I never said I could do it better than a machine. I tried the Dave Brown Vortec spinner first and used it for a little while. However, with my YS91, the prop nuts would hit the inside of the spinner, not allowing it to make full contact with the back plate. It was also my first attempt and the cut-outs did not go as well. The TruTurn is a little deeper/longer and uses a slightly thicker back-plate. When I tried an APC 16x4w, I ran out of threads on the shaft before the prop was tight. A thicker washer just made it hit the inside of the spinner. The Dave Brown spinner had to be cut as well. The price difference at Tower is $18.39 vs $24.49. I wished the Dave Brown had worked out better it just didn't fit right for me. I had to try combinations of prop nuts/adapters and washers to make it fit. I should have just used a 2 1/2" spinner, that way clearance would not have been an issue. I wish they had designed the nose around the 2 1/2". It makes more sense. I don't know of any prop in the .90 size range which would fit in the 2 1/4 inch spinners without modification. I haven't had any vibration problems.