I fixed my keyboard with a tiny 3d printed part.
The model is available on Github: MannyAdumbire/trackpoint-shroud-lenovo-thinkpad
After years of heavy use, It became difficult to move the mouse/trackpoint on all three Lenovo TrackPoint II keyboards,
To try and fix the issue, I removed the rubber nub that covers the trackpoint to reveal what I’ll call a plastic shroud. Since I couldn’t find diagrams or repair guides on line, I guessed that the 4 metal sensors just below the shroud are used to generate mouse movements based on which feet are making contact and with how much force.
Looking closely at the plastic shrouds, they all showed some amount of damage to the contact edges. I decide to 3d model and print replacement parts.
When sending to the 3d printer, I used the highest print layer resolution which is .12 mm on an Flashforge Adventurer 3. This tiny print took 5 minutes to complete. I noticed some imperfections, but the print fit as snugly as the original part. It only added a tiny bit of extra height compared the original. Most importantly though, the mouse pointer moves like new again!