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 6130-01-253-2104
NSN 6650-00-390-3568
NSN 5930-00-621-7818
NSN 5996-01-418-5140
NSN 6320-01-229-2264
NSN 5855-01-274-2307
NSN 6645-00-296-8310
NSN 6110-00-108-6478
NSN 5855-01-381-6052
NSN 5998-00-293-6286
NSN 5835-00-034-4976
NSN 5998-01-564-7879