Ride-On Grinders :: Surface Preparation - DraygonDraygon produces the only sole-purpose, tier four propane or electric ride-on concrete grinder/polisher. This machine can be switched from wet to HEPA dry.ride on grinding machines,Ride On Concrete GrinderJan 30, 2014 . Ride On Concrete Grinder. . 8:56. Grinding down high spots on concrete - Duration: 1:33. WerkMaster Grinders & Sanders Inc. 33,633 views.