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 6650-01-577-1784
NSN 5935-00-319-4788
NSN 6620-01-046-8623
NSN 5905-01-067-0024
NSN 5960-01-577-5682
NSN 6650-01-479-9024
NSN 6645-00-285-8781
NSN 5935-01-288-9200
NSN 5975-00-855-4623
NSN 6105-01-618-3881
NSN 5998-00-209-9077
NSN 6145-00-147-5440