Lubricating a linear guide carriage
2024-05-14
At the heart of a linear guide system, there are three main components responsible for transferring loads from the moving part to the machine frame: the carriage body (also known as the slide, runner block, or guide shoe—many names, same thing), the balls, and the rail, all with their respective ball tracks.
To allow the balls to run continuously over an unlimited stroke, components are needed to move the balls from the load zone, through a return channel, and back again. These guiding components are called recirculation pieces.
To get the most out of your linear guide, it’s important to lubricate the carriage regularly. How often depends on several factors:
- Load
- Dirt and debris
- Humidity
- Temperature
- Quality of the lubricant
A high-quality lubricant will go a long way in extending the lifespan of your linear guide.
Carriages usually have two or more ports for grease nipples, typically located in the recirculation pieces. In most cases, you only need to use one of these. If your stroke is very short, it's a good idea to grease from both ends.
Most linear carriages come with ports made of plastic, and often these aren't threaded from the factory. Instead, you screw the grease nipple straight into the plastic, letting it form its own thread. This can sometimes result in misaligned threads—or worse, the recirculation housing could crack, rendering the carriage unusable.
The carriage shown in the video below has eight lubrication ports(!) to let you install the grease nipple wherever access is easiest. It also supports metal-threaded grease nipples, so you get a solid, properly aligned connection every time.
In linear guides, there are extremely tight tolerances between the balls and ball tracks, which is why keeping out contaminants is critical. Even tiny particles can act like abrasives and wear out the system prematurely. That’s why carriages are equipped with various types of seals.
Typically, you’ll find seals around the rail profile itself, but many carriages also come with longitudinal seals beneath the ball tracks (standard on some models, optional on others), and in rare cases even above the ball tracks—everything to keep the balls as clean as possible.
Some carriages also have internal components that distribute the lubricant directly to the balls, ensuring consistent lubrication exactly where it's needed.
For certain linear guide setups, you can also use cover strips to seal over the mounting holes in the rail. This provides a smoother surface for the seals to glide over and helps reduce contamination.
Check out this video with Carry Lindholm from Bosch Rexroth for more insights:
