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Serrated Lock Washer Dimensions (DIN 6798 A, J, V, M1.6 to M30)

Guide · Updated October 28, 2026

DIN 6798 covers serrated lock washers in form A (external teeth), J (internal teeth) and V (countersunk), M1.6 to M30. Forms A and J share one table: hole, OD and thickness agree across the fasteners.eu DIN 6798 A table, the Aspen Fasteners DIN 6798 spec and the Ferreteria Bonet DIN 6798 sheet; tolerances and form A tooth counts agree across fasteners.eu and Aspen. Form V d3 and s2 agree across Aspen and Bonet for M3 to M16. Skipped: J and V tooth counts and weights. Check your supplier for critical work.

Step by step

1. Pick the form: A has teeth on the outside edge, J on the inside edge, V is conical for 90 degree countersunk screws.
2. Pick the size: Choose by thread, M1.6 to M30 for A and J.
3. Read hole and OD: Forms A and J share the same hole d1, OD d2 and thickness s1.
4. Form V: Use d3 (approx. OD) and s2 thickness; only sizes with agreeing sources are filled in.
5. Check the head: Use J when the screw head is smaller than the washer OD; A for maximum grip.
6. Order it: Designate as Washer DIN 6798 A 8.4 (form and hole).

DIN 6798 serrated lock washer dimensions (mm)

Forms A and J: hole d1 min and max, OD d2 max and min, thickness s1, min teeth (form A). Form V: d3 approx. and s2.

• Thread | d1 | d1 max | d2 | d2 min | s1 | Teeth A | V d3 | V s2
• M1.6 | 1.7 | 1.84 | 3.6 | 3.3 | 0.3 | 9 | — | —
• M2 | 2.2 | 2.34 | 4.5 | 4.2 | 0.3 | 9 | — | —
• M2.5 | 2.7 | 2.84 | 5.5 | 5.2 | 0.4 | 9 | — | —
• M3 | 3.2 | 3.38 | 6 | 5.7 | 0.4 | 9 | 6 | 0.2
• M3.5 | 3.7 | 3.88 | 7 | 6.64 | 0.5 | 10 | — | —
• M4 | 4.3 | 4.48 | 8 | 7.64 | 0.5 | 11 | 8 | 0.25
• M5 | 5.3 | 5.48 | 10 | 9.64 | 0.6 | 11 | 9.8 | 0.3
• M6 | 6.4 | 6.62 | 11 | 10.57 | 0.7 | 12 | 11.8 | 0.4
• M7 | 7.4 | 7.62 | 12.5 | 12.07 | 0.8 | 14 | — | —
• M8 | 8.4 | 8.62 | 15 | 14.57 | 0.8 | 14 | 15.3 | 0.4
• M10 | 10.5 | 10.77 | 18 | 17.57 | 0.9 | 16 | 19 | 0.5
• M12 | 13 | 13.27 | 20.5 | 19.98 | 1 | 16 | 23 | 0.5
• M14 | 15 | 15.27 | 24 | 23.48 | 1 | 18 | — | —
• M16 | 17 | 17.27 | 26 | 25.48 | 1.2 | 18 | 30.2 | 0.6
• M18 | 19 | 19.33 | 30 | 29.48 | 1.4 | 18 | — | —
• M20 | 21 | 21.33 | 33 | 32.38 | 1.4 | 20 | — | —
• M22 | 23 | 23.33 | 36 | 35.38 | 1.5 | 20 | — | —
• M24 | 25 | 25.33 | 38 | 37.38 | 1.5 | 20 | — | —
• M27 | 28 | 28.33 | 44 | 43.38 | 1.6 | 22 | — | —
• M30 | 31 | 31.39 | 48 | 47.38 | 1.6 | 22 | — | —

Worked example: M6 screw

An M6 DIN 6798 A or J washer has a 6.4 mm hole, 11 mm OD and is 0.7 mm thick. For an M6 countersunk screw, form V is about 11.8 mm across and 0.4 mm thick.

Common problems

• Teeth flattened: washer reused; replace it.
• Paint damage: teeth bite the surface by design; use J under small heads.
• Countersunk screw sits proud: use form V, not A.

FAQ

What is DIN 6798?

A serrated (toothed) lock washer: form A external teeth, form J internal teeth, form V conical for countersunk screws.

Do A and J share dimensions?

Yes. The sources give one hole, OD and thickness table for both forms.

Why are some form V cells blank?

Form V values are shown only where two sources agree; M2, M2.5 and M14 lacked a second source, and V is not made above M16.

What was skipped?

Tooth counts for forms J and V (only one source), and weights.

Do serrated washers stop loosening?

They help on light-duty screws, but for preloaded joints prefer proper preload or a tested locking method.

Related guides and calculators

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• Curved spring washers (DIN 128 A)
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• Spring lock washers (DIN 127 B)
• Large OD washer dimensions (DIN 9021)
• Flat washer size chart (SAE, USS, metric)
• Heavy-duty washer dimensions (DIN 7989)
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General shop information only — follow your drawing, tool maker's data and your quality system.