Picked up a small CNC mill with balls screws for cheap. Travel is pretty limited at about 6" x 4" but otherwise it looks fairly stiff and has servo drives. Looks to be metric and has a Yuasa tag but haven't been able to find any docs on it online. It has been sitting a while and don't know the history. When I turned the ball screws by hand they were a little crunchy. Not sure if they are binding from lack of lube or if there is crud in the ball nut. Things look pretty clean so I am hoping it's just lack of lube. Haven't done anything else yet. Should I apply some lube and see if things free up or should I take things apart? Haven't messed with ball screws before.