# Bearing locknuts KM, DIN 981 / ISO 2982-2: KM0–KM10 (M10×0.75–M50×1.5) outside diameter, width, slots

> What are the KM locknut (DIN 981) dimensions, from KM0 M10×0.75 to KM10 M50×1.5?

- Category: Hardware › Bearings, rails & motion
- Kind: Standard part
- Basis: Schaeffler and NTN catalogue pages for KM0, KM1, KM2 (main dimensions to DIN 981), Kramp and FAG listings for KM10, KM12, KM15, KM23, and SKF KM series values for the remaining sizes
- Page: https://xemstudio.com/objects/bearing-locknuts-km-din-981/ · JSON: https://xemstudio.com/api/geometry?object=bearing-locknuts-km-din-981 · Plain text: https://xemstudio.com/objects/bearing-locknuts-km-din-981/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
- Use in every chat: add https://xemstudio.com/mcp as a connector (https://xemstudio.com/use-with-ai/)

**Exact dimensions.** Every file is drawn at true size with no tolerance added. The holes and pins that meet another part are listed below under Mating features, with the fit each joint needs; open those by your process's clearance before making the part.

## Notes

- Columns: designation, thread G, outside d2, chamfer diameter d1, width B, slot width b, slot depth h. Four slots, 30° chamfer on one face (Schaeffler). Use with MB lock washers (DIN 5406).
- Verified on the maker pages read: KM0 (d2 18, d1 13.5, B 4, b 3), KM1 (22, 17, 4, 3, h 2), KM2 (25, 21, 5, 4, h 2), KM10 (70 × 11). KM3–KM9 are SKF catalogue values; check a maker drawing before relying on d1 or h for those.
- Files: thread as a plain bore at the major diameter, as for the other nuts on Xem.

## Mating features (exact size; open press / slide / run / socket by your process clearance, leave designed and clamp as drawn)

| feature | exact | mates with | fit | files |
|---|---|---|---|---|
| thread (plain bore at the major Ø) | G: M10×0.75 (KM0) to M50×1.5 (KM10) | shaft thread of the same G; seats against the bearing inner ring or a spacer | designed | all |
| 4 slots on the outside | b wide × h deep (KM0 3 × 2, KM10 10 × 3) | hook spanner, and the outer tab of an MB lock washer (DIN 5406, same number) bent into one slot | designed | all |

## Sizes

| size | thread | d2 | d1 | B | b | h |
|---|---|---|---|---|---|---|
| KM0 | M10x0.75 | 18 | 13.5 | 4 | 3 | 2 |
| KM1 | M12x1 | 22 | 17 | 4 | 3 | 2 |
| KM2 | M15x1 | 25 | 21 | 5 | 4 | 2 |
| KM3 | M17x1 | 28 | 24 | 5 | 4 | 2 |
| KM4 | M20x1 | 32 | 26 | 6 | 4 | 2 |
| KM5 | M25x1.5 | 38 | 32 | 7 | 5 | 2 |
| KM6 | M30x1.5 | 45 | 38 | 7 | 5 | 2 |
| KM7 | M35x1.5 | 52 | 44 | 8 | 5 | 2 |
| KM8 | M40x1.5 | 58 | 50 | 9 | 6 | 2.5 |
| KM9 | M45x1.5 | 65 | 56 | 10 | 6 | 2.5 |
| KM10 | M50x1.5 | 70 | 61 | 11 | 6 | 2.5 |

## Where the files are

- Schaeffler: [KM0 locknut, main dimensions to DIN 981: G, d2, B, d1, b](https://medias-at.schaeffler.com/en/produit/rotary/roulements-et-paliers-lisses/accessoires/ecrou-a-encoches/km0/p/418251) — web — Publisher's page; dimensions are facts
- Schaeffler: [KM2 locknut, main dimensions to DIN 981](https://medias.schaeffler.com/medias/en!hp.ec.br.pr/KM*KM2) — web — Publisher's page; dimensions are facts
- Acorn Industrial: [KM 9 locknut: M45×1.5, 65 mm OD, 10 mm wide](https://acorn-ind.co.uk/p/km9-fag) — web — Publisher's page; dimensions are facts

## Free STEP/STL (11 parts, CC BY 4.0, Xem Studio)

Index: https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/index.json

- km0: [STEP](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km0.step) · [STL](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km0.stl) — KM0 M10x0.75: Ø18 × 4, 4 slots 3×2, thread as Ø10 bore
- km1: [STEP](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km1.step) · [STL](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km1.stl) — KM1 M12x1: Ø22 × 4, 4 slots 3×2, thread as Ø12 bore
- km2: [STEP](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km2.step) · [STL](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km2.stl) — KM2 M15x1: Ø25 × 5, 4 slots 4×2, thread as Ø15 bore
- km3: [STEP](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km3.step) · [STL](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km3.stl) — KM3 M17x1: Ø28 × 5, 4 slots 4×2, thread as Ø17 bore
- km4: [STEP](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km4.step) · [STL](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km4.stl) — KM4 M20x1: Ø32 × 6, 4 slots 4×2, thread as Ø20 bore
- km5: [STEP](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km5.step) · [STL](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km5.stl) — KM5 M25x1.5: Ø38 × 7, 4 slots 5×2, thread as Ø25 bore
- km6: [STEP](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km6.step) · [STL](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km6.stl) — KM6 M30x1.5: Ø45 × 7, 4 slots 5×2, thread as Ø30 bore
- km7: [STEP](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km7.step) · [STL](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km7.stl) — KM7 M35x1.5: Ø52 × 8, 4 slots 5×2, thread as Ø35 bore
- km8: [STEP](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km8.step) · [STL](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km8.stl) — KM8 M40x1.5: Ø58 × 9, 4 slots 6×2.5, thread as Ø40 bore
- km9: [STEP](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km9.step) · [STL](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km9.stl) — KM9 M45x1.5: Ø65 × 10, 4 slots 6×2.5, thread as Ø45 bore
- km10: [STEP](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km10.step) · [STL](https://xemstudio.com/files/hardware/bearing-locknuts-km-din-981/km10.stl) — KM10 M50x1.5: Ø70 × 11, 4 slots 6×2.5, thread as Ø50 bore

## Questions

**What thread is a KM0 locknut?**

M10 × 0.75, 18 mm outside diameter, 4 mm wide, four 3 × 2 mm slots (DIN 981).

**What locks a KM nut?**

An MB tab washer to DIN 5406 of the same number (MB0 for KM0) bends into one of the four slots.

## Fits with

- [608 ball bearing](https://xemstudio.com/objects/608-bearing/)
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- [Retaining rings DIN 471 (external, for shafts): ring dimensions and groove diameter d2 × width m, 3 to 100 mm](https://xemstudio.com/objects/retaining-rings-din-471-external/)