chris_n wrote:are you guys using the 50hz version on 60hz power? this results in the motor spinning at a higher rpm when run on 60hz.
if this is the case, using a converter and running it at 50hz helped with the fines at the end of grinding, but did not eliminate them completely. so perhaps it's due to the higher RPM?
I was wondering that too, but the OP is in Europe (50Hz). Depending on the type of AC motor used, running a 50Hz motor at 60Hz will increase motor speed by 20%, regardless of voltage. (The change in rpm that happens with voltage is due to different reasons.)
However, as Japan has 50Hz and 60Hz regions, there may be different versions of the grinder. I know that the Fuji R-440 is available in 50Hz and 60Hz versions, but I do not know about the R-220.
If the burrs in the Fuji behave like the burrs in the Apex, then increasing RPM might increase fines - this happens in my Apex going from 400rpm to 500rpm.