Product Description
This is an ultra-precision tilting table for a large-field interferometer. Both the upper and lower plates are made from high-grade hardened steel. The upper surface is precision lapped and is eight inches in diameter. There are concentric milled grooves in the upper plate.
The upper plate rests in a precision ground cup bearing machined into the lower support plate. A pair of knobs situated at right angles to each other act on the cup bearing flange which is pressed against the screw bearing surfaces via strong compression spring cylinders located opposite the screws. The threads are 100 TPI allowing extraordinary tilting accuracy and sensitivity.
Furthermore, a second set of knobs act in a similar manner on a hardened steel boss located in the base of the lower plate. The boss has three counterbored screw holes and was obviously fixed to a flat jig plate or granite baseplate. When this is secured to such a base the entire fixture can be rotated about the center boss (it too is precision ground). The second set of knobs allows the axis of rotation to be centered. One of the two knobs is broken off flush with the brass bearing insert and will need to be repaired in order to restore that functionality. This adjustment would be useful to prevent the central fringe from shifting as the table is tilted but the table will work without it.
Other than the broken knob this fixture is in superb condition - there are no scratches or bumps in the surface of the plate. There is a bit of discoloration about one of the grooves, but that is about it. There is no indication as to the manufacturer, but it is of extraordinary quality - perhaps Hilger & Watts.
Item is being sold as is. Please see photo for details.
Photo set 1668