Measure the overall flatness of your surface plate.
SHOP PLANEKATOR KITS
The Planekator measures the overall flatness of your surface plate. It enables you to take direct indicator readings of your surface plate with autocollimator-accuracy, but without the complicated mathematics of the autocollimator. When used in conjunction with a Starrett Repeat Reading Gage, you'll have a very accurate idea of the flatness of your surface plate.
Each kit includes a precision granite straight edge, one adjustable support, one fixed support, a certified 0.00002" dial indicator and an indicator carriage. The entire kit is shipped in a heavy-duty travel case. The straight edge comes equipped with lifting handles, correction tape indicating the accuracy at 1" intervals, and includes a NIST-traceable certificate that meets ISO/IEC 17025 requirements.
The Planekator straight edge should be at least equal to the full width, and at least equal to 50% of the length of the largest surface you will be inspecting. For example, a 36" planekator straight edge can be used to calibrate any surface up to 36" x 72".