The Hembrug U2 was a copy of the Cincinati grinder but among others the spindle head is contructed different. The cincinati has a split bearing holder and the Hembrug has the bearing holder as one piece. This makes them more solid.

The older spindletypes came in two versions, v-belt and flatbelt. The flat beld runs smoother but the v belt can transfer more power. This older spindletype runs in two double rollerbearings and a double set of axial thrust bearings. It turned out that the axial thrust bearings were not very capable of doing the job.

The spindle was redesigned with one set of double roller bearings and a matched pair of angular thrust bearings.

Another common problem was the steel cage on the first roller bearings. There were chips breaking of the cage and ruining the surface of the bearing.
Furthermore there were some machines that showed distortion in the head. The bearing holding surfaces wear not in line and the rollers starting to run at the outside. This lead to broken bearings quite some times.