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Slotted Round Nut Dimensions (DIN 1804, M8 to M60)
Guide · Updated October 28, 2026
DIN 1804 covers slotted round nuts for hook spanners, in ISO metric fine thread. Outside diameter d2, face diameter d3, slot width b, height h and slot count below agree across the LB Fertigungstechnik DIN 1804 data sheet, the Ferrobend (din-fasteners.com) DIN 1804 table and the Elesa+Ganter DIN 1804 catalog page. Slot depth t agrees across LB, Ferrobend and the Wasi DIN 1804 sheet (M8 and M10 in two of them). Hook spanner sizes are from Elesa+Ganter. Skipped: M6x0.75 (only two sources) and M62x1.5 and up (thin coverage, one typo). Tolerances: d2 h11, h h14, thread 4H; raised face z is 0.5 mm. Check the current edition or your supplier for critical work.
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Step by step
- Measure the thread: Measure the shaft thread major diameter and pitch; DIN 1804 uses ISO metric fine thread such as M20x1.5 or M40x1.5.
- Pick the nut row: Find the thread in the chart to get outside diameter d2, height h and the slot count.
- Check the space: Make sure d2 and h clear the bearing, pulley or housing face, and that the raised face d3 bears on the part.
- Pick the hook spanner: Use the DIN 1810 form A hook spanner listed for that row; its range must cover d2.
- Tighten in a slot: Seat the spanner hook fully in a slot (width b, depth t) and tighten; move slots as you go.
- Lock it: Lock with a tab washer, a second nut, a set screw or thread locker, since a plain slotted nut can back off.
DIN 1804 slotted round nut dimensions (mm)
Columns: thread d, outside diameter d2, face diameter d3, slot width b, height h, slot depth t, number of slots, DIN 1810 hook spanner.
- Thread d | d2 | d3 | b | h | t | Slots | Spanner
- M8x1 | 20 | 16 | 4 | 5 | 1.5 | 4 | DIN 1810-A16-20
- M10x1 | 25 | 20 | 5 | 6 | 2 | 4 | DIN 1810-A25-28
- M12x1.5 | 28 | 23 | 5 | 6 | 2 | 4 | DIN 1810-A25-28
- M14x1.5 | 30 | 25 | 5 | 7 | 2 | 4 | DIN 1810-A30-32
- M16x1.5 | 32 | 27 | 5 | 7 | 2 | 4 | DIN 1810-A30-32
- M18x1.5 | 34 | 28 | 6 | 8 | 2.5 | 4 | DIN 1810-A34-36
- M20x1.5 | 36 | 30 | 6 | 8 | 2.5 | 4 | DIN 1810-A34-36
- M22x1.5 | 40 | 34 | 6 | 9 | 2.5 | 4 | DIN 1810-A40-42
- M24x1.5 | 42 | 36 | 6 | 9 | 2.5 | 4 | DIN 1810-A40-42
- M26x1.5 | 45 | 38 | 7 | 10 | 3 | 4 | DIN 1810-A45-50
- M28x1.5 | 50 | 43 | 7 | 10 | 3 | 4 | DIN 1810-A45-50
- M30x1.5 | 50 | 43 | 7 | 10 | 3 | 4 | DIN 1810-A45-50
- M32x1.5 | 52 | 45 | 7 | 11 | 3 | 4 | DIN 1810-A52-55
- M35x1.5 | 55 | 48 | 7 | 11 | 3 | 4 | DIN 1810-A52-55
- M38x1.5 | 58 | 50 | 8 | 11 | 3.5 | 4 | DIN 1810-A58-62
- M40x1.5 | 62 | 54 | 8 | 12 | 3.5 | 4 | DIN 1810-A58-62
- M42x1.5 | 62 | 54 | 8 | 12 | 3.5 | 4 | DIN 1810-A58-62
- M45x1.5 | 68 | 60 | 8 | 12 | 3.5 | 6 | DIN 1810-A68-75
- M48x1.5 | 75 | 67 | 8 | 13 | 3.5 | 6 | DIN 1810-A68-75
- M50x1.5 | 75 | 67 | 8 | 13 | 3.5 | 6 | DIN 1810-A68-75
- M52x1.5 | 80 | 70 | 10 | 13 | 4 | 6 | DIN 1810-A80-90
- M55x1.5 | 80 | 70 | 10 | 13 | 4 | 6 | DIN 1810-A80-90
- M58x1.5 | 90 | 80 | 10 | 13 | 4 | 6 | DIN 1810-A80-90
- M60x1.5 | 90 | 80 | 10 | 13 | 4 | 6 | DIN 1810-A80-90
Worked example: M30x1.5 shaft
A M30x1.5 shaft end takes a DIN 1804 M30x1.5 nut: 50 mm across, 10 mm tall, four slots 7 mm wide and 3 mm deep. Leave about 51 mm of clear diameter and 10 mm of thread past the part, and use a DIN 1810 A45-50 hook spanner.
Slots vs pin holes vs hex
- Slots (DIN 1804): hook spanner, quick to engage, common on shafts and bearings.
- Pin holes (DIN 1816): smooth outside, needs a pin spanner.
- Hex: standard wrench, but needs more radial room.
Common problems
- Wrong spanner range: the hook rides out and chews the slot; match the DIN 1810 size.
- Nut loosening: add a locking method.
- Coarse thread bought by mistake: DIN 1804 is fine thread only.
FAQ
What is a DIN 1804 nut?
A round steel nut with slots cut across its outside diameter, turned with a hook (C) spanner. It is low and compact, so it fits on shafts and spindles where a hex will not.
How many slots does a DIN 1804 nut have?
Four slots up to M42x1.5, six from M45x1.5 to M120x2 and eight from M125x2 up, per our sources.
Which hook spanner fits?
DIN 1810 form A hook spanners are sized by outside diameter range, for example A34-36 for the M18 and M20 nuts (36 mm and 34 mm across).
How is DIN 1804 different from DIN 1816 and DIN 981?
DIN 1816 nuts have round pin holes in the side for a pin spanner. DIN 981 (KM) are bearing lock nuts with their own size series. DIN 1804 uses outside slots for a hook spanner.
What do d3 and z mean?
d3 is the raised face diameter that bears on the part and z is its height (0.5 mm on these sizes). Put the d3 side against the part.
Why stop at M60?
Our three sources agree on every value from M8 to M60. Past that, coverage thins and one table has a typo, so we left those rows off. The standard runs to M200x3.
Related guides and calculators
- Pin spanner sizes (DIN 1810 Form B)
- Hook spanner sizes (DIN 1810)
- Round nut with pin holes dimensions (DIN 1816)
- Hex nut with collar dimensions (DIN 6331)
- Hex castle nut dimensions (DIN 935)
- Square nut dimensions (DIN 557)
- Metric jam nut size chart (ISO 4035)
- Wrench size chart for bolts and nuts
- All free machinist calculators
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