A remote grease line with 6 mm nylon tube and compression fittings carries grease from a gun connected at a safe, accessible station to a bearing’s original fitting point, so the technician no longer climbs or crawls to the bearing. Parts catalogs list this assembly under remote grease line fittings – 6 mm nylon tube with compression fittings – and the full component list is in the remote grease line kit guide. The tube is semi-rigid PA12 nylon: 6 mm outside diameter, 3 mm inside diameter, 1.5 mm wall, rated to 89 bar (1,291 PSI) working pressure from -60°C to +80°C. This page covers the 6 mm tube, its compression fittings, and the length limits by gun type; for larger tube sizes and the reusable fitting families, see the remote grease line system page.
How the Compression Fitting Works
Each grease line compression fitting has three parts: a nut, an olive, and a body. Tightening the nut drives the olive onto the tube, and the olive deforms to grip and seal the tube wall. That deformation is the seal, so the olive is single-use: every time a connection is remade, fit a new olive. The nut and body can be reused. Bodies come in straight and 90-degree versions, in brass or stainless steel, with BSP, NPT, or metric threads. Fittings here are sized for 6 mm OD tube; a 1/4″ fitting is dimensionally close but not interchangeable.
Specifications
| Item | Specification |
|---|---|
| Tube size | 6 mm OD / 3 mm ID, 1.5 mm wall |
| Tube material | PA12 nylon, semi-rigid (holds shape but bends) |
| Working pressure | 89 bar (1,291 PSI) |
| Burst pressure | 267 bar (3,873 PSI), a destructive limit, never a working value |
| Temperature range | -60°C to +80°C; stays flexible in cold weather |
| Minimum bend radius | 36 mm; tighter bends kink the tube |
| Supply | 25 m and 100 m rolls; custom lengths cut to order |
| Fitting material | Brass or stainless steel |
| Fitting bodies | Straight and 90-degree |
| Thread options | BSP, NPT, metric |
| Max line length by gun | 5 m manual gun / 2 m electric gun / 3-4 m air-powered gun |
| Anchor block | One station serves 4-6 points, each point on its own line |
Pressure note: match the tube rating to the grease gun’s output. A manual lever grease gun can produce 10,000-15,000 PSI, far above the 89 bar rating of 6 mm tube. If high-pressure manual guns are used, specify a larger tube size as shown on the remote grease line system page.
Installation and Line Length
- Plan the route and measure each run; respect the length limit for your gun type.
- Cut the tube square with a tube cutter. Do not use a knife; a knife leaves a stress notch in the tube wall.
- Push the tube into the fitting past the olive.
- Tighten hand-tight, then about 1.5 turns with a wrench. Do not overtighten; excess torque damages the tube.
- Keep every bend at 36 mm radius or larger, and pump grease to check each joint.
Kits ship with the tube cut to length, compression fittings with nuts and olives, an anchor block with nipples, a tube cutter, mounting clips, and an instruction sheet. One anchor block station serves 4-6 lubrication points, each on its own dedicated line. For tube and fitting selection across sizes, see the selection guide; the 4 mm vs 6 mm comparison covers the smaller option. To order, contact us for a quote.
Frequently Asked Questions
What is a remote grease line?
A permanently installed line from a bearing’s grease fitting to a nipple on an anchor block at an accessible location, so hard-to-access points are serviced from the block without climbing or crawling.
Does 6 mm refer to the outside or inside diameter?
The outside diameter. The tube measures 6 mm OD and 3 mm ID with a 1.5 mm wall.
Can I use 1/4″ fittings on 6 mm tube?
No. The sizes are close but not interchangeable. Use fittings designed for 6 mm OD tube so the olive grips and seals correctly.
How long can one line be?
Up to 5 m with a manual gun, 2 m with an electric gun, and 3-4 m with an air-powered gun. Longer runs need a larger tube size.
Can I use a high-pressure manual lever grease gun?
No. A manual lever gun can produce 10,000-15,000 PSI, far above the 89 bar rating of this tube. For high-pressure manual greasing, move to a larger tube size on the system page.
Can I treat the burst pressure as the working pressure?
Never. The 267 bar figure is the destructive test limit of the tube, not an operating value. The working limit is 89 bar (1,291 PSI).
What causes leaks or tube pull-out at the fittings?
The usual causes are an angled or rough cut, an olive that was not seated or was reused, overtightening, and bends tighter than 36 mm. Recut square, fit a new olive, and retighten about 1.5 turns past hand-tight.
Does the tube work in freezing weather?
Yes, down to -60°C. PA12 nylon stays flexible in the cold, unlike cheaper plastic tube.
Grease is not arriving at the far bearing. What should I check?
Check for a kinked or flattened section, a blocked fitting, grease that has hardened in the line, and a run that exceeds the length limit for the gun type. Correct the routing or shorten the line, then reprime until grease appears at the bearing.
Related Pages
- Remote grease line system with reusable fittings
- Grease line tubing and fittings selection guide
- 4 mm vs 6 mm nylon pipe for lubrication
- Grease line fittings category
- Lubrication accessories
- Grease fitting types guide
To order 6 mm tube, compression fittings, or complete kits cut to length, contact us for a quote with your gun type, run lengths, and thread standard.
