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 5945-00-986-3890
NSN 6105-00-111-7327
NSN 5990-00-826-7928
NSN 5855-00-484-8638
NSN 6620-00-185-1671
NSN 6645-01-113-6712
NSN 6135-01-633-8502
NSN 5999-00-615-3931
NSN 6110-00-601-2985
NSN 5960-01-118-3394
NSN 6110-01-056-4964
NSN 5855-01-351-8909