George Schuetz Director of Precision Gages
How To Become A Master Of Deviation
In the June 2009 issue, I wrote about how “less” can be “more,” by purchasing lower-grade master rings and discs and using their certified size—their master deviation—to improve the gaging process accuracy. This topic sparked a number of questions and some confusion, primarily because I did not have space to talk about actually applying this technique on the shop floor.
Read MoreComparative Gages and Temperature Compensation
The use of electronic temperature compensation in gaging has become a valuable tool in improving accuracy as well as gage repeatability and reproducibility (GR&R) in harsh manufacturing environments.
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Dealing With Dirty Patches
Gage calibration is a routine process followed by most users of precision gages. How regular a gage needs to be checked and its performance documented is usually defined step by step in a documentation procedure.
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Charting Roughness For Grit-Blasted Surfaces
When an engineer includes a surface finish spec on a print, the intent is usually not just to make the part look good. Surface finish affects how a part will fit, wear, reflect light, transmit heat, distribute lubrication and accept coatings. The finish should be determined by the part’s function: A surface should fulfill engineering requirements without producing a higher-quality finish than necessary.
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Striking The Right Chord For Partial Diameters
Measuring the diameter of a hole is one of the most common inspection tasks in a production environment. Given the number and types of tolerances for diameters, many different gaging techniques are available to do these checks. From calipers to air gaging and everything in between, there is an appropriate gage for the application.
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Caliper Tips And Tricks
Calipers, which can be Vernier, dial or digital, are versatile tools for basic length measurement. They can be used on the shop floor, in the inspection room or even in the home by hobbyists.
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Skidded Probes For Roughness Measurement
ANSI and ISO standards include many different parameters for measuring surface finish. While these parameters are useful in many applications to ensure or enhance functionality, Ra, or average roughness, is by far the most common measure of surface finish. It is included in most specs, and it is both a good starting point and a basic benchmark of process consistency.
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Measuring Surface Finish On Large ODs
The irregularity of a machined surface is the result of the machining process, including the choice of tool, feed rate, speed of the tool, machine geometry and environmental conditions. This irregularity consists of high and low spots that are machined into a surface by the tool bit or a grinding wheel. These peaks and valleys can be measured and used to define the condition and, sometimes, the performance of the surface.
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Measuring Squareness With Air
The right angle is one of those things that man has created in his mind. In nature it happens only by chance. However, the importance of this concept—which results from the perpendicular intersection of lines or surfaces—applies to many things, including architecture, civil engineering, agriculture and manufacturing.
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The Point Of Error-Free Measurements
Test indicators are extremely useful and versatile test instruments. Spending a little time worrying about the details of the contact points will help improve the whole measurement process.
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Pushing Air Gaging Limits
Air gaging allows you to measure many jobs faster, more conveniently and more accurately than other gaging methods.
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The Long And Short On Depth Gages
Depth gages are among the simplest of indicator gages, typically consisting of a short-range indicating device mounted through a reference bar or plate. Though they may be simple, depth gages are used in thousands of critical applications.
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