A precisely calibrated instrument used as a master reference standard to establish an absolute horizontal plane. The metal base is seasoned and heat treated or otherwise specially treated to insure maximum stability, and is accurately machined and scraped to the true plane on the contact surface. The top plate is of nonconductive heat insulating material. It has a very sensitive vial graduated to indicate a variation of 0.0005 inch (0.0127 mm) per foot (0.3048 m) in a horizontal plane. It may have a cross level vial to assist in setting the true horizontal by showing position laterally.
Classification: Other measuring or checking instruments, appliances and machines, nesoi in chapter 90
NSN 5935-01-365-0677
NSN 5998-01-322-4648
NSN 6220-00-146-3226
NSN 2925-01-110-1467
NSN 6320-01-600-5808
NSN 5910-01-485-8128
NSN 5990-00-202-5127
NSN 6220-01-047-0009
NSN 5935-01-245-2181
NSN 5960-01-123-8775
NSN 5950-01-287-3860
NSN 6650-01-125-4989