I am a mechanical engineer recently thrown into the SPC arena. I know little or nothing about the subject, but have been reading voraciously. I have started to gain a basic understanding of the topics, however, I can find no literature that connects GD&T to SPC. I am primarily interested in Cpk. My problem is that I don't know if Cpk is the correct index. Most of the parts are machined and we have developed key characteristics. The problem comes in trying to figure out the math. Any help will be greatly appreciated. Thanks.