1792 W. Marshall Minutes in (1796) II. 325 This pathlet was formed with the frame level in hand.
1875 E. H. Knight II. 913/1 Frame-level, a mason's level.
1904 21 Jan. 5/1–2 (advt.) Machinist iron frame levels.
2003 R. T. Kreh (ed. 5) ii. vi. 56/2 High-quality aluminum milled frame levels that are very comfortable to handle even in cold weather.