J. Kissel, J. Warner In prep for today's vent, Jim and I locked HAM5 HEPI. Displacements between locked and unlocked are on the order of ~20-30 um, and 5-10 urad from nominal floating position with IPS-only, "position" loops closed. See attached screenshots, but I recap pertinent info below. dX -2.3 um dY +17.6 um dZ +23.7 um dRX +1.2 urad dRY +4.1 urad dRZ -8.7 urad I also attach pictures of the locking bolts / set screws. To lock HEPI (while attempting to preserve alignment): - Procure a CDS laptop, and open MEDM to get the DC BIAS screen of the given HEPI you want to lock - Take a screen cap of the screen before you get started. - Run all set screws and bolts into such that they're barely contacting the floating cube in each / every corner. - Using the appropriate allen wrenches (you'll need two sizes, 3/16" and 1/4"), and while watching the attached displacement screen, gently nudge the bolts further into contact until tool tight, rotating between bolts / set screws so as to not crank on any one bolt more than the others for a given tightening iteration. It's fine to do this sequentially around the corners. - Displacements from nominal on the order of a few 10s of um / urad are the precision you'll be able to lock the position. - Take another screenshot of the position and displacement once done and record. This process takes about 20-30 minutes.