Civil Engineering Reference
In-Depth Information
Fig. 5.5. The wiggler type of edge finder has been in use for many years. It has
largely been superseded by the edge finder type.
Wiggler
For many years, the most common edge finder was the wobbler or wiggler
type. (This was so called as after it was used to find the edge of a component,
it rolled along the edge of the work and wandered off.) The wiggler usually
came as a kit with several different ends. The main body accepted the various
ends which fitted into a ball-shaped depression in the body, which could usu-
ally be adjusted for a friction fit. The usual accessories were a ball, a parallel
cylinder, a point for centre finding and an adaptor to take a lever dial test in-
dicator. The ball is for finding the edge of a square piece of work, while the
cylinder is used for finding the edge of a round bar. The point is used to find
the intersection of two lines scribed onto the workpiece surface. This type of
edge finder works well; I used one for many years, but eventually I moved on
to the edge-finder or centre-finder type.
Using the edge finder
The edge finder consists of a parallel shank with a cylindrical or top hat
shaped end that is held onto the shank with a spring. While the shank is run-
ning, bring the edge finder towards the job so the end starts to run true the
closer it comes to the edge of the work. When it reaches the workpiece's
edge, the end will roll along the edge of the work indicating that the edge has
been found. The edge finder end must be square to the work or it will not give
a true indication. This type of edge finder is also suitable for finding the edge
of a round bar.
