Overview
The M10 grease nipple is a metric hydraulic-type lubrication fitting built to DIN 71412, with a 10 mm thread diameter in three pitches: M10 x 1.0, M10 x 1.25, and M10 x 1.5. It screws into a metric-tapped port and gives a standard grease gun coupler a secure connection point.
Thread form follows ISO 261 / DIN 13-1, with a 6g external tolerance per ISO 965-1. A spring-loaded ball check valve opens under gun pressure to admit grease, then reseats to keep lubricant in and contaminants out.
Specifications
| Parameter | Specification |
|---|---|
| Thread sizes | M10 x 1.0 / M10 x 1.25 / M10 x 1.5 |
| Thread standard | ISO 261 / DIN 13-1 |
| Thread tolerance (external) | 6g per ISO 965-1 |
| Hex size (across flats) | 11 mm (SW11) |
| Head diameter | 6.5 mm (DIN 71412 hydraulic type) |
| Thread length | 5.5 mm |
| Overall length | Form A straight 15 mm / Form B 45° 25 mm / Form C 90° 20 mm |
| Ball / orifice diameter | 3.5-4.5 mm / 1.8-3.2 mm |
| Max working pressure (declared spec) | Standard type 150 bar (2,175 PSI); high-pressure type 400 bar (5,800 PSI) |
| Tightening torque | M10 x 1.0: 10-12 Nm; M10 x 1.25: 10-15 Nm; M10 x 1.5: 15-20 Nm; stainless steel and brass: reduce 10-15% vs steel |
| Temperature range | Zinc-plated carbon steel: -40°C to +120°C |
M10 x 1.0, 1.25, or 1.5: Confirm the Pitch First
“10 mm grease fitting” is ambiguous – it can mean the thread diameter or loosely a wrench size. Every M10 order must state the pitch. Identify a port with a pitch gauge, or measure 10 threads with a caliper: 10.0 mm is M10 x 1.0, 12.5 mm is M10 x 1.25, 15.0 mm is M10 x 1.5.
M10 is close in size to 1/8 BSP but never interchangeable: thread form and pitch differ, and forcing the fit damages both threads.
| Application | Recommended pitch |
|---|---|
| Precision machinery, high-vibration points, thin-walled parts | M10 x 1.0 |
| General industrial and automotive equipment | M10 x 1.25 |
| Heavy-duty equipment, thick-walled castings | M10 x 1.5 |
Configurations
Straight Form A (15 mm) suits open, head-on access. Form B 45° (25 mm) and Form C 90° (20 mm) clear obstructions; as a declared figure, angled bodies add roughly 5-10% pressure drop versus straight. More detail: angled grease nipples and the 90 degree grease nipple page.
The button head variant (DIN 3404) uses a 10-16 mm head, delivers 2-4x the flow of a standard hydraulic head, needs a dedicated coupler, and carries a declared working pressure up to 15,000 PSI (1,034 bar) – details on the DIN 3404 button head fittings page.
The flush-type variant (DIN 3405) protrudes 0-2 mm; it needs a pre-machined counterbore and low-profile coupler.
Materials
| Material | Typical use |
|---|---|
| Zinc-plated carbon steel (free-machining 1.0718 type) | General industrial, automotive, indoor machinery; -40°C to +120°C |
| Stainless steel 303 (1.4305) | Moderate corrosion exposure; free-machining requirements |
| Stainless steel 316L (1.4404) | Marine, coastal, and chemical processing environments |
| Brass CW614N (CuZn39Pb3) | Non-ferrous, non-sparking, and hydraulic applications |
For stainless steel and brass, reduce tightening torque by 10-15% versus steel to avoid thread galling.
Installation
- Confirm the port thread and pitch with a pitch gauge; metric and imperial threads are not interchangeable.
- Clean the tapped port; remove burrs, chips, and old sealant residue.
- Start the nipple by hand for 2-3 full turns to prevent cross-threading.
- Do not apply PTFE tape or thread sealant; debris can contaminate the lubrication system.
- Tighten with an 11 mm socket to the torque for your pitch and material.
- Verify with the grease gun (typically 3,000-5,000 PSI / 207-345 bar): valve opens, grease flows, no thread-joint leakage.
Request a quote for pitch, material, and body combinations.
Maintenance
Inspect regularly. Replace the nipple if the ball valve fails to reseat, threads are stripped, the hex rounds off, or thread-joint leakage persists after re-torquing. Replacement is condition-based, not calendar-based; frequency depends on environment and service pressure.
FAQ
What is an M10 grease nipple?
A metric hydraulic-type fitting built to DIN 71412, with a 10 mm thread in 1.0, 1.25, or 1.5 mm pitch. A ball check valve inside admits grease under gun pressure and reseals afterwards.
How do I tell M10 x 1.0, 1.25, and 1.5 apart?
Use a pitch gauge, or measure 10 threads with a caliper: 10.0 mm is M10 x 1.0, 12.5 mm is M10 x 1.25, 15.0 mm is M10 x 1.5. Confirm the pitch before ordering or re-tapping.
What does “10 mm grease fitting” actually mean?
It is ambiguous – thread diameter or loosely a wrench size. This page covers the M10 metric thread only; always order by the full designation, M10 x pitch.
Is M10 interchangeable with 1/8 BSP?
No. The sizes are close, but thread form and pitch differ. Forcing the fit damages both threads and leaves a leak path.
Does a finer pitch allow higher tightening torque?
No. Torque follows the specification table: 10-12 Nm for M10 x 1.0, 10-15 Nm for M10 x 1.25, 15-20 Nm for M10 x 1.5, reduced 10-15% for stainless steel and brass.
Which material should I choose?
Zinc-plated carbon steel for general industrial use; stainless 303 for moderate corrosion exposure; stainless 316L for marine and chemical environments; brass CW614N for non-ferrous or non-sparking requirements.
Straight, 45°, or 90° – which form do I need?
Straight Form A where the gun couples head-on; Form B 45° or Form C 90° where access is obstructed. Declared pressure drop for angled bodies is roughly 5-10% versus straight.
What is a button head M10 grease nipple?
A DIN 3404 variant with a 10-16 mm head, 2-4x the flow of a standard hydraulic head, up to a declared 15,000 PSI (1,034 bar). It needs a dedicated coupler – standard hydraulic couplers will not fit.
Can I use PTFE tape or sealant on the threads?
No. Sealant debris can contaminate the lubrication system. Clean and deburr the port, hand-start 2-3 turns, and tighten to the specified torque instead.
How do I verify a new M10 fitting after installation?
Pump the grease gun (typically 3,000-5,000 PSI / 207-345 bar): the ball valve opens, grease flows, no leakage at the thread joint. To confirm pitch, material, or body form, contact our team for a quote – IsoHiTech Lubrication Systems, founded in 2023, engineering since 2006; inquiry@isohitech.com.
How do I remove a seized M10 grease nipple without cracking the housing?
Penetrating oil at the thread first, and time for it to work. Then break the fitting loose with the correct-size wrench or socket on the hex — steady torque, not shock. If it will not move, gentle heat on the surrounding housing (not the fitting) helps on steel and cast parts; on soft aluminum housings skip the heat and re-soak instead. Never extend the wrench for extra leverage: M10 threads in a soft boss strip before the fitting lets go. Once out, chase the thread and install a new nipple rather than reusing the damaged one. For the blocked-fitting side of the problem, see our grease nipple troubleshooting guide.
Why does my coupler keep slipping off the M10 nipple under pressure?
Usually wear, not the thread. The coupler grips the fitting’s conical head with spring-loaded jaws; a worn or ball-damaged head, tired coupler spring, or misaligned approach all let it blow off under pressure. Inspect the head: a rounded shoulder, damaged ball seat, or burrs from a previous slip mean the nipple needs replacing. If the head is clean, rebuild or replace the coupler. Slipping under pressure is also a safety issue — grease at system pressure injects through skin.
