Superlube 21030 works great for 3D printer bearings. I want to put some into my Sainsmart 3018 pro desktop router, but the bearings are 10mm inner diameter, 30 mm length (and 58 mm length). I remixed the LMU8 bearing injector to fit a 10mm bearing, and lengthened it to fit the 30 mm length. For the 58 mm long bearings, I'll inject grease from both ends. The uepsi models I found on printables (prusaprinters) didn't seem to have the correct threading for the superlube tubes.
I printed this on my prusa mk3s+ with 0.2mm layer height (adaptive layers), in ruby red PETG.
This worked fine for injecting superlube grease into my Sainsmart 3018-pro CNC router bearings.
The lmu8 grease injector model by Uepsi was remixed on thingiverse by ri3del (https://www.thingiverse.com/thing:3678611), to match the M14x1.75mm thread on the superlube tube. I remixed the M14x1.75mm threaded version to fit a LMU10 bearing, and extended the length to 30mm so that it can work with the 10mm diameter, 30 mm and 58 mm long bearings in my sainsmart 3018-pro desktop router.
I also added the 8mm injector model (step, stl, 3mf) directly from ri3del onto this page. The original ri3del model is an 8mm diameter, 22mm length grease injector, also with a M14x1.75mm thread that matches the superlube tube perfectly.
The author remixed this model.