Rahn Planekator Highlights
Federal Spec GGG-P-463c dictates that the proper methods for determining the overall flatness of a granite surface plate. In section 4.5.9, it states, "Aƒsystem of diagonals, perimeter and center lines may be calibrated on plates, and especially on small ones, by using a precision calibrated straight edge, adjustable supports and a suitably mounted indicatorƒ". This is a basic description of the Planekator.
The Planekator kits consist of a granite straight edge, a set of supports (one fixed height and one adjustable), a calibrated .000020" dial indicator with indicator carriage and a storage case. The straight edge is supplied with a correction tape.
When selecting your Planekator, consider the size of the plate(s) you will be inspecting. The straight edge should be at least equal to the full width of the plate and at least equal to 50% of the length of the plate. For example, a 36" Planekator straight edge can be used to calibrate any surface up to 36"x72".
- For checking flatness of a surface place. Consists of an Autocollimator-calibrated diabase straight edge, adjustable supports and an indicator base