Inside Micrometers 128 Combina tion Head with Inside Micrometer The 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 operator "feel" and provides faster readings with increased reliability. This head is interchangeable with the 128 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 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 50mm. This extends the overall range an additional 125mm. The special 81-181J Jeweled Non-Shock Indicator is graduated 0.01mm, range ±1mm and reads 0-100mm on both the plus and minus dials. All inside micrometer masters should be used vertically with the shoulder on the indicator end of the head, seated squarely. 128 Sets 6-294"/150-7350MM Each set consists of a satin- chrome micrometer head which can be used in combination with any one or more of a series of rigid, tubular steel measuring rods to obtain the required length. The micrometer head is a modification of our 63, which has a 2" (50mm) range. The head has a basic length of 4" (100mm) which can be lengthened to 6" (150mm) by means of its measuring range. Besides those listed on the lead page of this section, the 128 Sets have these additional features: • For inside measurements from 6-294" (150-7350mm) (longer sizes are also available on special order) • Interchangeable tubular steel measuring rods and extension rods are lightweight with extreme rigidity. Rods screw into each other and seat against hardened ground and lapped surfaces necessary for high accuracy. Rod diameter 5/8" (16mm). • Rods are provided with insulated handles to minimize expansion from hand heat. All rods marked with length • All rod anvil contacts are hardened and ground • All measuring rod anvil contacts are adjustable (plain extension rods are not adjustable) • Adjustable, ground steel supporting collars (placed in "V" grooves when used in the horizontal position) 128 and 128M Combination Head with Inside Micrometer Sets Cat. No. EDP Description 128 64381 Inch-reading combination head with setting master 128M 68117 Millimeter-reading combination head with setting master 128 and 128M Micrometer Head Sets Cat. No. EDP Range with Micrometer Head Movement of Screw Grad. Description Range with Combination Head 128AZ 64375 6-78" 2" .001" With (1) 4-6" head, (1) each 2", 4", 6", 8", 10", 12" rods, (1) 12" ext., (2) 24" ext. 11-83" 128BZ 64376 6-150" 2" .001" With (1) 4-6" head, (1) each 2", 4", 6", 8", 10", 12" rods, (1) 12" ext., (5) 24" ext. 11-155" 128CZ 64377 6-294" 2" .001" With (1) 4-6" Head, (1) each 2", 4", 6", 8", 10", 12" rods, (1) 12" ext., (11) 24" ext. 11-299" 128MAZ 64378 150-1950mm 50mm 0.01mm With (1) 100-150mm head, (1) ea. 50, 100, 150, 200, 250, 300mm rods, (1) 300mm ext., (2) 600mm ext. 300-2100mm 128MBZ 64379 150-3750mm 50mm 0.01mm With (1) 100-150mm head, (1) ea. 50, 100, 150, 200, 250, 300mm rods, (1) 300mm ext., (5) 600mm ext. 300-3900mm 128MCZ 64380 150-7350mm 50mm 0.01mm With (1) 100-150mm head, (1) ea. 50, 100, 150, 200, 250, 300mm rods, (1) 300mm ext., (11) 600mm ext. 300–7500mm 128CZ 128 128 with rod 78 M icrometers