Grease nipple caps are molded covers for DIN 71412 conical-head grease nipples, keeping out dust, sand, splash water, and washdown spray between grease services. This page covers the accessory only: caps for conical heads from M6 through M10. The nipples themselves are covered on the DIN 71412 grease nipple family page and the M8 grease nipple page. Flush concave-head nipples cannot take these standard caps; see the DIN 3405 concave nipple page.
Which Nipples These Caps Fit
These caps fit DIN 71412 conical-head nipples from M6 to M10 in M6x1, M8x1, M10x1, 1/4″-28 UNF, and 1/8″-27 NPT. The cap grips the head, not the thread: match the cap inside diameter to the head diameter and check the closed height clears the nipple. Taller nipples can take custom taller caps.
| Dimension | Specification |
|---|---|
| Cap inside diameter | 6.2 – 12.1 mm |
| Cap height | 13 – 22 mm, custom taller available |
| Wall thickness | 1.5 – 3.0 mm |
| Nipple protrusion accommodated | up to 18 mm |
| Molding tolerance | +/- 0.1 mm |
Materials and Temperature Range
LDPE suits general industrial, fleet, and indoor use. PE-LLD adds tear and puncture resistance for heavy industry and outdoor exposure. TPE keeps its elastic grip for cold storage, high vibration, and frequent removal.
| Material | Temperature range | Typical use |
|---|---|---|
| LDPE | -40°C to +80°C | General industrial, fleet, indoor |
| PE-LLD | -50°C to +85°C | Heavy industry, mining, construction, outdoor |
| TPE | -70°C to +85°C | Cold storage, high vibration, frequent removal |
Fitting and Retention Styles
Snap-on is the most common, clicking over the head with tactile and audible confirmation. Push-fit suits high-frequency maintenance; press-fit is an interference fit for high-vibration points; internal ribbed grip adds retention against handling or snagging.
Retention comes in three tiers: untethered standard caps for non-critical points, tethered strap caps that stay attached during greasing, and fixed chain or cable for rotating critical equipment.
Color Coding for Maintenance
Caps come in ten standard colors: red, blue, green, yellow, black, white, orange, purple, tan, gray, plus custom. Color coding is a customer-defined convention: each plant or fleet maps color to grease type and schedule. Right Product matches cap color to the grease gun color band; Right Location separates crowded points; Right Schedule marks greasing frequency.
Chemical Compatibility and What the Cap Stops
The materials tolerate petroleum-based and synthetic industrial lubricants and conditions from pH 4 to 10. The cap stops dust, sand, splash water, and washdown spray from reaching the fitting. A cap is a contamination and spray barrier, not a pressure seal. For the wider hardware picture, see the grease fitting types guide.
Honest Limitations
- The cap’s temperature limit is its own, not the working temperature of the lubrication point. Points beside exhaust or an oven can exceed the cap range even where the grease is fine; choose the higher-rated material or a metal guard.
- These caps are shaped for DIN 71412 conical heads; flush concave-head nipples cannot take them.
- In high-UV outdoor service, choose PE-LLD or TPE and inspect regularly for embrittlement, discoloration, or loss of elasticity.
- For food or pharmaceutical environments, material compliance is confirmed case by case; we make no certification claims here.
If your case sits outside these ranges, send us your nipple sizes, materials, and duty details to confirm supply.
Frequently Asked Questions
How do I measure to pick the right cap?
Match the cap inside diameter to the conical head diameter; 6.2 – 12.1 mm covers M6 to M10 heads, with protrusion up to 18 mm. Choosing the nipple itself? Start with the DIN 71412 family page or the M8 page.
Which material should I choose?
Work on three axes: temperature, impact, and removal frequency. LDPE covers -40°C to +80°C for general indoor and fleet use; PE-LLD covers -50°C to +85°C for heavy and outdoor duty; TPE covers -70°C to +85°C for cold storage, vibration, and frequent removal.
Can the caps be reused?
Yes – reusable when clean and undamaged. Replace when it turns brittle, changes color, loses elasticity, tears, or fits loosely.
How does color coding work?
Color coding is your own convention: the plant maps cap color to grease type and schedule. Right Product matches cap color to the grease gun color band; Right Location separates crowded points; Right Schedule marks greasing frequency.
Is the cap’s temperature limit the same as the grease’s?
No. The cap’s range is the cap’s own limit, not the working temperature at the lubrication point. High-temperature points need the higher-rated material or a metal guard.
Do flush concave-head nipples take these caps?
No. These caps grip conical heads; concave flush nipples sit in a cupped recess below the surface and give them nothing to grip. The DIN 3405 page covers that form.
When do I need a tether or chain?
Use tethered strap caps where removed caps get lost in maintenance, and fixed chain or cable on rotating critical equipment. Non-critical points can stay untethered.
Can the caps be used around food or pharmaceuticals?
We confirm material compliance case by case for your contact and cleaning regime, with no certification claims here; share the details and we will confirm what the material data allows.
What about high-UV outdoor service?
Choose PE-LLD or TPE for outdoor exposure and inspect regularly; replace at the first sign of embrittlement, discoloration, or loss of elasticity.
Who supplies them?
IsoHiTech Lubrication Systems is a lubrication equipment supplier founded in 2023, engineering since 2006. Send drawings or head sizes to inquiry@isohitech.com, or use our contact form, and we will confirm the right caps for your application.
