Wie ändere ich die Maßeinheiten?

I'm a Mechanical Engineer by qualification though I worked for a long time specialising in Motion Control systems and integration with various PLC systems. I've wide experience of many types of applications from packaging machines to military and some applications that I can't mention. At home, I like to tinker and make things with wood, metal, plastics, electronics and mechanical system. I'm never happier than with a hammer and a screwdriver in my hands....