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 6110-01-467-2227
NSN 7035-01-013-9889
NSN 5905-01-099-9496
NSN 5945-01-152-7539
NSN 5996-01-646-2851
NSN 5998-01-222-9568
NSN 6620-01-274-3423
NSN 6620-00-361-3590
NSN 5935-00-316-9410
NSN 6650-00-575-7487
NSN 6105-01-418-9336
NSN 6240-01-277-7962