Lens Clock

MEASURING BASE CURVE WITH THE VIGOR 35.216 LENS CLOCK


 A LENS CLOCK HAS THREE PINS, WHICH WHEN PRESSED AGAINST A LENS READ OUT A DIOPTIC VALUE.

 THE TWO END PINS ARE STATIONARY, WHILE THE CENTER PIN RIDES UP AND DOWN TO GAUGE THE DEGREE OF CURVATURE.

 A NEEDLE ON THE FACE OF THE CLOCK POINTS TO THE DI OPTIC CURVE OF THE SURFACE BEING MEASURED.

 EACH STOP ALONG THE DIAL IS CALIBRATED IN BOTH RED AND BLACK NUMBERS.

 IF THE CURVE BEING MEASURED IS ON THE FRONT SURFACE OF THE LENS, THE BLACK NUMBERS APPLY; IF IT IS ON THE BACK SURFACE, THE RED NUMBERS APPLY.

 A LENS CLOCK IS IN PRECISE ADJUSTMENT IF WHEN PRESSED AGAINST A PERFECTLY FLAT HARD SURFACE, IT READS ZERO.