The M5 x 0.8 grease nipple is a non-family metric size: the 5 mm port thread sits outside the M6 – M14 list on our DIN 71412 grease nipple family page. It serves compact bearings, small vehicle electrical components, and precision transmissions where the port is already cut to M5. If your port is M4, the dedicated M4 grease nipple page is the reference; for M6 and larger, use the family page. Angled bodies are covered on the angled grease nipples page.
Where the M5 x 0.8 Size Fits
DIN 71412 defines the common metric family from M6 to M14. The M5 x 0.8 thread is a non-family size, yet some compact component makers still cut M5 ports. When the port is already M5, this page is the reference; do not adapt another thread to force a fit. See the grease fitting types guide and the grease line fittings category for background.
Specifications and Dimensions
Key dimensions are below. Variants exist across suppliers, so confirm when ordering.
| Item | Specification |
|---|---|
| Thread | M5 x 0.8 |
| Hex across flats | 7 mm |
| Overall length | 15 mm typical; variants 12 – 18 mm |
| Thread engagement | 5 – 6 mm |
| Head diameter (hydraulic type) | 6.5 mm |
| Ball diameter | 3.5 mm (3.0 – 4.0 mm) |
| Bore diameter | 1.5 – 2.0 mm |
| Grease gun injection pressure | Compatible up to 400 bar |
| Spring preload, standard closing force | 15 – 25 N |
| Seal type | Spring-loaded ball check |
Materials and Working Temperature
Four material options cover most M5 applications. The 303 (1.4305) free-machining grade appears here because M5 users often want lower machining cost stainless for dry indoor duty.
| Material | Hardness | Working temperature | Notes |
|---|---|---|---|
| Zinc steel 1.0718 (11SMnPb30+C) | Head 550 HV minimum | -40°C to +120°C | Zinc-plated and passivated; general use |
| 303 (1.4305) stainless | HRB 85 – 95 | Confirm when ordering | Free-machining; lower machining cost than 316L; general industrial and dry indoor use; not for chloride environments |
| 316L (1.4404) stainless | HRB 85 – 95 | Confirm when ordering | Marine, chemical, and washdown exposure |
| Brass CW614N | HRB 55 – 75 | -50°C to +200°C | General use; softer body, lower torque |
Available Configurations
Straight Form A is the default, typically 15 mm long. The 45° Form B holds its angle within +/- 2° with 1.5 mm wall at the bend. The 90° Form B suits a perpendicular approach but runs a pressure drop roughly 5 – 10% higher than straight. Button heads follow DIN 3404 with a 10 – 12 mm head, need the dedicated coupler, and support injection up to 1,034 bar / 15,000 PSI. Flush heads follow DIN 3405 and are covered on the DIN 3405 page. For 45° and 90° detail, see the angled grease nipples page.
Installation and Torque
Clean the port and verify the thread with a gauge. Start the nipple by hand for 2 – 3 turns, then torque with a 7 mm socket. Do not add PTFE tape or liquid sealant; debris can contaminate the port and ball check. Torque zinc steel and stainless steel to 5 – 8 Nm, brass to 4 – 6 Nm. Run one grease gun stroke to confirm grease reaches the bearing.
Grease Compatibility
The M5 nipple works with NLGI #0 through NLGI #3, NLGI #2 most common. Mineral and synthetic oil bases both work. Match the grease to the bearing manufacturer’s specification.
Limitations
M5 x 0.8 is a non-family size, so availability is narrower than M6 – M14; confirm stock when ordering. The 303 (1.4305) option does not resist chlorides; marine, chemical, and washdown duty needs 316L (1.4404). The 90° form runs a 5 – 10% higher pressure drop than straight. Button heads work only with their dedicated coupler. If unsure which configuration fits, ask our team for a quote.
Frequently Asked Questions
Is M5 x 0.8 a standard size in the DIN 71412 family?
No. The DIN 71412 family page lists M6 through M14, so M5 x 0.8 is non-family. Use it when the port is already M5, as on compact bearings, small vehicle electrical parts, and precision transmissions.
Should I choose an M5 or an M4 grease nipple?
Match the thread already cut in the port; do not guess or adapt. The M4 grease nipple page covers M4 in full; for M5, this is the reference.
Which configuration should I choose: straight, 45°, 90°, or button head?
Choose by access space: straight Form A for a head-on approach, 45° or 90° Form B for blocked access, DIN 3404 button head for the button head coupler. The angled grease nipples page compares 45° and 90° bodies.
What torque should I use to install an M5 grease nipple?
5 – 8 Nm for zinc steel and stainless steel bodies, 4 – 6 Nm for brass, with a 7 mm socket.
What grease gun injection pressure is compatible?
Up to 400 bar, matching the family spec for grease gun injection pressure.
Should I choose 303 (1.4305) or 316L (1.4404) stainless?
Choose 303 (1.4305) for general industrial and dry indoor use; it does not resist chlorides. Choose 316L (1.4404) for marine, chemical, or washdown exposure.
Do I need thread sealant when installing?
No. Metric grease nipples seat on the thread flank without sealant; PTFE tape or paste can leave debris in the port. Start by hand for 2 – 3 turns, then torque to spec.
What grease grades work with an M5 nipple?
NLGI #0 through NLGI #3, with NLGI #2 most common; mineral and synthetic oil bases both work.
When should I replace an M5 grease nipple?
Replace it when the ball check no longer closes, threads are damaged or galled, the head cracks or deforms, or it keeps loosening at correct torque. In corrosive service, inspect the plating for pitting.
Who is IsoHiTech?
IsoHiTech Lubrication Systems is a lubrication equipment supplier founded in 2023, engineering since 2006. For M5 x 0.8 grease nipple inquiries, send your port thread, material, and configuration requirements to inquiry@isohitech.com or request a quote through our contact page.
