Flat Washers - Imperial

Imperial washers are classified in tables, from Table 1 to Table 4 with an additional number that denotes the outside diameter. A brief explanation of the differences is as follows;

  • Table 1 - Used in conjunction with imperial BA threads (British Association). Classed as small.
  • Table 2 – Also used in conjunction with imperial BA threads but classed as large.
  • Table 3 - The most common imperial washer and very similar to metric Form A
  • Table 4 – Larger in diameter than Table 3 and similar to metric Form C

The main purpose of a flat washer is to spread the force that is created by the tightening of a nut across a wider surface area.

Imperial flat washers are also occasionally used as spacers, they are useful for this purpose if the bolt being used is slightly too long for the application in question.

If you need a washer with a larger diameter choose a repair washer.