Originally Posted by Sparky
If I'm not mistaken, engine mount wobble (wet dog shake) is mostly rotational...
The operative word there is "mostly"...
My Hiperbipe will set up a resonance with the spring gear at certain taxi speeds/RPM and the spinner wobbles very noticeably in relation to the cowl. This is a non concentric path that in extreme cases will contact the cowl with the spinner backplate. The mounts are admittedly getting soft, but the point remains - consider some angular displacement when setting up minimum clearance from a very expensive propeller blade.