Quote Originally Posted by sangerdan View Post
The shaft is centerless ground, to be out of balance either the material would have to be not homogeneous or the taper machined out of concentricity to the body of the shaft. The keyways should be 180 to each other so they would offset each other. Not straight is not out of balance so if your shaft is somehow found to be out of balance I would throw it away as there is a serious issue. Your coupler is probably more of a balance issue if you have the garden variety coupler. I was surprised when I suggested splines on the shaft and prop on the other thread that I wasn't tarred and feathered, but I too would like to if anyone has pursued it.
You may see someone tinkering with it soon on a heavy boat that is rough/tough enuff to bust up a shaft/strut/coupler... Thats all Im gonna say about that...