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Pin Spanner Sizes (DIN 1810 Form B, 12 to 220 mm)
Guide · Updated October 28, 2026
DIN 1810 form B covers pin spanners (hook spanners with a round pin) for round nuts with side pin holes such as DIN 1816. Size range and pin diameter agree across the Spaenaur DIN 1810 B catalog page, the Newman Tools DIN 1810B table and the McMaster-Carr DIN 1810B listing for 16-18 and 25-28 to 155-165, and across Spaenaur and Newman for 12-14, 20-22, 180-195 and 205-220. Handle length agrees between Spaenaur and Newman (McMaster lists inch lengths within 2 mm) except 45-50 and 52-55, where they say 205 and 206 mm. Skipped: thickness (one clean source only) and 230-245 and 260-270 (one source only).
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Step by step
- Measure the nut: Measure the outside diameter of the round nut, or read d2 from the DIN 1816 chart.
- Find the range: Pick the DIN 1810 form B size whose range covers that diameter, for example 25-28 for a 28 mm nut.
- Check the pin: The spanner pin must match the nut pin hole: a 25-28 spanner has a 3 mm pin for the 3 mm holes on DIN 1816 M10x1 and M12x1.5 nuts.
- Seat the pin: Push the pin fully into a side hole with the hook arc lying flat on the nut.
- Pull the right way: Pull so the hook wraps onto the nut; pulling the other way lifts the pin out.
- Do not overload the pin: Small pins (2 to 2.5 mm) shear easily; no cheater bars on the small sizes.
DIN 1810 form B pin spanner sizes (mm)
Columns: size (nut outside diameter range), pin diameter d, overall length L, DIN 1816 nuts it fits. *Sources differ by 1 mm.
- Size | Pin d | L | DIN 1816 nuts
- DIN 1810-B12-14 | 2 | 110 | -
- DIN 1810-B16-18 | 2.5 | 110 | M6x0.75
- DIN 1810-B20-22 | 2.5 | 110 | M8x1
- DIN 1810-B25-28 | 3 | 136 | M10x1, M12x1.5
- DIN 1810-B30-32 | 4 | 136 | M14x1.5, M16x1.5
- DIN 1810-B34-36 | 4 | 170 | M18x1.5, M20x1.5
- DIN 1810-B40-42 | 4 | 170 | M22x1.5
- DIN 1810-B45-50 | 5 | 205-206* | -
- DIN 1810-B52-55 | 5 | 205-206* | -
- DIN 1810-B58-62 | 5 | 240 | -
- DIN 1810-B68-75 | 6 | 240 | -
- DIN 1810-B80-90 | 6 | 280 | -
- DIN 1810-B95-100 | 8 | 280 | -
- DIN 1810-B110-115 | 8 | 335 | -
- DIN 1810-B120-130 | 8 | 335 | -
- DIN 1810-B135-145 | 8 | 380 | -
- DIN 1810-B155-165 | 8 | 380 | -
- DIN 1810-B180-195 | 10 | 470 | -
- DIN 1810-B205-220 | 10 | 470 | -
Worked example: M12x1.5 pin-hole nut
A DIN 1816 M12x1.5 nut is 28 mm across with 3 mm pin holes, so it takes the DIN 1810-B25-28 spanner: 3 mm pin, 136 mm long. The same spanner fits the 25 mm M10x1 nut, which also has 3 mm holes.
Pin spanner vs hook vs face spanner
- Form B pin: one round pin for a side hole (DIN 1816).
- Form A hook: square nose for outside slots (DIN 1804, DIN 981).
- Face spanner: two pins for holes on the end face.
Common problems
- Pin bends or shears: spanner too small for the load, or pin not fully seated.
- Spanner rocks: pin smaller than the hole; check the DIN 1816 d4 value.
- Hole edges burring: pulling the open way. Pull so the hook wraps the nut.
FAQ
What is a DIN 1810 form B spanner?
A hook spanner with a round pin at the tip instead of a square nose. The pin drops into a radial hole on the side of a round nut, collar or bearing ring.
Form A or form B?
Form A has a square nose for slotted nuts (DIN 1804, DIN 981). Form B has a round pin for nuts with side pin holes (DIN 1816). They share the same size ranges and handle lengths.
Does the pin size matter?
Yes. A pin smaller than the hole lets the spanner rock and burr the hole; a bigger pin will not go in. On DIN 1816 nuts the hole d4 matches the spanner pin.
Why does 45-50 say 205-206?
Spaenaur lists 205 mm and Newman Tools lists 206 mm for 45-50 and 52-55. Pin diameter agrees, so we kept the rows and flagged the length.
Why stop at 205-220?
Only one of our sources lists 230-245 and 260-270, so those rows are left off until a second source confirms them.
Is this a face pin spanner?
No. Face spanners (DIN 3116) have two pins that go into holes on the end face. Form B has one pin for a hole on the side.
Related guides and calculators
- Hook spanner sizes (DIN 1810 Form A)
- Round nut with pin holes (DIN 1816)
- Slotted round nut dimensions (DIN 1804)
- All free machinist calculators
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