869 is an International Standard that discusses the technical specifications and uses of toolmakers’ flats and high precision surface plates .
BS 869 applies to circular hardened steel toolmakers’ flats that have a maximum diameter of 200 mm, and to cast iron or granite high precision surface plates which have a maximum diameter of 400 mm.
BS 869 discusses toolmakers' flats that are of high-quality steel, free from inclusions, and are made from hammered and upset blanks.
The working surface of the flats and plates described in BS 869 is finished by high-grade lapping2) free from noticeable scratches.