We request two days on Engin-X to carry out commissioning tests on a pair of new piston-cylinder cells and their associated hydraulic press. Although intended primarily for use on HRPD, the high-capacity translational and rotational stage on Engin-X will make possible precise positioning and orientation of the equipment, and allow access from all sides for application of custom shielding. We propose to establish the pressure generation characteristics of the 20 kbar cell on day one by compressing NaCl, which has a well-known equation of state. On day two we will assess our ability to map phase transitions by investigating the I - II and II - III sequence of transformations in calcite at, respectively, 14.6 and 17.1 kbar.