Vertical or horizontal projection. Most U.S.-made optical comparators feature a horizontal projection axis, i.e., the light path from the illuminator to the part is horizontal, entering at the front of the machine. Vertical projection machines are an alternative, depending on the type of parts you're measuring Horizontal projection is best suited for larger, heavier parts that can be easily placed in a fixture. Comparators are provided with a worktable assembly for motion along the x and y axes. They are available in different sizes, resolutions, and load capacities.
Motorized worktables are convenient and helpful for both repetitive and automated inspections.
Helix motion, accomplished by pivoting the worktable about the y axis, is useful for thread measurement, as it allows a true profile of the thread form to be imaged. Electronic digital readout. The level of DRO you choose depends on the level of computational power you need. Using a DRO requires entering x-y coordinate points into a function, which then returns the calculated geometry and associated values. Typical measurement routines include angle, radius, diameter, intersection, and included angle.