unclesyd and CoryPad,
Thanks for your replies. Now to do more research.
unclesyd, I assume that you mean that if I locate torsional strength values for UTC steel and multiply it by 0.4 then I have the torsional value for unhardened stainless?
Therefore, it seems that stainless is weaker than whatever UTC steel is. I am trying to identify that now.
CoryPad, The PDFs are very good resources. It's been a while since I did mechanical analysis because I generally am doing electrical engineering. From reading I did this morning I believe that "yield" implies repeated use and failure versus single stress to failure test.
As I view torque strength, I was thinking that I need to know what the empirically derived torque limit is for a range of 303 stainless steel shaft diameters as determined by the manufacturer, because that is standard stock for sale, so I can purchase the appropriate diameter that they sell. I also assume that some sort of derating is required to ensure that failure does not occur in normal usage.
I thought that there are emipirically determined tables indicating the torque limits in this case, whichever it would be, similar to the electrical constraints presented in electrical component data sheets.