Starrett - Inside Micrometers

The Starrett Combination Head for inside micrometers combines the precision of a dial indicator sensor and the linear accuracy of a micrometer. This combination of indicator and micrometer reduces the need for operation "feel" and provides faster readings with increased reliability.

This head is interchangeable with the Starrett No. 128 Series End Rods and extension combinations.

For direct measurements, the dial indicator hand and the telltale hand must both register zero before reading the micrometer. As a comparator, the micrometer is first set to the nominal dimension and ± deviation from zero is read from the dial indicator. The gage should be rocked to obtain a minimum reading on the indicator. Out-of-roundness can also be checked – any variation being shown by the indicator.

For Inch-reading tools, the head can be adjusted within a range of 2". It extends the overall range by an additional 5". The special No. 81-138J jeweled non-shock indicator is graduated .0005", range ± .040" and reads 0-40 on both the plus and minus dials.

For millimeter-reading tools, the head can be adjusted within a range of 50 mm. This extends the overall range an additional 125 mm. The special No. 81-181J jeweled non-shock indicator is graduated 0.01 mm, range ± 1 mm and reads 0-100 mm on both the plus and minus dials.

The 10" (250 mm) master should be used vertically with the shoulder on the indicator end of the head, seated squarely, as shown in photo.

Combination Head with Inside Micrometer
No. 128

J.W. Donchin Co.
Ph: 773-261-2182 • Fax: 773-261-2867 • Email: sales@jwdonchin.com