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Thick Washer Dimensions (DIN 7349, M3 to M30)
Guide · Updated October 28, 2026
DIN 7349 covers thick flat washers for bolts used with heavy spring pins (DIN 1481), M3 to M30. Hole, OD and thickness agree across the fasteners.eu DIN 7349 table (Ferrobolt shows the same table and was not counted), the BQF DIN 7349 page and the BOLTS open parts library table; M18 and M27 rest on fasteners.eu and BOLTS. The Aspen sheet was also checked. Conflicting cells are shown as a dash. Check your supplier for critical work.
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Step by step
- Pick the size: Choose by thread, M3 to M30.
- Read the hole: d1 is the washer hole.
- Read the OD: d2 is the outside diameter.
- Read the thickness: s is the washer thickness.
- Match the pin: The last column is the DIN 1481 heavy spring pin (slotted sleeve) size the washer is meant for.
- Order it: Designate as Washer DIN 7349 - 8.4 - St.
DIN 7349 thick washer dimensions (mm)
Columns: thread, hole d1, OD d2, thickness s, DIN 1481 spring pin size.
- Thread | d1 | d2 | s | DIN 1481 pin
- M3 | 3.2 | 9 | 1 | 6
- M4 | 4.3 | 12 | — | 8
- M5 | 5.3 | 15 | 2 | 10
- M6 | 6.4 | 17 | 3 | 12
- M8 | 8.4 | 21 | 4 | 16
- M10 | — | 25 | 4 | 18
- M12 | 13 | 30 | 6 | 21
- M14 | 15 | 36 | 6 | 25
- M16 | 17 | 40 | 6 | 28
- M18 | 19 | 44 | 8 | —
- M20 | 21 | 44 | 8 | 35
- M22 | 23 | 50 | 8 | 38
- M24 | 25 | 50 | 10 | 40
- M27 | 28 | 60 | 10 | —
- M30 | 31 | 68 | 10 | 50
Worked example: M8 bolt
An M8 DIN 7349 washer has an 8.4 mm hole, 21 mm OD and is 4 mm thick, sized for a 16 mm DIN 1481 heavy spring pin.
Common problems
- Washer too thin for the sleeve end: use DIN 7349, not DIN 125.
- Will not fit a counterbore: check d2.
- Wrong pin match: check the DIN 1481 column.
FAQ
What is DIN 7349?
A thick flat washer for bolts that pass through heavy spring pins (DIN 1481 clamping sleeves); the large, thick face bears on the sleeve end.
DIN 7349 vs DIN 7989?
Both are thick; DIN 7989 is 8 mm thick for structural bolts M10 to M30, while DIN 7349 thickness grows with size, 1 to 10 mm.
Why is the M4 thickness blank?
Sources disagree: 1.6 mm in fasteners.eu, BQF and the BOLTS library; 2 mm in the Aspen sheet.
Why is the M10 hole blank?
Sources disagree: 10.5 mm in fasteners.eu, BQF and BOLTS; 11 mm in the Aspen sheet.
Why are some pin sizes blank?
M18 and M27 pin sizes appeared in only one independent source.
What was skipped?
Weights, tolerances, the M4 thickness, the M10 hole and M18/M27 pin sizes.
Related guides and calculators
- Extra large washers (ISO 7094)
- Shim rings (DIN 988)
- Clevis pin washers (ISO 8738 / DIN 1440)
- Heavy-duty washer dimensions (DIN 7989)
- Large OD washer dimensions (DIN 9021)
- Spring lock washer dimensions (DIN 127 B)
- Conical spring washer dimensions (DIN 6796)
- Flat washer size chart (SAE, USS, metric)
- All free machinist calculators
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