This is a remix of http://www.thingiverse.com/thing:1172838 and http://www.thingiverse.com/thing:102482
I wanted to use both together and instead of printing each on it's own, I put both together - edited the bearing to fit into the block on it's full lenght and voila - finished bearing block with the bearing of my choise already fitted into the block. It fits perfectly on the 8mm rods of my Anet A8.
printer: Anet A8 (customized)
infill: 30% (fast honeycomb)
wall layers: 4
top and bottom layers: 3
print time: ~40min
At the beginning the bearings are really tight but the rod fits into them. I just used the sharp edge of the rod to remove just a tiny amount of material until the rod moves freely but still stable and without noise throug the bearings.
You are still able to use a drill, but do this on low speeds and check often to not overdo the removal of material.