Measurements are taken by comparison so some type of set master should be used as a reference standard. We recommend setting as close to the hole being measured as possible, and this can be easily done with gauge blocks or with a micrometer Complete Set, Range.0001 Grad with Case with a micrometer. The item "Starrett 81-111630 complete Dial Bore Gauge complete set" is in sale since Sunday, January 27, 2019. This item is in the category "Business & Industrial\CNC, Metalworking & Manufacturing\Metalworking Tools\Metalworking Inspection & Measurement\Indicators". The seller is "1dave680" and is located in Southaven, Mississippi. This item can be shipped to United States.