An expansion of the LM8UU idler
can easily be pushed to the idler on the same axis.
The axis height can be adjusted
with a screw.
Extra parts you need:
1x M4 screw < =32mm
1x M4 nut
1x M3 screw 17mm
1x M3 nut
2x M2 screw 8mm or glue
Insert the -tip- of the m4 nut first!
The real photo shows a "beta" version.