Lot #158: Microflat Precision Granite Surface Plate

This is a Collins Microflat Granite Surface Plate. While it might look like a simple block of stone, it is actually a high-precision tool used in machining, engineering, and quality control. A surface plate provides an extremely flat, stable reference plane for inspecting parts and performing precise measurements. It is made from solid granite (likely "Black Diabase"). Granite is preferred over metal because it is temperature-stable, non-magnetic, and does not "burr" if scratched. These plates are lapped to incredible tolerances, often within millionths of an inch of being perfectly flat across the entire surface. Surface measures 24” x 18” and 4” tall. THE ESTIMATED WEIGHT IS BETWEEN 180 and 210 POUNDS. Bring appropriate vehicle and help to move. Bring packing material. Pickup category timeslot {A}