grinding motion

• rotatingTurning on an axis
• circularForming a closed curve
• abrasiveRough enough to erode
• frictionResistance between touching surfaces
• gratingCrossed bars or harsh

scraping · crushing · pulverizing · milling · polishing · sanding · teeth · coffee · pepper · mortar · pestle · wheel · grit · coarse · smooth · wearing · erosion · rhythmic