This technical information has been contributed by
Sirois Tool Company, Inc.

Precision Gages

Precision Gage

Custom Gage Fixtures can range from large-part inspection devices priced in the hundreds of thousands of dollars, to inexpensive gages designed to take quick measurements of thousands of parts. Although high-quality CMMs (Coordinate Measuring Machines), height gages, and other metrology tools are essential, custom gage fixtures that hold the parts or assemblies in place and ensure accurate measurements are necessary in many applications.

Walk onto any shop floor and you'll inevitably see custom gage fixtures holding down the fort. Like the metrology tools they support, these custom gage fixtures can be pricey or cheap, simple or complex. Designing and purchasing the right custom gage fixture is just as important as selecting the right gage type.

Some gage manufacturers supply the custom fixtures needed to hold their devices, some work with fixture suppliers and some let their customers purchase custom fixtures on their own.

Selection of the actual gage to be used with the custom fixture is critical. The gages can be mechanical or digital. Innovative state-of-the-art digital and mechanical gages offer an unequaled combination of excellent standard features, user-settable options, and custom features. Precision gages are well known for their accuracy, sensitivity, trouble-free long life, and ease of operation.

Mechanical Gages (Dial Indicators)

Here are some useful tips to help you select the Dial Indicator that will best meet your requirements:


Select an indicator that is closest to 10% of the tolerance spread. For example, if acceptable tolerance is .001", select an indicator having .0005" graduations. This will give a span of 10 divisions on the dial.


Two main selection criteria of mechanical gage size are:

Revolution Range-

Select a dial having the required graduations. The ideal range is one which allows the tolerance spread to cover one-tenth to one-fourth of the dial.

Total Range-

AGD (American Gage Design) indicators typically have a total range of 2.5 times the range per revolution, sufficient for most applications. Longer total range requirements up to 5" or 50mm can be met with a long range dial indicator.

Electronic Gages

Electronic gages are the most advanced digital indicators in the world. These highly advanced digital indicators, featuring advanced CMOS Complementary Metal Oxide Semiconductor)technology for unparalleled reliability, now add the flexibility of user-selectable, user-programmable, and user-definable parameters.

The result: gages where accuracy can be easily assured and maintained, and more important, gages that can be custom-tailored by you and your staff to meet measuring specifications unique to your application or industry.

Capabilities range from basic gaging to models with fully programmable ratios. These gages are so technologically advanced, they not only can satisfy the most demanding gaging requirements today, but also are designed to meet and exceed the expanding precision measuring requirements of tomorrow.

Precision electronic digital indicators can be used in a wide variety of applications, on all types of inspection and measuring stands, even in your hand. Large, easy-to-read LCD (Liquid Crystal Diode) displays offer a clear view of the reading, even from a distance. The best examples interface with leading software and data collection devices for use as complete SPC and SQC Statistical Process/Quality Control) systems.

This technical information has been contributed by
Sirois Tool Company, Inc.

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