This grinder arbor adaptor is machined from a sold steel stock rod that allows you to convert your grinder arbors from a M10 x 1.5 arbor to an 5/8"-11 threaded arbor spindle. This grinder arbor adaptor is machined from a sold steel stock rod that allows you to convert your grinder arbors from a M10 x 1.5 arbor to an 5/8"-11 threaded arbor spindle.