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 5999-00-010-1768
NSN 5945-01-406-3200
NSN 7035-01-253-2868
NSN 7035-01-570-3831
NSN 6320-00-731-6134
NSN 6645-01-633-1852
NSN 6685-01-381-0759
NSN 4140-00-430-5155
NSN 6645-01-597-2222
NSN 5925-01-067-2928
NSN 6645-01-253-6023
NSN 5835-01-111-0969