GARDNER LAB

GARDNER LAB INC. NEEDLE THICKNESS GAGE ENCLOSED IN HARD SIDE CARRYING CASE WITH BLUE VELVET INTERIOR. INCLUDES: CAST ALUMINUM METER WITH WITH 4 SPARE PINS METAL BLOCK SUBSTRATE ON BOARD LAMP WITH 2 SPARE LAMP BULBS AND CONNECTING CORD. ALSO INCLUDES TOOLS FOR CHANGING PINS AND ADJUSTING. THIS INSTRUMENT IS DESIGNED TO MEASURE THE THICKNESS OF ELECTRICALLY NON-CONDUCTING FILMS ON METAL (CONDUCTING) SUBSTRATES. IT IS SMALL ENOUGH TO BE USED IN THE FIELD WHERE THE SUBSTRATE CAN BE MADE PART OF THE ELECTRICAL CURRENT. THE NEEDLE MAKES ONLY A MINUTE PUNCTURE IN THE FILM. IN MANY INSTANCES PARTICULARLY IN A GO NO GO DETERMINATION THE DAMAGE IS SO SLIGHT THAT THE METHOD MAY BE CONSIDERED NONDESTRUCTIVE FOR MANY END USES. THE CAST ALUMINUM HOUSING CONTAINS THE NEEDLE SCREWS FOR FORCING THE NEEDLE THROUGH THE FILM AND A LAMP TO SIGNAL WHEN THE NEEDLE CONTACTS THE SUBSTRATE. FOR USE IN THE FIELD AND FOR OCCASIONAL USE IN THE LABORATORY. THE ELECTRIC CIRCUIT COMPRISES THE NEEDLE THE SUBSTRATE A DRY CELL THE LAMP AND A CORD THAT CONNECTS WITH THE SUBSTRATE. IN THE LABORATORY. IF MANY MEASUREMENTS ARE TO BE MADE IT IS ADVISABLE TO USE A STEP DOWN TRANSFORMER AND CONNECT TO 110 VOLT SOURCE. THE THICKNESS IS READ ON THE DIAL. ATTACHED TO THE SCREW. ONE TURN OF THE DIAL RAISES OR LOWERS THE NEEDLE BY 2 MILS. THE DIAL IS GRADUATED IN STEPS OF 0.5 MILS. RANGE IS 0 TO 15 MILS. THE ZERO SETTING OF THE NEEDLE IS OBTAINED BY RETRACTING THE NEEDLE WITHIN THE HOUSING PLACING THE GAUGE ON A PLAIN METAL BLOCK AND LOWERING THE NEEDLE UNTIL THE LAMP SIGNALS CONTACT. THE BLOCK IS REPLACED BY THE SPECIMEN AND THE NEEDLE IS LOWERED AGAIN UNTIL THE LAMP SIGNALS CONTACT THE DIFFERENCE BETWEEN THE 2 READINGS IS THE THICKNESS OF THE FILM. THIS METHOD HAS BEEN STANDARDIZED BY ASTM AS PROCEDURE B IN METHOD D 1400 MEASUREMENTS OF DRY FILM THICKNESS OF NONMETALLIC COATINGS OF PAINT VARNISH LACQUER AND RELATED PRODUCTS APPLIED ON A NONMAGNETIC BASE.