|1.Measure the crown under the bridge beside each rib wherever possible.
2.Record data before and after stringing piano.
- The rest position (fully extended, which reads o.ooo”) of the dial gauge extends from the aluminum bar by 1” (1.000”)
- The Crownulator will therefore read a flat surface as 1.000”
- Any deflection will be the difference of 1.000” and the gage reading. A reading of .966” for example represents a deflection of .034” (1.000-.9.66=.034)
3.The radius in feet can be determined from the following formula:
Where: H = arc deflection and C = span of Crownulator
Where the span of the Crownulator = 12”, 1/4C = 36
Thus, a reading of .034 represents a radius in feet of:
Each span is slightly different as a result of milling the stock square at the edges. You should therefore measure the span of your Crownulator and recalculate for the constant (1/4C²). You can then make a chart of readily available values or email with your exact span length and we will provide you with a chart.