Here is some guidance on Friction Hinge maintenance.
Initial Installation Checks
The friction hinges produced by Nico provide long life service with only minimal maintenance required. On initial installation please ensure the hinge channel is secured to the frame and is free of any debris. Adjust the friction screw in the slide to give a smooth operation to the opening of the vent.
All the pivot points and the nose cap on the friction hinge are lubricated during manufacture. We recommend inspection/maintenance every 5000 cycles, lubricating the rivet points and the nose cap as required. Use light machine oil for this and any additional lubrication which may be beneficial, taking care that the lubricant does not stain the window.
Please do not use any type of penetrating oil (e.g. WD40, Duck Oil) on Nico friction hinges. These oils adversely affect the friction hinge slide.