Introduction

A paper micrometer is a small measuring instrument used to measure the thickness of a piece of paper. The micrometer, roughly twice as large as a regular stapler (see Figure1), weighs eight pounds. It has four main parts: the frame, the dial, the hand lever, and the piston.

The Frame

The frame of the paper micrometer is a cast piece of steel that provides a surface to which all the other parts are attached. The 5 1/8 inches high and 7 1/2 inches long frame, painted gray, looks like the letter C with a large flat disk on the bottom and a round calibrated dial on top. Excluding the bottom disk, the frame is approximately 1 1/4 inches wide. The disk is 41/2 inches in diameter and resembles a flat hockey puck.

The Dial

The dial shows the thickness of the paper. The dial looks like a round watch dial except that it has only one moving hand. The frame around the dial is made of chrome-plated metal. A piece of glass protects the face of the dial in the same way that the glass crystal on a watch protects the face and hands. The dial, 6 inches in diameter and 7/8 inch thick, is calibrated in .001-inch marks, and the face of the dial is numbered every .010 inch. The chrome-plated metal hand is made from a .4-inch thin, stiff metal rod, 3 inches long and pointed on the end.

The Hand Lever

The hand lever, shaped like the handle on a pair of pliers, raises and lowers the piston. It is made of chrome-plated steel and attaches to the frame near the base of the dial. The hand lever is 4 inches long, 1/2 inch wide, and 1/4 inch thick. When the hand lever is depressed, the piston moves up, and the hand on the dial rotates. When the hand lever is released and a piece of paper is positioned under the piston, the dial shows the thickness of the paper.

The Piston

The piston is a rod that moves up and down when the operator depresses and releases the hand lever. This action causes the paper's thickness to register on the dial. The piston is 3/8 inch in diameter, flat on the bottom, and made of unfinished metal. The piston, which slides in a hole in the frame, can measure the thickness of paper up to .300 inch.

Conclusion

The paper micrometer is an indispensable piece of equipment in a printing shop or office where paper is used in large amounts. The thicker the paper, the more expensive it is to purchase or mail in bulk. It is also an instrument used in science laboratories and industries where coatings are applied to paper. The cost of a paper micrometer can range from under $100 to several thousand depending upon whether it is a simple mechanical type or a more complex, electronic variety.