The problem with drilling and reaming is there is no guarantee that the reamed hole is concentric as drills cut an oval hole and the reamer may end up off centre.

For small holes like this the best way to check is with the shank of a drill set... a 7.9mm drill (checked with a micrometer) will do as a test... although the stepper shaft is the ultimate test! A bore gauge will also do (6th one down)