These bearing adapter can mount the IGUS RJM-01 (and maybe the RJMP-01) bearings on the ultrabase printbed. The design has been optimised to fix the bearing without squeezing it to much, so the bearing will not be deformed. the printbeds height remains the same as with the stock bearings. The design will be tested during the next days/weeks, hopefully there will not be the need to insert retaining rings to hold the bearing in place. Current design allows the use of a single bearing, maybe i will upgrade it to a double bearing version after the basic design is tested. For the current test, i used 0.15 layers of nx2 pla from extrudr, which actually sticks like hell on the ultrabase printbed (; (200°C, 60°C).
Update 07.05.: After several successful prints, a small part print with lots of quick directions changes of the printhead failed due to movement of the bearing in the holder. I will try to print a version with a bit smaller outcut for the bearing to try to avoid the use of retaining rings. Upgraded version upcoming.
Update: 15.05.18: I designed a dual bearing version of the adapter, that can be secured by two retaining rings (DIN 472 for 16 mm holes). I used i prior version of this model without the rings as upper printhead bearing and it works quite well, improving the print quality significantly compared to the single bearing version. The y-Stepper gets a bit warmer, but i did not have any missed steps yet, using the tmc2208 drivers.
Update 29.06.18: I changed the inside diameter of the Mono-Version to 16,05 mm, just like the dual version and uploaded this part as new file, called "...1605".
Update 14.02.19: Added a ring secured version of the single bearing holder