So, i’m trying to assemble two parts in ptc. A hex bearing and a hex shaft. But from I can see, there is no way to “insert” the shaft or mate the edges together in order to move it into place. When i try that it simply rotates the part. 
Pick any two adjacent pairs of planes in the hex.
if the shaft and bearing are not exactly the same size, you can put a Datum Axis down the middle of each and then use Orienting planes on each component to define it’s “clock” position.
Thank you so much! That worked perfectly!