George Schuetz Director of Precision Gages
Going To The Extremes
When most of us think about measurement environments, what generally comes to mind are pleasant laboratories with temperatures controlled to 68°F/20°C—plus or minus a degree or two. Or in the worst case, we picture a gaging shop with swings of temperature between 65° and 90° F.
Read MoreCalipers: Ideal For Measurement On The Go
Although it has been around for a long time, the caliper is still an extremely versatile and useful tool for making a range of distance measurements (both ODs and IDs). While micrometers are more accurate, they have a limited measurement range (typically several inches).
Read MoreMachine Compensation
Ever since electronics first made their way onto machine tools, machine builders and users have tried to achieve some level of "automatic" process control. Certain causes of dimensional variation in machined parts—tool wear, for instance—occur gradually.
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Perfect Gaging In An Imperfect World
It is certainly not news that, more and more, gages are being forced out onto the shop floor. Tight-tolerance measurements that were once performed in a semi-clean room by a trained inspection technician are now being done right next to the machine, often by the machinist.
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Operating Characteristics And Calibration Curves
Gage accuracy is described by a number of concepts, including repeatability, linearity, calibration, and "accuracy" itself. The Operating Characteristics (OC) curve presents an easy way to visualize what these terms mean, and how they are interrelated.
Read MoreChecking For Centralization And Balance Errors
Air gaging is often referred to as a non-contact form of measurement. This is accurate, to the extent that there's no metal-to-metal contact between a sensitive gage component and the workpiece.
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Gaging Countersunk And Chamfered Holes
While countersunk and chamfered holes are similar in appearance, functionally they are quite different. Consequently, different gages exist to serve these different functional requirements.
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Never Forget The Basics
We spend a lot of time in this column discussing sophisticated gages and out-of-the-ordinary applications—so much so, that perhaps we've lately been neglecting the basics. After all, the fanciest electronics, computers and software won't deliver accurate results if good gaging practice is absent.
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Electronic Height Gages
We've looked at "basic" comparative height gages, which are used for layout tasks and other surface plate measurements. Related to these are instruments known as electronic height gages.
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Inspecting Tapers, Part 2: Toolholder Gaging
A few months ago, we discussed the calibration of conical taper masters, which are used to master taper gages. Now let's look at the parts those gages are used to inspect—toolholders.
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Assessing Gage Stability
Gage stability implies different things in different contexts. If taken literally, it may refer to whether there is something loose on the gage, or some other gage problem occurs randomly, to cause two identical trials to produce different results.
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Gaging 'Relational' Dimesions
Specifications often require inspection of dimensional relationships between two features, or between two dimensions on the same feature. Compared to single-dimension specifications (such as diameter), these "relational" specifications can be challenging to inspect.
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