FLAT WASHER DIMENSIONS (INCH SERIES)

Flat washer dimensions are shown in the following chart according to ASME B18.21.1-2009 standard. Flat washers from #0 to 3 inches nominal size with A and B types are covered in the chart.

The Type A flat washers serve to minimize embedding and to help tightening. The Type B flat washers fulfill the customary purpose of distributing load over larger areas of lower strength materials.

Some important notes from the ASME B18.21.1:

- Flat washers shall be made of low carbon steel, stainless steel, non-ferrous metal, plastic, or other material as specified by the purchaser. The tolerances given by the calculator are intended for metallic washers only.

- Hardened flat washers shall conform to the chemical and mechanical requirements in ASTM F 436.

Calculator:

INPUT PARAMETERS
Nominal flat washer size

 


Dimensions of Plain Washer
RESULTS
Washer
Size
Type Series Inside Dia (A) Outside Dia (B) Thickness (C)
Basic + Tol -Tol Basic + Tol - Tol Basic Max Min
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Note 1: Dimensions are in inches.
Note 2: Nominal flat washer sizes are intended for use with comparable nominal screw or bolt sizes.
Note 3: The 0.734-inch, 1.156-inch, and 1.469-inch outside diameters avoid washers which could be used in coin operated devices.
Note 4: Most part of the preferred sizes for Type A plain washers are from series previously designated “Standard Plate” and “SAE.” Where common sizes existed in the two series, the SAE site is designated “N” (narrow) and the Standard Plate “W” (wide). These sizes as well as all other sizes of Type A Plain Washers are to be ordered by I.D., O.D., and thickness dimensions.

Reference:
  • ASME B18.21.1-2009, Washers: Helical Spring-Lock, Tooth Lock, and Plain Washers (Inch Series)