In this video I fix all your problem. You have a lot of naked edges, to find them I used script that is in the end of this post.
You chose very bad approach to make your object, I think first you had to make perfect cylinder or whatever you wanted and then trim it and modify. Intsed of this as I can see you made it from diffrent pieces.






script: /* Show naked edges */ var gd = moi.geometryDatabase; gd.deselectAll(); var breps = gd.getObjects().getBreps(); for ( var i = 0; i < breps.length; ++i ) breps.item(i).getNakedEdges().setProperty( 'selected', true );