THere is a big difference between 6000 psi and 28,000 psi. The common rail stuff is definitely NOT something most machinists could make, at least so it will last. We are talking making sub-micron (ten-thousanth to hundred-thousanth) tolerances, heat treating, using the right alloys, and doing it consistently. It is a very specialized area of manufacturing. Even Bosch has trouble making the stuff right. Look at all the trouble the Ford and Chevy guys have experienced with their OEM common rail stuff. 28,000 psi is a lot of pressure.