Fractional-decimal vernier

A rule for measuring a distance accurately to eighths of an inch precision directly on said rule and a first vernier for measuring said distance accurately to five-thousandths of an inch precision on said first vernier, comprising in combination:

• a zero point on said rule representing a magnitude of said distance equal to zero;
• one-eighth inch graduations on said rule extending from said zero point and representing increasing distance from said zero point;
• and
• twenty-five equally spaced graduations within a three inch space on said vernier, beginning with a first one of said twenty-five graduations located in a first proximity to said zero measuring point, a remaining twenty-four of said twenty-five graduations more remote than said first proximity relative to said zero measuring point,
• wherein said twenty-five vernier graduations may be compared with said one-eighth inch graduations on said rule for correspondence therebetween;
• whereby when a second one of said twenty-five vernier graduations is more closely aligned with a first one of said one-eighth inch graduations than any other of said twenty-five vernier graduations to other ones of said one-eighth inch graduations, the relative position of said second one of said twenty-five graduations relative to said first one of said twenty five graduations may be multiplied by five thousandths of an inch, and the result subsequently added to a one-eighth inch fractional distance measurement from said zero point which has been converted to decimal format, to thereby calculate a measurement with five-thousandths of an inch precision, without interpolation.

A method of measuring a first distance between a first point and a second point with a fractionally graduated rule having a whole unit scale and primary fractional graduations dividing said whole units by multiples of two into halves, quarters and eighths and converting said distance measurement into a decimal distance measurement dividing said whole unit scale into tenths, hundredths and thousandths, comprising the steps of:

• aligning a first measuring structure coupled to said fractional rule with said first point;
• moving a block, carrying a zero-point marker and a vernier having vernier graduations therewith, relative to said fractional rule to align a second measuring structure to said second point;
• calculating the smallest fractional distance between a zero measurement position on said fractional rule and said zero-point marker on said block, whereby when said first and said second point are in the same physical position, said zero-point marker aligns with said zero measurement position on said fractional rule;
• converting said smallest fractional distance to a first decimal value;
• identifying a most closely spaced vernier graduation to a fractional graduation;
• multiplying by a decimal amount the number of vernier graduations said most closely spaced vernier graduation is from said zero point marker to produce a second decimal value;
• and
• adding said first decimal value and said second decimal value together to produce a sum equal to said decimal distance measurement.