- Two types of washers are specified in the ANSI standard, Soft and Hardened. Soft washers are generally used in low
strength applications to distribute bearing load, to
provide a uniform bearing surface, and to prevent
damage of the work surface. Hardened washers are intended primarily
for use in high-strength joints to minimize embedment,
to provide a uniform bearing surface, and to
bridge large clearance holes and slots.
An overview of suitable combinations of ISO metric plain (flat) washers and bolts, screws or nuts in respect of property (hardness)
classes and product grades is given in the following chart.
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METRIC FLAT WASHERS ACCORDING TO ASME STANDARD |
Washer
Size |
Washer
Series |
Standard |
Inside Dia (A) |
Outside Dia (B) |
Thickness (C) |
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Max |
Min |
Max |
Min |
Max |
Min |
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Note 1: Dimensions are in mm.
Note 2: Nominal flat washer sizes are intended for use with comparable nominal screw or bolt sizes.
Note 3: The 18.80 / 18.28 and 25.40 / 24.88 mm outside diameters avoid washers which could be used in coin
operated devices. [ANSI B18.22M]
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METRIC FLAT WASHERS ACCORDING TO ISO STANDARDS |
Washer
Size |
Washer
Series |
Product
Grade |
Standard |
Inside Dia (A) |
Outside Dia (B) |
Thickness (C) |
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Max |
Min |
Max |
Min |
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Min |
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Note 1: Dimensions are in mm.
Note 2: Nominal flat washer sizes are intended for use with comparable nominal screw or bolt sizes.
Note 3: Normal-series, product-grade-A flat washers chamfered at the outside
diameter are available for nominal thread diameters ranging from 5 mm to 64 mm
inclusive. [ISO-7090]. For a selected nominal size, inside & outside diameters and thickness values for chamfered
washer (ISO-7090) and non - chamfered washer (ISO 7089) are same .
Note 4: Nominal sizes available in this calculator are preferred dimensions given in ISO standards. For non-preferred dimensions, check ISO standards.