So... I'm lazy and wanted to be able to grease the bearings while they were mounted to their respective parts of the printer. So just disassemble as little as possible, remove the rod and then grease away...
...but the grease tube was always in the way or the bearing was somehow blocked and the tool couldn't reach far enough.
This is my first try on this problem and it should extend far enough, and be thin enough, to reach all bearings on my MK3 (especially the lower X-axis bearing and the Y-axis bearings) without having to disassemble everything.
This has an M14x1.5 threading and will fit an 3oz. Super Lube tube.
Now with a cap... =^_^=
I've also changed the inner diameters. In the main part it's bigger and in the top part it's smaller. Hoping to have a more stable upper part that way.
The top diameter was also changed a bit.
If you downloaded a previous version please re-download the files.
Another greasy problem-solver is right here:
Grease extension with a 45° angle to get the tube out of the way.
The Fusion 360 file is included.
This Thing was inspired by or got useful infos from:
Update 2019-01-11: LMU12 Version added on request. Make sure you use the v2 cap.
I've set the perimeters for the upper, more fragile, part to 4 - this way the part that is actually inside the bearing should be more stable.