ORIGINAL: Truckracer
ORIGINAL: ghoffman
OK, what I will try is to set the mill up with a 1/2 inch carbide end mill turned 45 degrees and cut a rectangular pattern in the spinner plate that will engage the Syssa thrust washer. This way it will have a controlled depth (say 1mm ???) and pitch to match the thrust washer and stay balanced.
That is just over the top to have to modify a spinner in this manner just to make it work with an engine such as this. If the dang Syssa engine had a large enough, properly designed prop driver hub to begin with this problem wouldn't exist. By design, there is very little surface contact area between the drive hub and the spinner backplate due to the deep grooving in the drive hub and its very small diameter. Properly designed single bolt hubs work well on most engine designs with or without spinner backplates. The Syssa would work OK too if it were larger and had a different (smoother with more surface area)machined face.