Feeler lever

The feeler arm is a measuring tool that is used to examine cylindrical and conical bodies in order to determine to what extent they deviate from the circular shape in cross-section .

The feeler lever consists of a short, steel lever , one end of which is smoothly rounded and finely polished, and the other end of which is provided with an upward extension made of brass that is 50 to 100 times the size of the small lever. By slowly turning the test object around its own axis, e.g. B. on a lathe , and pushes the short lever arm until it touches the object, the long lever arm serving as a pointer on an arc of degrees will give a deflection every time the cross-section of the test object deviates from the circular shape.

If you move the instrument parallel to or at an angle to the axis of the workpiece, you can also check its cylindricity or conicity. In this way, very small inaccuracies that could not be detected in any other way are displayed, such as B. is necessary for mathematical instruments.