This improves repetitive accuracy when conducting comparison measurements in the second axis, and when used with a rectangular gage block
, can provide accurate depth measurement on cones.
Even for gage block
steel, a well characterized material in dimensional metrology applications, the CTE value is typically known only within [+ or -] 1 x [10.sup.-6] / [degrees]C .
Minimizing Error Sources in Gage Block
Mechanical Comparison Measurements.
To implement this approach, use a gage block
equal to the dimension entered in the "specimen geometry" to determine the gap between the fixtures, and zero the LVDT with the gage block
defining the opening.
In the United States, they had become so important that when the gage block
supply was cut off during World War I, the government relieved the problem by having the Bureau of Standards (now NIST) develop a method to mass produce blocks for industry.
Compensation may be made for measurements taken at other temperatures." If we wanted to calculate the thermal expansion of a 4" steel piece or gage block
that was being measured in a 76[degrees]F environment we'd use the CTE for steel (0.0000115).
Representing the state-of-the-art of precision gage block
calibration is the expanded uncertainty of 10 nm to 30 nm on gage blocks
of 10 mm to 1000 mm in length (12).
The TESA UPD gage block
comparators can be used for both direct and comparative measurement of gage blocks
Edmunds Gages will demonstrate the CAG QCM computer amplifier, Accu-Setter microprocessor gaging column, Trendsetter analog column, 5 and 20 gage block
comparators, air gage tooling and cylindrical gages--rings, plugs, and setting discs.
"It is never out more than 0.000050~; the machine we almost bought would be out 0.0004~ measured by a gage block
," says Wirtz.
"Formerly we relied on gage block
setups and digital height towers for our inch-metric accuracy assessments.