or is the screw too long to tighten the spinner? if the prop blades are too big for the slots enlarge the slots if the screw is too long cut it i've had to do both. i hate wooden props they seem to loosen up due to expansion caused by humidity. i'll open the slots for an apc prop. by the way did you know that spinners come in slot sizes? there's a 3inch with small medium and large props