Hi Andrew , It is possible that you could have the wrong spinner adaptor and the eng of your crankshaft is screwed all the way in and is bottoming out againt's the spinner adaptor nut. I have had that happen before. The other possiblity is you have the allen screw too far in , you need to remove the allen screw at this point to find out if the crankshaft is bottoming out again't the back side of the spinner adaptor nut. If it will tighten up then, you might have to shorten the allen screw if it too long. Hope that helps you.