axially spaced from the large diameter end of the tapered shank 42 and from each other as shown in fig6 the grooves are defined by three flanges 43 44 and 45 the uppermost flange 43 is also a gear and engages with a gear drive mechanism in spindle 36 the tool holders are held in tool storage magazine 14 in the vertical position by engagement into slots in carrier plate 15 fig1 in the upper of the two grooves of the tool holder fig7 and 8 are a top cut away view and a cross sectional view respectively of tool storage magazine 14 showing a portion of carrier plate 15 with a tool holder 40 positioned in one of slots 17 and being supported in its upper groove between flanges 43 and 44 generally for use with the automatic tool changer of this invention tool storage magazine 14 is a rotatable circular covered assembly holding from 12 to 25 tools in separate peripheral tool holder holding slots located in carrier plate 15 mounted on a turntable 16 a suitable mechanism and control means is used to index the tool storage slot to a singular specified tool engaging position a rotor base 46 and control cabinet 47 is shown in fig1 and fig2 each of the tools is position indexed in the tool storage magazine 14 that is a given tool is removed from a slot of tool storage magazine 14 for use in milling machine 10 and is subsequently returned.