The height gage (gauge) is a versatile precision measurement tool that comes in several different styles. There is the old-fashioned vernier style, the dial height gage, simple or complex electronic gages and the gage block based styles; read on…
What to look for in a height gage
These styles are also listed in order of increasing accuracy. The vernier is the least accurate (though it is actually remarkably precise), the dial is more accurate, the electronic height gauges are even more accurate, and finally the gauge block based styles are the most accurate. Though there are many opinions about which is the most accurate!
The LS Starrett company has been making their vernier gauge, style 255 and 255M Series for decades, and some toolmakers prefer this style. Mitutoyo makes a Series 514 and 506 vernier gauge that has stood the test of time and is still in use worldwide. Very often, these are used primarily for scribing lines during the layout of tools and fixtures.
Dial height gauges are more convenient to use than verniers, and are an inexpensive upgrade. They quick and easy to use, with very little chance of reading error. They often come with scribing attachments and counters. The Mitutoyo Series 192 and the Starrett 250/250M Dial Height Gauges are popular models.
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An authoritative book, The Metrology Handbook, Second Edition provides a foundation for understanding basic metrology and calibration principles and practices.
Electronic Height Gauges
Once you enter the world of electronic height gages more possibilities open up. One major advantage is the ability to use SPC data output connections. This feature enables the operator to upload measurements to a database for analysis in real-time.
Better electronic gages have an absolute linear encoder built in, which eliminates the necessity of setting the reference point at every power-on. Also no over speed error will occur with these models.
An inexpensive electronic model is the Starrett 3751 Series, which is basically a digital caliper mounted vertically in a base, with a scriber or indicator attachment.
At the higher end you find the Starrett Altissimo gage, the Trimos, Sylvac, Fowler, Mahr Federal, Brown and Sharpe, Mitutoyo and Tesa brands.
These sophisticated precision measurement tools have many special features that make them very useful and versatile.
Basic Metrology for ISO 9000 Certification
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Gauge block based height gauges
This style is the most accurate of all, with permanently wrung together precision gauge blocks. The Starrett Digi-Check and Mitutoyo Height Master are both high quality tools found in many mold making, tool-and-die, aerospace and precision machine shops.
Things to look for in an electronic height gauge
- Hardened and ground base that slides easily over the granite surface plate, with an ergonomic handle for ease of use
- Sufficient measurement range
- Smart probe that can measure I.D. and O.D. without attachments
- LCD display that is large, easy to read and easy to use
- Adjustable beeper volume
- Ability to remember last measurement even after shut-down
- Speed wheel for rapid adjustment and fine-tuning wheel for final settings
- Locking mechanism for scribing
- Instant Inch to Millimeter conversion
- Automatic shut-off to save power
- Rechargeable batteries
- SPC capabilities
The height gauge is an essential precision measurement tool, found in shops the world over. Together with a granite surface plate and various attachments, nearly every type of measurement is possible, with a high degree of accuracy.