Plain or large
ISO 7089 (formerly DIN 125-A) is the normal series, ISO 7093 (formerly DIN 9021) the large series: for the same bolt its outside diameter is much larger. A large washer goes on a soft part or over a large hole.
Reference tool — not a selection
Find a washer by its bolt size or by measuring it, before it goes in an RFQ.
ISO 7089, ISO 7093, DIN 127-B
Bolt size, standard or caliper.
Pick the type of washer and enter the bolt size or a designation. Without a designation, enter the measured d1, d2 and thickness in the fields below or as 13 x 24 x 2.5: a match is within 0.5 mm on the diameters and 0.2 mm on the thickness. Below, an offered washer can be checked against the result.
Examples:
Replacement check
On the designation alone: the material, hardness class and finish are checked separately.
All 130 engineering tools
Plain, large and spring washers sit under bolts and nuts all over a ship: on pump and valve flanges, engine covers, deck machinery and electrical cabinets. Pick the type and enter the bolt size with or without the standard (ISO 7089 M12, DIN 9021 M8, DIN 127 M20, spring washer M10), or the measured inside diameter, outside diameter and thickness (13 x 24 x 2.5): the finder gives the row of the standard, draws the washer to scale, checks an offered washer and writes an RFQ line.
The material, hardness class and finish do not follow from the size: give them in the request. Washers for bolts below M3 or above M36, and washers to other standards, are not in this finder.
How a washer is measured
Hole, outside diameter, thickness.
Spring washer
DIN 127-B is a split ring with flat ends and a rectangular section, s thick and b wide. DIN 127 is withdrawn, but these washers are still common in catalogues. A spring washer and a plain washer are not interchangeable.
d1, d2, h
d1 is the inside diameter, d2 the outside diameter, h (s on a spring washer) the thickness. The tables give d1 as the smallest the hole may be and d2 as the largest the outside may be, so a measured hole is usually a little larger and the outside a little smaller.
| Standard · size | Inside d1 | Outside d2 | Thickness h or s | Width b |
|---|---|---|---|---|
| ISO 7089 · M3 | 3.2 | 7 | 0.5 | — |
| ISO 7089 · M4 | 4.3 | 9 | 0.8 | — |
| ISO 7089 · M5 | 5.3 | 10 | 1 | — |
| ISO 7089 · M6 | 6.4 | 12 | 1.6 | — |
| ISO 7089 · M8 | 8.4 | 16 | 1.6 | — |
| ISO 7089 · M10 | 10.5 | 20 | 2 | — |
| ISO 7089 · M12 | 13 | 24 | 2.5 | — |
| ISO 7089 · M14 | 15 | 28 | 2.5 | — |
| ISO 7089 · M16 | 17 | 30 | 3 | — |
| ISO 7089 · M18 | 19 | 34 | 3 | — |
| ISO 7089 · M20 | 21 | 37 | 3 | — |
| ISO 7089 · M22 | 23 | 39 | 3 | — |
| ISO 7089 · M24 | 25 | 44 | 4 | — |
| ISO 7089 · M27 | 28 | 50 | 4 | — |
| ISO 7089 · M30 | 31 | 56 | 4 | — |
| ISO 7089 · M33 | 34 | 60 | 5 | — |
| ISO 7089 · M36 | 37 | 66 | 5 | — |
| DIN 125-A · M3 | 3.2 | 7 | 0.5 | — |
| DIN 125-A · M4 | 4.3 | 9 | 0.8 | — |
| DIN 125-A · M5 | 5.3 | 10 | 1 | — |
| DIN 125-A · M6 | 6.4 | 12 | 1.6 | — |
| DIN 125-A · M8 | 8.4 | 16 | 1.6 | — |
| DIN 125-A · M10 | 10.5 | 20 | 2 | — |
| DIN 125-A · M12 | 13 | 24 | 2.5 | — |
| DIN 125-A · M14 | 15 | 28 | 2.5 | — |
| DIN 125-A · M16 | 17 | 30 | 3 | — |
| DIN 125-A · M18 | 19 | 34 | 3 | — |
| DIN 125-A · M20 | 21 | 37 | 3 | — |
| DIN 125-A · M22 | 23 | 39 | 3 | — |
| DIN 125-A · M24 | 25 | 44 | 4 | — |
| DIN 125-A · M27 | 28 | 50 | 4 | — |
| DIN 125-A · M30 | 31 | 56 | 4 | — |
| DIN 125-A · M33 | 34 | 60 | 5 | — |
| DIN 125-A · M36 | 37 | 66 | 5 | — |
| ISO 7093 · M3 | 3.2 | 9 | 0.8 | — |
| ISO 7093 · M4 | 4.3 | 12 | 1 | — |
| ISO 7093 · M5 | 5.3 | 15 | — | — |
| ISO 7093 · M6 | 6.4 | 18 | 1.6 | — |
| ISO 7093 · M8 | 8.4 | 24 | 2 | — |
| ISO 7093 · M10 | 10.5 | 30 | 2.5 | — |
| ISO 7093 · M12 | 13 | 37 | 3 | — |
| ISO 7093 · M14 | 15 | 44 | 3 | — |
| ISO 7093 · M16 | 17 | 50 | 3 | — |
| ISO 7093 · M18 | 19 | 56 | 4 | — |
| ISO 7093 · M20 | 21 | 60 | 4 | — |
| ISO 7093 · M22 | 23 | 66 | 5 | — |
| ISO 7093 · M24 | 25 | 72 | 5 | — |
| ISO 7093 · M27 | 30 | 85 | 6 | — |
| ISO 7093 · M30 | 33 | 92 | 6 | — |
| ISO 7093 · M36 | 39 | 110 | 8 | — |
| DIN 9021 · M3 | 3.2 | 9 | 0.8 | — |
| DIN 9021 · M4 | 4.3 | 12 | 1 | — |
| DIN 9021 · M5 | 5.3 | 15 | 1.2 | — |
| DIN 9021 · M6 | 6.4 | 18 | 1.6 | — |
| DIN 9021 · M8 | 8.4 | 24 | 2 | — |
| DIN 9021 · M10 | 10.5 | 30 | 2.5 | — |
| DIN 9021 · M12 | 13 | 37 | 3 | — |
| DIN 9021 · M14 | 15 | 44 | 3 | — |
| DIN 9021 · M16 | 17 | 50 | 3 | — |
| DIN 9021 · M18 | 20 | 56 | 4 | — |
| DIN 9021 · M20 | 22 | 60 | 4 | — |
| DIN 9021 · M24 | 26 | 72 | 5 | — |
| DIN 9021 · M30 | 33 | 92 | 6 | — |
| DIN 9021 · M36 | 39 | 110 | 8 | — |
| DIN 127-B · M3 | 3.1 | 6.2 | 0.8 | 1.3 |
| DIN 127-B · M4 | 4.1 | 7.6 | 0.9 | 1.5 |
| DIN 127-B · M5 | 5.1 | 9.2 | 1.2 | 1.8 |
| DIN 127-B · M6 | 6.1 | 11.8 | 1.6 | 2.5 |
| DIN 127-B · M8 | 8.1 | 14.8 | 2 | 3 |
| DIN 127-B · M10 | 10.2 | 18.1 | 2.2 | 3.5 |
| DIN 127-B · M12 | 12.2 | 21.1 | 2.5 | 4 |
| DIN 127-B · M14 | 14.2 | 24.1 | 3 | 4.5 |
| DIN 127-B · M16 | 16.2 | 27.4 | 3.5 | 5 |
| DIN 127-B · M18 | 18.2 | 29.4 | 3.5 | 5 |
| DIN 127-B · M20 | 20.2 | 33.6 | 4 | 6 |
| DIN 127-B · M22 | 22.5 | 35.9 | 4 | 6 |
| DIN 127-B · M24 | 24.5 | 40 | 5 | 7 |
| DIN 127-B · M27 | 27.5 | 43 | 5 | 7 |
| DIN 127-B · M30 | 30.5 | 48.2 | 6 | 8 |
| DIN 127-B · M36 | 36.5 | 58.2 | 6 | 10 |
All dimensions nominal, in millimetres: d1 the smallest hole, d2 the largest outside diameter. A dash: the two sources differ (the thickness of ISO 7093 M5) or the column does not apply. Rows that only one source lists are left out: ISO 7093 M33, DIN 9021 M22, M27 and M33, DIN 127-B M33. Tolerances are not given.
Sources
Every value in the table is in two independent published tables, a washer maker’s or distributor’s data sheet and a published summary of the standard, and is left out where they differ. The hardness classes of ISO 7089 are from two summaries of the standard published by national standards bodies.
Before you send the request
Questions about washers in an RFQ
Plain or large washer: how do I tell them apart?
Measure the outside diameter d2 and set it against the bolt size. For the same bolt a large-series washer is much wider: an M12 washer to ISO 7089 is 24 mm across, one to ISO 7093 is 37 mm. The finder also matches a measured d1, d2 and thickness to the nearest row, within 0.5 mm on the diameters and 0.2 mm on the thickness.
Are DIN 125-A and ISO 7089, or DIN 9021 and ISO 7093, the same washer?
DIN 125 and DIN 9021 are withdrawn; ISO 7089 and ISO 7093 replaced them. In the tables this finder is built from, DIN 125-A and ISO 7089 have the same d1, d2 and thickness from M3 to M36. DIN 9021 and ISO 7093 differ at M18, M20 and M24, where the DIN 9021 hole is 1 mm larger: 20, 22 and 26 mm against 19, 21 and 25 mm. Give the standard of the old washer in the request.
Which hardness class does an ISO 7089 washer need?
ISO 7089 has two hardness classes. 200 HV is for bolts and screws up to property class 8.8 and nuts up to class 8; 300 HV is for bolts and screws up to 10.9 and nuts up to class 10. The size does not show the class: take it from the marking on the bolt head or from the last order, and state it in the request.
What about spring washers to DIN 127?
DIN 127 is withdrawn, but spring washers to DIN 127 form B, with flat ends, are still common in catalogues. Measure the inside and outside diameter and the thickness s of the section; the finder gives d1, d2, s and the width b of the section for form B. Form A, with bent ends, is not in this finder.
What should the request include?
The standard and the bolt size (ISO 7089 M12, DIN 127-B M20), the material and hardness class (steel 200 HV or 300 HV, stainless A2 or A4), the finish (plain, zinc or hot-dip galvanised), the quantity, and a photograph of the old washer beside a ruler.
Washer found?
Send the line with a photograph of the old washer.
A row of the standard is a cross-check of sizes, not a washer selection. Attach the photograph and your measurements, and Vessel Core checks them before an offer goes back.
Buyer tools
