Why was Rabbi Moshe Feinstein skeptical about allowing lift and cut shavers?

Question

From Koshershaver.org

It is important to mention that Rav Moshe Feinstein was very skeptical about permitting the use of a lift and cut shaver when it was first shown to him in his later years. One should bear in mind that the widespread heter to use electric shavers is primarily because Rav Moshe, being the posek hador of the past generation, permitted their use. Most poskim in Eretz Yisroel on the other hand, forbade their use. Consequently, it is questionable how a person who relies on Rav Moshe’s shitah with regard to shaving, can go ahead and use a lift and cut shaver which Rav Moshe himself was skeptical about.31

Footnote 31: This is what I heard from Rav Belsky, Rav Dovid Feinstein and Rav Reuven Feinstein. See Halichot Shelomo page 11 who gives another rationale to permit shaving...

Why was Rav Moshe Feinstein skeptical about lift and cut shavers? What makes their halachic status different from other electric shavers, which he permitted based on the idea that they act like scissors rather than like a razor? Doesn't the lift and cut shaver do the same thing?

Answer 1

In theory, the "lift-and-cut" is lifting the hair from under the skin's surface and therefore cutting below the surface of the skin. This is what a razor does (based on the motion of how it drags the skin), whereas a scissor never goes below the surface.

I must observe that Rabbi Moshe Feinstein's grandson-in-law and student, Rabbi Shabtai Rappoport shlit'a, has looked at the patent applications for these "lift-and-cut" shavers, which he considers more truthful than their marketing materials. The patents don't sound like it's really cutting as close as a razor.

Answer 2

there are two aspects to the prohibition of shaving which are cutting and destroying. in theory one could only do one of those and not be breaking the halachah. for this reason scissors or hair removal creams/powders have been used without problem. the electric razor has been compared to the cutting of scissors. the introduction of the lift technology might be introducing an aspect of destroying comparable to using tweezers. thus a shaver with a lift mechanism may be both destroying and cutting the hair at the same time. If one is concerned the lift device is removable from most shavers who have this. the other view is that since the shaver has a screen which separates the blade from the face there is no concern of both destroying and cutting and the electric shaver is just like scissors. There are many views on the discussion of shaving and it is best to talk to your rav about what decision you should follow