Man, you dont know how long it took me to figure that button out! Of course a better vocabulary couldnt have been used. Once I understood what it did, the proverbial light went off in my head. What an idiot I was. As I learn more about Mach, machining, CNC and electronics inevitably all of those meaningless words on various Mach settings and configurations start to make sense (key phrase was, start to). These people (real machinists and cnc software gurus) are in deep. I have to read some chapters (all very well sequentially organized and written) many times I have to read a chapter 10 times to get 10% of it. No wonder my teachers (I am 50 now) were frustrated, denial is not a river in Egypt. Glad we both learned something today. Now if I could figure out tool offsets on my lathes turret.