ISO 7089Flat washer
ISO 7089 M20 Flat washer
ISO 7089 M20 is a flat washer, on a M20 × 1.5 mm metric thread. The general purpose flat washer. It protects the clamped surface, bridges oversized holes and spreads load under the head or nut.
Diameter20 mm
Pitch1.5 mm
Inside Ø d121 mm
Outside Ø d237 mm
Thickness h3 mm
Dimensions
- Standard
- ISO 7089
- Type
- Flat washer
- Size
- M20
- Thread
- M20 × 1.5
- Total height h
- 3 mm
- Inside diameter d1
- 21 mm
- Outside diameter d2
- 37 mm
Nominal values in millimetres as published in ISO 7089. Estimated weight 17.164 g per piece in steel (17.274 g in stainless), calculated from the nominal geometry — real parts vary with tolerance and head chamfers.
Thread data
Full M20 thread pageDesignationM20 × 1.5 fine
Pitch1.5 mm
Major Ø20 mm
Pitch Ø19.03 mm
Minor Ø ext18.16 mm
Tap drillØ 18.5 mm
Other lengthsISO 7089 M20
All M20 specificationsInterchangeability
ISO 7089 is catalogued with DIN 125 A as its equivalent designation. Dimensions are compared field by field rather than assumed identical.