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Tooth Lock Washer Dimensions (DIN 6797 Form A and J, M2 to M27)
Guide · Updated October 28, 2026
DIN 6797 covers toothed lock washers, form A (external teeth) and form J (internal teeth), M2 to M27. Hole, OD and thickness agree across the Aspen Fasteners DIN 6797 spec, the Ferreteria Bonet DIN 6797 sheet and the Lederer DIN 6797 catalog page (M3.5 and M7 rest on two). Skipped: form V, tolerances, tooth counts and weights. Check your supplier for critical work.
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Step by step
- Pick the form: A has teeth on the outside edge, J on the inside edge.
- Pick the size: Choose by thread, M2 to M27.
- Read the hole: Hole d1 is the nominal minimum.
- Read the OD: OD d2 is the nominal maximum; A and J share the same size.
- Check thickness: Thickness s of the steel strip.
- Order it: Designate as Toothed lock washer DIN 6797 A 8.4.
DIN 6797 tooth lock washer dimensions (mm)
Forms A and J. Columns: thread, hole d1, OD d2, thickness s.
- Thread | d1 | d2 | s
- M2 | 2.2 | 4.5 | 0.3
- M2.3 | 2.5 | 5 | 0.4
- M2.5 | 2.7 | 5.5 | 0.4
- M3 | 3.2 | 6 | 0.4
- M3.5 | — | 7 | 0.5
- M4 | 4.3 | 8 | 0.5
- M5 | 5.3 | 10 | 0.6
- M6 | 6.4 | 11 | 0.7
- M7 | 7.4 | 12.5 | 0.8
- M8 | 8.4 | 15 | 0.8
- M10 | 10.5 | 18 | 0.9
- M12 | 13 | 20.5 | 1
- M14 | 15 | 24 | 1
- M16 | 17 | 26 | 1.2
- M18 | 19 | 30 | 1.4
- M20 | 21 | 33 | 1.4
- M24 | 25 | 38 | 1.5
- M27 | 28 | 44 | 1.6
Worked example: M5 screw
An M5 DIN 6797 washer has a 5.3 mm hole, 10 mm OD and is 0.6 mm thick. Use form J under a small pan head, form A under a hex head.
Common problems
- Teeth flattened: washer reused; replace it.
- Teeth outside the head: use form J.
- Electrical contact needed: teeth through paint help, but keep away from coated finishes you must protect.
FAQ
What is DIN 6797?
A toothed lock washer with twisted teeth: form A external, form J internal. DIN 6798 is the serrated version with finer, more numerous teeth.
Is DIN 6797 still current?
One supplier catalog (Lederer) states DIN 6797 was withdrawn without replacement but the parts are still available. Check with your supplier.
Why no form V?
Countersunk form V values came from only one source, so they are not charted.
What was skipped?
Tolerances and tooth counts (only one source), form V, M3.5 hole and sizes M22 and M30, which lacked a second source.
DIN 6797 or DIN 6798?
Same hole, OD and thickness in the sources checked; 6797 has fewer, twisted teeth, 6798 more, serrated teeth.
Related guides and calculators
- Wave spring washers (DIN 137 B)
- Conical spring washers (DIN 6796)
- Curved spring washers (DIN 128 A)
- Serrated lock washer dimensions (DIN 6798)
- Spring lock washer dimensions (DIN 127 B)
- Large OD washer dimensions (DIN 9021)
- Flat washer size chart (SAE, USS, metric)
- All free machinist calculators
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