The set screws are a critical component of the PSS system. You must always use two set screws in each hole. The top one is used to lock the bottom one into place and prevent it from accidentally backing out.


The set screws come from the factory with thread locker applied, it is the yellow stuff on the threads in the cut-a-way version.


What is a one time use? If you tighten the set screw to torque once, that is your use. For example if you are installing the PSS and adjust it, tighten the set screw then realize the adjustment was wrong you now need to use a NEW set screw. If you look closely you can see how the used screws flatten. They will not score the shaft, like when new and sharp, to lock the rotor in place with a second use.


If you are in an absolute emergency you can swap the screw that had been the top "locking" screw for the bottom one, but this is still not advised as a regular practice. PYI recommend using new set screws with each tightening and loosening of the set screws.

PYI is glad to ship them out to you for a very minimal charge. Please, for your own good, DO NOT RE-USE set screws.