This article may be confusing or unclear to readers. In particular, differentiate the types (edge/center) of tool. Define kickoff and collet. Further explain the context and usage of the tool - is it moved across the work or pressed down against it? What does an operator observe or manipulate? How does a collet help accuracy? What constitutes a proper setup or an improper one? Explain why digital is erroneous. Are the repeatabilities dependent on the quality of the tool, operator, both, or neither? How is a center finder different than a school pencil?. (May 2017) (Learn how and when to remove this template message)
A wiggler, wobbler, edge-finder, center-finder or laser-centering-device is a tool used in or on a machine like a mill, to accurately align the machining tool with the work piece center, work piece edges, layout markings, or previously machined feature during the set-up phase of a machining or other 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. This style of edge finder is considered to be the most accurate, and its accuracy can be further improved through the use of a collet. In proper setups, a repeatability of 0.0002 in (0.0051 mm) or better can be obtained.
Electronic edge finder
Sometimes also (erroneously) 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, the workpiece and the machine is closed. The light is thus illuminated when the edge finder is touching the workpiece and is visible through openings in the case. A repeatability of 0.001 in (0.025 mm) can be obtained.
A tool used to align the machining center to specific locations on stock or work pieces. Often these locations might be marked using layout method (bluing the surface and scribing a precise location with the intersection of the two lines identifying the position to be machined, etc. Sometimes a magnifying glass is used to assist in marking the location. One drawback of this method is that it is only as accurate as the lines that are drawn on the part.). In contrast to the edge finder, in the mechanical versions, the tip is not spring-loaded, and it works with the spindle stopped. In laser versions, an 'X' of light is often projected from the machining center onto the work piece and the work piece location is adjusted to align with the intersection of these lines. In contrast to centering devices, the center finder cannot directly find the center of a work piece, thus requires additional calculation, measurement and/or layout method to align to.
A tool used to accurately adjust and align the center plane or axis of a work piece or work piece feature to the machining center. In contrast to the edge finder, it most often requires no calculation, measurements or layout method markings to allow this alignment. Mechanical versions may work with the spindle stopped. Laser centering devices can be used to cast patterns of light which, depending on angle of the laser, can achieve a high degree of precision.
- Using an edge finder (video)
- Wiggler usage
- This shows you how to use a wiggler to center a rotary table.
- Laser Centering Device (video)