An optimal machine tool microscope for center alignment of the cutter axis and a reference point on the surface of the workpiece material for jig boring machines, milling machines and the like. Center alignment can be performed quickly and accurately. It is placed on the machine tool main shaft (cutter spindle), and while looking through the eyepiece, a reference point on the surface of the material is aligned to the center of an index visible within the field of vision, enabling center alignment to be performed easily and accurately. * The optical axis and taper axis of the eyepiece mount is 65° ; comes standard with any one of National tapers Nos. 30 and 40 and Morse tapers Nos. 3, 4 and 5. *: If the use of a shank other than a standard taper shank is desired, please provide a shank that can be installed with this instrument and we will adjust the optical axis to fit the shank. Please use caution, as once installed in this instrument, a shank cannot be changed afterward. *: The National taper is for general milling machine use. Please consult us when installing in a machining center.