DIN 981 Locknuts (KM Series, Bearing Mounting)
DIN 981 locknuts, threads M10x0,75–M140x2 (KM0–KM28) — the knurled-slot round locknut that clamps a bearing inner ring or a tapered adaptor sleeve, with the collected ring/hub/slot ladder including the light (KML) series the source interleaves.
Last updated: 2026-11
Specifications
A DIN 981 locknut is the knurled-edged round nut that does the final clamp in bearing mounting: it screws onto the threaded adaptor sleeve (or the shaft thread) and presses the bearing inner ring up the taper, setting the clearance; its slots take the locking tab or the bent washer, and its knurled outside gives a hook spanner the grip. The collected table is the KM designation ladder — marking KM0 at M10x0,75 stepping to KM27 at M135x2, in fine-pitch threads throughout — and carries per size: the ring outside diameter d2 (n13, 18 mm at KM0 growing to 175 mm), the hub diameter d3 (h13), the ring thickness h, the slot width b (JS14, 3 → 14 mm) and depth t (H17, 2 → 6 mm), the tab dimension z as printed, and the weight per piece. From KM24 upward the source interleaves a light series (markings KML24, KML26, KML28): same thread, smaller d2/d3 ring — both rows are reproduced in printed order, and the capture ends at KML28 without the heavy KM28 row (flagged under the table). Assembly reading: thread the nut onto the adaptor until the bearing seats, check the inner ring is square, then lock through the slots — the slot width b is what the tab washer tongue engages. Load and material data are not tabulated — per RFQ.
| Standard | DIN 981 — locknuts for bearing/adaptor sleeve mounting (KM series, knurled round nut with locking slots) |
|---|---|
| Thread range | M10x0,75 – M140x2, fine pitch throughout; thirty-three rows in the collected table incl. light-series KML rows |
| KM designations | Marking ladder KM0 (M10x0,75) → KM27 (M135x2); capture ends at KML28 (M140x2 light) — heavy KM28 not returned (see table note) |
| Ring geometry | d2 (n13) 18 → 175 mm; d3 (h13) 13,5 → 160 mm; thickness h 4 → 22 mm |
| Slots | Width b (JS14) 3 → 14 mm — engages the tab-lock washer; depth t (H17) 2 → 6 mm; tab dimension z 0,04–0,06 as printed |
| Light series | KML24/26/28 rows (M120x2, M130x2, M140x2) carry smaller d2/d3/weight than the adjacent KM rows — the light series, reproduced in printed order |
| Materials / finishes | Not tabulated by the collected specification — per RFQ (state material, finish and the mating adaptor sleeve at quotation) |
| Thread (d1) | Ring OD (d2 n13) | Hub Dia. (d3 h13) | Thickness (h h13) | Slot Width (b JS14) | Slot Depth (t H17) | z | Weight kg/pc | Marking |
|---|---|---|---|---|---|---|---|---|
| M10x0,75 | 18 | 13,5 | 4 | 3 | 2 | 0,04 | 0,004 | KM0 |
| M12x1 | 22 | 17 | 4 | 3 | 2 | 0,04 | 0,007 | KM1 |
| M15x1 | 25 | 21 | 5 | 4 | 2 | 0,04 | 0,01 | KM2 |
| M17x1 | 28 | 24 | 5 | 4 | 2 | 0,04 | 0,013 | KM3 |
| M20x1 | 32 | 26 | 6 | 4 | 2 | 0,04 | 0,019 | KM4 |
| M24x1,5 | 38 | 32 | 7 | 5 | 2 | 0,04 | 0,025 | KM5 |
| M30x1,5 | 45 | 38 | 7 | 5 | 2 | 0,04 | 0,043 | KM6 |
| M35x1,5 | 52 | 44 | 8 | 5 | 2 | 0,04 | 0,053 | KM7 |
| M40x1,5 | 58 | 50 | 9 | 6 | 2,5 | 0,04 | 0,085 | KM8 |
| M45x1,5 | 65 | 56 | 10 | 6 | 2,5 | 0,04 | 0,119 | KM9 |
| M50x1,5 | 70 | 61 | 11 | 6 | 2,5 | 0,04 | 0,148 | KM10 |
| M55x2 | 75 | 67 | 11 | 7 | 3 | 0,05 | 0,158 | KM11 |
| M60x2 | 80 | 73 | 11 | 7 | 3 | 0,05 | 0,174 | KM12 |
| M65x2 | 85 | 79 | 12 | 7 | 3 | 0,05 | 0,203 | KM13 |
| M70x2 | 92 | 85 | 12 | 8 | 3,5 | 0,05 | 0,242 | KM14 |
| M75x2 | 98 | 90 | 13 | 8 | 3,5 | 0,05 | 0,287 | KM15 |
| M80x2 | 105 | 95 | 15 | 8 | 3,5 | 0,05 | 0,397 | KM16 |
| M85x2 | 110 | 102 | 16 | 8 | 3,5 | 0,05 | 0,451 | KM17 |
| M90x2 | 120 | 108 | 16 | 10 | 4 | 0,05 | 0,556 | KM18 |
| M95x2 | 125 | 113 | 17 | 10 | 4 | 0,05 | 0,658 | KM19 |
| M100x2 | 130 | 120 | 18 | 10 | 4 | 0,05 | 0,698 | KM20 |
| M105x2 | 140 | 126 | 18 | 12 | 5 | 0,05 | 0,845 | KM21 |
| M110x2 | 145 | 133 | 19 | 12 | 5 | 0,05 | 0,965 | KM22 |
| M115x2 | 150 | 137 | 19 | 12 | 5 | 0,05 | 1,01 | KM23 |
| M120x2 | 145 | 135 | 20 | 12 | 5 | 0,05 | 0,78 | KML24 |
| M120x2 | 155 | 138 | 20 | 12 | 5 | 0,05 | 1,08 | KM24 |
| M125x2 | 160 | 148 | 21 | 12 | 5 | 0,05 | 1,19 | KM25 |
| M130x2 | 155 | 145 | 21 | 12 | 5 | 0,06 | 0,88 | KML26 |
| M130x2 | 165 | 149 | 21 | 12 | 5 | 0,06 | 1,25 | KM26 |
| M135x2 | 175 | 160 | 22 | 14 | 6 | 0,06 | 1,55 | KM27 |
| M140x2 | 165 | 155 | 22 | 12 | 5 | 0,06 | 0,99 | KML28 |
- Row 31 (M140x2): The capture ends at the KML28 (M140x2 light-series) row; the heavy KM28 row for M140x2 is not present in the published table. Verify against the standard before quoting M140x2 heavy series.
- KML rows carry a smaller d2/d3/weight than the adjacent same-thread KM rows — the light series the source interleaves; both reproduced verbatim in printed order.
Materials
- Material and finish specified per RFQ — bearing locknuts clamp precision bores; state the shaft/adaptor thread, the tab washer pairing and the environment with the order
Ordering & documentation
Documents
Shipments are backed by Mill Test Certificate (MTC), Dimensional Report, Salt Spray Test Report on request, with full batch traceability from raw material to finished product. Quality management follows the owner-confirmed compliance list: ISO 9001:2015, RoHS, REACH. Exact document sets are confirmed on the order.
Quotation
- The fastener family (DIN 981 Locknuts (KM Series, Bearing Mounting)) plus the standard designation from your drawing — DIN / ISO / JIS / ASTM / ANSI, or a drawing for custom parts.
- Size (diameter and length), thread type (metric or inch), property class or grade, and coating or finish.
- Quantity per size and your target delivery date.
- Destination country, and any required documents (for example a mill test certificate) so the quote includes them.
Sample & supply
Minimum order quantity is 10,000 pieces. Stock items run 3–7 days. Quantities or variants outside the standard range are confirmed at quotation.
Storage & shipping
Parts are packed for export and shipped factory-direct to buyers in Europe, Asia, the Americas and the Middle East. Store fasteners dry and protected until installation, and keep coated parts in their packaging until use; specific packing and preservation requirements can be stated on the order and confirmed at quotation.
Frequently asked questions
How do I pick the DIN 981 locknut for a bearing mounting, and what changes above M115?
The thread picks the nut: a DIN 981 locknut always matches the threaded adaptor sleeve or shaft end it clamps — the KM marking (KM0 through KM27 in the collected ladder) is the shorthand the bearing trade uses, so an adaptor specified as "KM4" takes the M20x1 nut marked KM4. Off the collected table, check three things: the slot width b (3 mm at KM0 up to 14 mm at KM27) against your tab-lock washer tongue, the ring outside diameter d2 (18 mm up to 175 mm) against the housing shoulder clearance, and the thickness h (4 → 22 mm) against the shaft end protrusion. Above M115 the picture splits: the source interleaves a light series — KML24, KML26 and KML28 at M120x2, M130x2 and M140x2 — with smaller ring diameters (d2 145/155/165 mm against the heavy 155/165/…) and lighter weight, and the capture ends at KML28 without a heavy KM28 row (flagged under the table), so the M140x2 heavy series is not covered by published tables — quote it explicitly and it will be confirmed at RFQ. Assembly order: seat the bearing on the sleeve with the nut, verify the inner ring runs square, then bend the tab into a slot. Materials, finishes and clamping-load data are RFQ lines — the collected table carries geometry and weight only.
Request a Quote
Get factory-direct pricing from the manufacturer.
What to include in your inquiry
- ✓ Standard and property class (e.g. DIN 912, ISO 4762, class 8.8) — or a drawing for custom parts.
- ✓ Sizes, lengths and thread type (metric or inch).
- ✓ Quantity per size and your target delivery date.
- ✓ Destination country, plus any coating or finish requirement.
- ✓ Any documents you need with the shipment (e.g. mill test certificate) so the quote includes them.
- ✓ Your inquiry goes straight to the factory team by email and gets a reply within 24 hours.
- ✓ Factory-direct pricing
- ✓ Standard and custom specifications
- ✓ Factory-direct export to buyers in Europe, Asia, the Americas and the Middle East
- ✓ Full fastener family support