The 8.6 x 4 mm steel-braided high-pressure grease hose carries an 80 MPa burst rating and a 28 MPa recommended working pressure, linking pumps, divider valves, and bearing points wherever rigid tubing cannot follow the machine.
What This Hose Is
Three layers make up the hose: an NBR inner tube carrying the lubricant, a single steel wire braid resisting pressure, and an abrasion-resistant cover. The 4.0 mm bore and 8.6 mm outside diameter are dimensionally compatible with common centralized lubrication systems. Weighing hose against rigid tubing? Our tubing and hose selection guide covers the trade-offs.
Technical Specifications
| Parameter | Value |
|---|---|
| Inner diameter | 4.0 mm (+/-0.1 mm) |
| Outer diameter | 8.6 mm (+0.15/-0.1 mm) |
| Wall thickness | 2.3 mm nominal |
| Construction | NBR inner tube, single steel wire braid, abrasion-resistant cover |
| Burst pressure | 80 MPa (800 bar / 11,600 PSI) |
| Proof pressure | 56 MPa (560 bar / 8,120 PSI) |
| Recommended working pressure | 28 MPa (280 bar / 4,060 PSI) |
| Pulsating duty | 20 MPa |
| Minimum bend radius | 50 mm static / 75 mm dynamic |
| Temperature range | -40°C to +100°C (NBR); -20°C to +120°C (FKM option) |
| Media | NLGI 000-2 grease and mineral-oil-type lubricating oil |
Pressure Ratings and Derating
The 80 MPa figure is burst pressure, not a service target. Recommended working pressure is 28 MPa, a burst-to-working ratio of 3:1; pulsating lines should plan around 20 MPa for 4:1. Most centralized grease systems run at 10 to 25 MPa.
Above +60°C, derate about 1 percent per degree, leaving roughly 70 percent of capacity at +100°C. Lines that run hot continuously should use the FKM tube version, rated -20°C to +120°C.
Where It Fits in a Centralized System
- Pump outlet line from the reservoir unit to the main trunk.
- Main trunk routed along the frame toward the divider valves.
- Secondary feeds from each divider valve outlet to the bearings.
- Flexible connections across joints and slides where rigid tube would fatigue.
In a typical centralized grease lubrication system, the divider valves meter each shot; the hose simply holds pressure and survives the routing.
Applications
Typical installations: machine tools, presses, stamping lines, wind turbine yaw and pitch bearings, conveyors, and mobile equipment, anywhere a lubrication point moves or vibrates.
Installation and Routing
Respect the bend radius: 50 mm for static lines, 75 mm where the hose flexes. Leave a straight run of at least twice the outside diameter, about 17 mm, after each fitting. Clamp the hose against chafe and never twist it during assembly; a twisted braid loses much of its fatigue life.
Fittings and Cut Lengths
End connections cover BSPP G1/8 and G1/4, NPT 1/8″ and 1/4″, metric compression, JIC 37 degree flare, and 6 mm push-in. The straight hose stud and elbow hose stud are dedicated to this bore, the elbow suiting tight routing. Rolls come in 10, 25, 50, and 100 m, cut to length on request. For larger trunks, see the 11.2 x 6.3 mm high-pressure lubrication tube.
What Is Supplied
Each order covers the hose in the agreed length, the fittings you specify, and fitting assembly where requested. A pre-fill grease service is available: state the grease grade when ordering and install within 30 days. To size a line, contact us for a quote.
Frequently Asked Questions
Why is the working pressure only 28 MPa when the burst pressure is 80 MPa?
Burst is the destruction point under a static bench ramp. Working pressure keeps a 3:1 burst-to-working ratio so the line tolerates pump pulses, cold grease, and years of flexing. On pulsating duties, design around 20 MPa for 4:1.
How do I choose between this hose and a nylon tube?
Use braided hose where pressure is high, the line moves, or vibration is severe. Rigid nylon suits short, static, low-pressure runs: compare the 6 x 1.5 mm polyamide tube and the helical coil nylon pipe for axes that travel.
Can NLGI 2 grease run at 25 MPa?
Yes. The hose is rated NLGI 000-2, and 25 MPa sits within the working range. On long runs or in low temperatures, prefer NLGI 1 or 0 to keep line pressure reasonable.
Why does the minimum bend radius matter?
Bending tighter than 50 mm static or 75 mm dynamic kinks the steel braid. The cover can look fine while the wires fatigue inside, leading to early weeping near the fitting.
How do I pick the end fittings?
Match the thread on your equipment: BSPP G1/8 or G1/4 on most lubrication hardware, NPT 1/8″ or 1/4″ on tapered threads, metric compression, JIC 37 degree flare seats, or 6 mm push-in.
Can this hose carry hydraulic oil?
Mineral-oil-type oil is fine for the NBR tube. Water-based and phosphate-ester fluids attack NBR, so order the FKM version for those media.
How do I order the pre-fill grease service?
State the grease grade when ordering and we fill the assembled line. Install within 30 days so the pre-fill stays homogeneous and the first cycle behaves predictably.
How do I prevent early failure at the fitting?
Keep a straight run of at least twice the outside diameter, about 17 mm, behind each fitting, clamp the hose so it cannot rub, and tighten without twisting the body.
When must the hose be replaced?
Inspect periodically and replace on condition. Triggers: a cracked, swollen, or bulging cover, grease weeping at a fitting, a kink or flat spot, or a hose that has stiffened noticeably.
How do I get a quote and cut-to-length hose?
Send your fitting list, lengths, and grease grade via the quote request page or write to inquiry@isohitech.com. IsoHiTech Lubrication Systems, founded in 2023, engineering since 2006, replies with a configured assembly in your cut lengths.
