According to this article by Tzomet, it is forbidden for Jewish males to shave their beards with a razor; however, most electric shavers (with the possible exception of "lift and cut" shavers) are allowed to be used.
What about a nail clipper? Would that be more like a razor, or more like a pair of scissors/electric razor?
This came up in an answer over at Lifehacks, about alternative shavers for when an electric shaver breaks or otherwise ceases to function.
I asked this question to Rabbi Belsky one time and he said It's fine. He said clipping with a nail clipper is like cutting with a scissor, not like shaving with a razor.
I then mentioned that my concern stemmed from the Ramma who brings a gezeira from the Trumas Hadeshen that when using a scissor, the blade resting on one's face cannot be moved to do the sniping action, only the upper blade that is not touching the skin. I asked how the Trumas Hadeshen's gezeira would would work being that both cutting surfaces are moving. At this point he said that clippers are even better than scissors because they are not so much cutting with sharpness but rather like chopping with blunt force. Therefore the gizeira from the Trumas Hadeshen would not apply. That was the end of our conversation.
I especially enjoyed his last point being that reb Moshe Feinstein used this logic to say that shavers are better than scissors. Reb Moshe called it 'maaseh ktisha', an act of grinding.
Since sources permit shaving with scissors, and nail clippers basically are scissors, it should be permitted. The distinguishing factor between scissors and a razor is that scissors work by two blades in tandem, as opposed to a straight razor, or even a safety razor that cuts as a single blade.
Knowing the asker, when I was learning to shecht, I was told my knife was sharp enough if when I ran it along my arm, hair was removed. It is that sort of function which would be prohibited on the face, and I doubt a nail clipper could do that.
