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 5925-00-142-9991
NSN 5915-00-141-0410
NSN 5996-00-250-6556
NSN 6110-00-991-8637
NSN 6220-00-899-4273
NSN 5965-01-208-1532
NSN 6150-01-194-8319
NSN 5999-01-504-9067
NSN 5965-01-657-4519
NSN 5965-00-698-0433
NSN 5999-00-717-7498
NSN 5930-01-214-5327