A wiggler, edge-finder, or center-finder is a tool used in the spindle of a machine such as a mill. The device is used to accurately determine edges or markings and therefore the center of a workpiece or a previously machined feature during the set-up phase of a machining operation.
A rotating tool, meaning the machine spindle must be turning for the tool to work. On one edge a cylinder shape is spring loaded, when the edge finder touches an edge a kickoff of this cylinder is noticed. On the other end a cone shape is also spring loaded and is used to locate the center of a previously drilled hole. Most accurate of all edge finders. Improved accuracy is obtained by use of collet. Repeatable to 0.0002″ or better.
Electronic edge finder
Sometimes also referred as a digital edge finder, this instrument can locate edges of work pieces and also height offsets. It works in a non-rotating spindle, which is a great advantage over its mechanical counterparts. It is battery operated and works by lighting up its internal LED (usually red) when the electrical circuit formed by the instrument and the machine is closed. The light is visible through openings in the case. A repeatability of 0.001″ is obtained.
A pencil like tool used to locate markings on stock. In difference with the edge finder, the tip is not spring loaded and it works with the spindle stopped. Sometimes a magnifying glass is used to assist in marking location. Only as accurate as the lines that are drawn on the part.
This information originally retrieved from http://en.wikipedia.org/wiki/Wiggler_(tool)
on Monday 17th October 2011 6:57 pm EDT
Now edited and maintained by ManufacturingET.org