Guys,

ABEC, which was the

*Anti-Friction Bearing Engineering Committee* when I was an apprentice and was

*reformulated* into the

*Annular Bearing Engineering Committee* some years back (I must have missed that memo), puts out the standard load requirement equations in a rather expensive set of books. I have never understood their approach of making such information (gathered by

*taxpayer funded research*) so costly as, it seems to

**me**, more people would

**use** bearings if they had that information more readily available -- but that has been the trend for the past few decades. One of the things I am looking for is a

*public domain* basis for such information I can use in my ongoing work towards writing a new mechanical design engineer's handbook (the reason I am posting stuff over at

http://www.scribd.com/Lew%20Merrick).

In any case, the limiting factor on rolling element bearing design is the

*Hertzian contact stress concentration* that occurs when a round surface impinges on another surface. The smaller the radius, the larger the

*Hertzian contact stress concentration* factor. Since a ball bearing has a sphere (one

*Hertzian contact stress concentration* factor) rolling in a radial round groove (a second

*Hertzian contact stress concentration* factor), the effect of the stress concentration is approximately doubled -- making the

*nomograph curve* of overall stress concentrations take the form of

*concentration factor* = 1/

*roller diameter*².

Back in the pre-computer days things requiring more complex calculations were reduced to

*nomographs[/] to simplify things. There were whole rafts of mathematical graph people who created them for government agencies and major corporations. If you look hard enough (older editions of Joe Shigley's **Machine Design* leap to mind), you will find *nomographs* for most mechanical design calculations.