X's 3 on using a dremel like tool on a crossbeak. We keep a regular weekly trimming schedule so the quick doesn't grow and we can keep it to a manageable length. Just keep in mind, if you go with a dremel like tool that they work quickly (which is great) but 1) you don't want to pare it down too much...just before you see blood or a tiny bit of blood is ok. Have some QuickStop or corn starch handy to plug up the bleeding and 2) those tools get hot since it's fast friction. Keep your session short. We actually blow on the site to help keep their beak cool.
For us, we found the manual nail clippers put too much torque/pressure on the beak, head & neck. The dremel lets us take off small amounts (try to get a small head in case you need to do the underside of the upper beak, that way you can better avoid hitting the tongue or inside of the bottom beak) quickly and with no pressure on the head or neck....just vibration. But from having done 3 different birds, they all seem to react when you first touch it to their beak (who wouldn't?!) but quickly settle down and dare I say relax or at least tolerate it very well.