The Starrett 133MB 375 mm Engineers' and Plumbers' spirit level has one level and one plumb vial for determining horizontal and vertical plane, and an adjustable incline level that indicates the degree of incline in 1mm per 250mm graduations, reading up to 40 mm per 250 mm of incline. The vials are made of glass to resist scratching and provide clear readings, and have a sensitivity of 17 to 21 minutes. Level and incline can be read from the side and the top. A V-shaped groove along the base provides reliable seating when leveling round items such as pipe, conduit, and shafts. The level has a cast iron frame for durability and precision-machined leveling surfaces for accuracy. Levels are used in the building trades, engineering, surveying, and metalworking, among other applications.
Levels are instruments that are used to determine the true horizontal or vertical plane of a surface. The most common type of level is the spirit level, or bubble level. Spirit levels have a liquid-filled, bowed tube (also called a vial) with a bubble that moves when slight adjustments are made to the level. When the bubble settles between marked points on the vial, it indicates that a surface is horizontally or vertically straight. Levels can have one or more vials to determine the horizontal plane, the vertical plane, or various points between, such as a 45-degree angle, simultaneously. Some levels include a laser line indicator that projects a horizontal or vertical beam on a surface. Bullseye levels, or surface levels, are circular, flat-bottomed spirit levels that determine whether a surface plane is level. Machinists’ levels are made of metal and have surfaces designed specifically for rugged use in a machine shop or tool room. Levels can range from highly-complex and accurate machines, such as those used in the surveying and construction industry, to precision instruments used in carpentry and other building trades, to simple, pocket-sized devices for do-it-yourself projects.
The L.S. Starrett Company manufactures precision measuring tools, metrology and testing equipment, and saw blade products. The company, founded in 1880, is headquartered in Athol, MA.