Conventional Knee Mill Machines / Vertical Knee Mills "Willis Machinery" offers five different models of vertical knee mills both conventional and CNC. Our mill machines range from the model WM3VS 3 horsepower (3HP) variable speed R8 spindle mill machine with a 9 inch x 49 inch table to a massive 5 horsepower (5HP) 40 taper spindle Series II style machine with a 12 inch x 59 inch table ...