George Schuetz Director of Precision Gages
Inspection Tapers Part 1: Certifying The Master
Conical parts, such as machine tool tapers, gas petcocks, and the shanks of modular prosthetic joints, must often be inspected for taper accuracy. This is usually performed with a special air or electronic gage, custom-made for the specific part.
Read MoreGaging By Computer
Computers are rarely necessities for standard dimensional measurements, although almost any application can be enhanced through the use of PC-based gaging software. And while the use of "gaging computers" cannot serve as a substitute for sound gaging practice, the potential benefits they offer are greater, and the barriers to entry lower than ever.
Read MoreMeasuring Roughness With Buttons And Donuts
The Ra parameter is the most commonly used measurement for surface roughness. Until recently, in fact, it was the only parameter recognized by ANSI, although new ANSI and ISO standards include many different parameters from which to choose.
Read MoreA Shallow Bore (This Is Not An Autobiography)
Imagine a large rotor with an ID of 12 inches. One normally uses an adjustable bore gage, or perhaps an inside rod micrometer, to check the diameter.
Read MoreTake A Stand
Bench comparators consist of an indicating device, plus a height stand that incorporates a locating surface for the part. On some stands—especially those used to measure large parts—the base itself serves as the reference surface.
Read MoreTemperature Compensation
Temperature variation is one of the most significant sources of gaging error. As manufacturing tolerances get tighter and the margin for gaging error gets smaller, it becomes an issue that must be addressed.
Read MoreCentral Intelligence
Many factors influence the accuracy of hole diameter measurements. We've seen in past columns the importance of operator skill in the use of rocking-type adjustable bore gages, and discussed how variations in part geometry may make even technically accurate measurements inaccurate from a part-function perspective.
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How to Correct for Cosine Error
A small shopfloor network lays the groundwork for large-scale, low-cost DNC throughout a major manufacturing facility.
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Electronic Gaging Basics
Mechanical gages are familiar and economical. Air gages offer non-contact measurement and ease of use.
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When Indicators Go Both Ways
Measuring and gaging are two fairly distinct forms of dimensional inspection. Measuring is a direct-reading process, in which the instrument incorporates a continuous scale of units, against which the part is compared directly.
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Look Into My Stylii: Care Of Surface Finish Contacts
Proper care of contact points is one of the basic considerations in gaging. Whether you're using a simple indicator gage or a sophisticated surface finish instrument, much depends on the condition of the sensitive contact point, which is the interface between the gage and the workpiece.
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Gaging Distance Between Hole Centers
Many of the gaging applications we've considered over the years involve size inspection of a single feature, that is, the diameter of a hole, depth of a groove, height of a gage block, and so on. Many parts, however, contain multiple features that establish dimensional relationships between two or more other parts.
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