A significant amount of metal splinters protruded from the end of the set screw hole into the hole. This was the case for both units. I needed to move forward with my renovation so I took the time to submit it. Even then it doesn't quite fit the 10mm shaft. I'll make it, but it shouldn't be that hard. I have never seen a shaft coupling with this problem. Unfortunately no picture. I was in a hurry to fix the mower.