It's recommended that when filing a prop, file only on back-side. Of course to remove burrs on front is fine but not full front edge. Doing so can and will through pressure balance-out leading to vibration and unwanted cavitation. I razored a prop once as I got fed-up with weeds in a weedy lake. Worked great and no more weed build-up. But I used a fine file and only on the rear of the prop, from inside (hub) to edge or start of turn. Stay flat as possible - no bevel.
__________________
|