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How AGMA Brings Standardization To The Manufacture of Bevel Gears

June 21, 2018

When talking about the ‘quality’ of bevel gears, what quality are gear manufacturers referring to? What is the measure of quality for bevel gears, indeed, all gears? And how does the industry ensure standardization between gears cut by different manufacturers.


Here, in North America, nearly 500 gear cutters and millers have joined to form what is called the American Gear Manufacturers Association (AGMA). AGMA has developed standards for measuring gears, checking variation in tooth alignment and more, and encapsulated them in the eponymous unit ‘AGMA’.


The AGMA standard has taken much guesswork out of the quality of bevel gears; however, it simply cannot provide a complete measure of gear quality.


The quality of bevel gears is expressed in a number followed by AGMA: for instance, 12 AGMA, which denotes, amongst other things, the tooth geometry; essentially, the higher the number, the smaller the tolerance.


With the prevalence of AGMA, it has even been accredited by the American National Standards Institute to define virtually all aspects of gear manufacturing and quality control in the United States.


AGMA standards delve deeper into gear manufacturing than just the accuracy of the cutting. AGMA ratings for bevel gears, for instance, encompass also the material quality and the heat treatment they must undergo.


AGMA rating has become the common point of comparison between gear manufacturers from across North America. In fact, such has been the reach of the standard that, despite being applicable to gears manufactured not as part of complete assemblies, even manufacturers of equipment with enclosed gearing have taken to the AGMA standard.


In assessing bevel gears, paying attention to AGMA ratings is a great way to judge a number of qualitative factors of manufactured gears. Tooth shape, placement, tolerances, profile variation and more are encapsulated in the AGMA number. However, there are a number of factors that determine the quality of bevel gears that are not considered in AGMA Some examples of this are the purity of the raw material, its content of sulphur, the depth of heat treatment, mechanical or chemical corrosion.


As such, simply relying on AGMA is not a complete measure of gear quality. Bevel gears must be manufactured by reputed gear manufacturers to ensure you get that specification of gear which you expected.


True Gear manufactures a complete selection of splined shafts, external and internal gears, and internal splines. All gears and spline shafts undergo a thorough quality inspection process and our gears and splines can be customized to meet your volume and size requirements.