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Hex Socket Screw Plug Dimensions (DIN 908, M10x1 to M64x2, G1/8 to G2)
Guide · Updated October 28, 2026
DIN 908 covers hexagon socket screw plugs with collar and parallel thread, from M10x1 to M64x2 and G1/8 to G2. Values agree across fasteners.eu, fasten.it, Ferretería Bonet and Elesa. Check your supplier for critical work.
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Step by step
- Identify the thread: DIN 908 comes in metric fine (DIN 13) and G pipe thread (ISO 228-1); check pitch before ordering.
- Check the port depth: The port needs at least i of full thread plus room for the collar to seat.
- Pick the key: Use a hex key of size s; it must reach the socket depth t.
- Seal it: The collar seals with a DIN 7603 ring or a bonded seal; the thread itself does not seal.
DIN 908 screw plug dimensions (mm)
Columns: thread d1 (metric fine and/or G), collar diameter d2, collar height c, thread length i, overall length l (approx.), hex socket s, socket across corners e min, socket depth t min.
- Size | d2 | c | i | l | s | e | t
- M10x1 / G1/8 | 14 | 3 | 8 | 11 | 5 | 5.7 | 5
- M12x1.5 | 17 | 3 | 12 | 15 | 6 | 6.9 | 7
- G1/4 | 18 | 3 | 12 | 15 | 6 | 6.9 | 7
- M14x1.5 | 19 | 3 | 12 | 15 | 6 | 6.9 | 7
- M16x1.5 | 21 | 3 | 12 | 15 | 8 | 9.2 | 7.5
- G3/8 | 22 | 3 | 12 | 15 | 8 | 9.2 | 7.5
- M18x1.5 | 23 | 4 | 12 | 16 | 8 | 9.2 | 7.5
- M20x1.5 | 25 | 4 | 14 | 18 | 10 | 11.4 | 7.5
- G1/2 | 26 | 4 | 14 | 18 | 10 | 11.4 | 7.5
- M22x1.5 | 27 | 4 | 14 | 18 | 10 | 11.4 | 7.5
- M24x1.5 | 29 | 4 | 14 | 18 | 12 | 13.7 | 7.5
- M26x1.5 | 31 | 4 | 16 | 20 | 12 | 13.7 | 9
- M27x2 / G3/4 | 32 | 4 | 16 | 20 | 12 | 13.7 | 9
- M30x1.5 / M30x2 | 36 | 4 | 16 | 20 | 17 | 19.4 | 9
- M33x2 / G1 | 39 | 5 | 16 | 21 | 17 | 19.4 | 9
- M36x1.5 / M36x2 | 42 | 5 | 16 | 21 | 19 | 21.7 | 10.5
- M38x1.5 / G1 1/8 | 44 | 5 | 16 | 21 | 19 | 21.7 | 10.5
- M39x2 | 46 | 5 | 16 | 21 | 19 | 21.7 | 10.5
- M42x1.5 / M42x2 / G1 1/4 | 49 | 5 | 16 | 21 | 22 | 25.2 | 10.5
- M45x1.5 / M45x2 | 52 | 5 | 16 | 21 | 22 | 25.2 | 10.5
- M48x2 / G1 1/2 | 55 | 5 | 16 | 21 | 24 | 27.4 | 10.5
- M52x1.5 / M52x2 | 60 | 5 | 16 | 21 | 24 | 27.4 | 10.5
- G1 3/4 | 62 | 5 | 20 | 25 | 32 | 36.6 | 14
- M56x2 | 64 | 5 | 20 | 25 | 32 | 36.6 | 14
- M60x2 / G2 | 68 | 5 | 20 | 25 | 32 | 36.6 | 14
- M64x2 | 72 | 5 | 20 | 25 | 32 | 36.6 | 14
Worked example: M16x1.5 plug
An M16x1.5 DIN 908 plug has a 21 mm collar, 3 mm thick, 12 mm of thread and is about 15 mm long. It takes an 8 mm hex key, which must go at least 7.5 mm deep.
Common problems
- Weeps oil: no sealing ring under the collar, or the port face is rough.
- Will not start: wrong pitch, such as M30x2 in an M30x1.5 port, or a G plug in a metric port.
- Rounded socket: the hex key was worn or not fully seated to depth t.
FAQ
What is DIN 908?
A screw plug with a collar and a hexagon socket, with parallel thread, used to close oil, hydraulic and gearbox ports.
Why do some rows list two threads?
DIN 908 gives the same plug dimensions for a metric fine thread and the matching G pipe thread.
Why is G1/2 thread length 14?
One source shows 1, which is a typo; the other sources give 14, the same as M20x1.5 and M22x1.5.
Does the plug seal on its thread?
No. Parallel thread does not seal; use a sealing ring under the collar.
Related guides and calculators
- Sealing rings (DIN 7603)
- Light screw plugs (DIN 7604)
- Hex head screw plugs (DIN 910)
- Pipe nuts (DIN 431)
- Hex nuts (ISO 4032)
- Wrench size chart
- All free machinist calculators
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