Abstract: A thimble 61 formed with graduations 65 and numerals 67 on the outer circumference thereof at predetermined intervals is molded by double-color molding using two kinds of resin 62, 63 with different colors. After a molding product having the graduations 65 protruding outwardly on the outer circumference of a base tube 64 is formed of the resin 62, an outer skin 66 covering the outside of the base tube 64 except for the graduations 65 is formed of the resin 63. Thereafter, the numerals 67 is formed on the outer skin 66 by means of laser marking. Similarly, an outer sleeve is formed with graduations and numerals on the outer circumferential surface along the axial direction at predetermined intervals.

Abstract: A micrometer includes a main body holding an anvil at one end portion and a spindle at the other end portion through an inner sleeve is formed with a frame which is made by placing a pair of frame elements, which are formed by bending metal plates, one upon the other to reduce weight while ensuring rigidity. The outside of the frame is covered with resin to reduce the weight, enhance the rigidity, and prevent the influence caused by the heat of hand when the frame is gripped.

Abstract: A thimble 61 formed with graduations 65 and numerals 67 on the outer circumference thereof at predetermined intervals is molded by double-color molding using two kinds of resin 62, 63 with different colors. After a molding product having the graduations 65 protruding outwardly on the outer circumference of a base tube 64 is formed of the resin 62, an outer skin 66 covering the outside of the base tube 64 except for the graduations 65 is formed of the resin 63. Thereafter, the numerals 67 is formed on the outer skin 66 by means of laser marking. Similarly, an outer sleeve is formed with graduations and numerals on the outer circumferential surface along the axial direction at predetermined intervals.

Abstract: The invention is constituted such that a tubular cavity is formed in the arm of a frame which movably supports the spindle; said cavity houses an index scale and a slit disc; and thereby the measured results can be read as an electric signal without affecting the function of the micrometer, said index scale and said slit disc being located coaxial with the spindle.

Abstract: A measuring instrument with two feeds for its spindle. A first sleeve is keyed to a second sleeve so the sleeves can move axially relative to each other but cannot rotate relative to each other. A spindle is threaded into the second sleeve and moves axially when its thimble is rotated to provide the first feed. A second thimble has a first thread engaging a thread of the first sleeve and a second thread engaging a thread of the second sleeve. Rotation of the second thimble moves the second sleeve and spindle axially to provide the second feed. The first and second threads can be selected to provide a fine feed or a coarse feed of the second sleeve and spindle.