Friday, August 11, 2017

A Meditation on Early Gillette Razors with Modern Blades

It was an eye-opening experience a few months ago, when I saw a c.1918 Gillette razor and original (three-hole, round-end) blades. The blades had a very shiny finish, were thicker than modern blades, and were also less flexible -- probably owing to their thickness.

So this morning (after my vintage straight-razor shave), while thinking about an article for today, I began to meditate on how a modern, thinner blade might affect the shave character of early Gillette razors. I've heard that their shave character is rather aggressive, when using modern blades. So that begs the question, is it the modern blade thickness or the innate character of the design that determines their shave character? Put another way -- and perhaps more accurately -- does a modern blade make these razors' shave character different than the designers intended?

I've not had the experience of shaving with one of these early razors, which were designed to shave with Gillette's early, thicker blades. (Maybe I'll ask my friend to borrow his razor.) However, let's do some ratiocination together, and see how a modern, thinner blade might affect the shave character of these early razors.

My thought-experiment analysis begins by considering the effect of razor shims in a two- or three-piece razor. The shims will mimic using a thicker blade, but the effect may simply be easier to envision.

A shim between the blade and the baseplate widens the blade-bar span (and gap, obviously) in a modern safety bar razor. This also changes the geometry of the blade angle and exposure* in relation to the shave plane formed by the top cap and baseplate. [*Note: I define blade exposure as the degree to which the blade edge is above or below the shave plane. I define blade reveal, which is not discussed in this analysis, as the amount of blade that is visible beyond the top cap.] This shim-induced geometry change increases both blade exposure and blade angle, which thereby increases razor aggressiveness of shave character.

A shim between the blade and baseplate in an open-comb razor, has the same effect. (Despite common mythology that open-comb razors are aggressive in shave character, the primary difference between open-comb and safety-guard razors of identical geometry is that the open-comb designs have an improved ability to shave hair of any length without clogging.)

A shim between the blade and top cap has a different effect. The increased distance between blade and top cap reduces the blade exposure, much like a taller person behind the wheel of a car can see a bit more pavement just beyond the front bumper. But, surprisingly, by elevating the top cap in relation to the blade increases the blade angle in relation to the shave plane.

So let's summarize what we've figured out so far regarding the effect of using shims to simulate a thicker blade in a three-piece razor:
  • More aggressive orientation of the baseplate in relation to the blade edge in both blade angle and blade exposure
  • More aggressive orientation of the top cap in relation to blade angle
  • Less aggressive orientation of the top cap in relation to blade exposure
These conditions suggest that a thicker blade will, in sum, likely make the razor shave with a more aggressive shave character owing to the increase in blade angle and somewhat of a cancellation effect in terms of blade exposure. 

Using this type of analysis, it's easy to understand, then, that a thinner blade will have the opposite effect:
  • Less aggressive orientation of baseplate -- less aggressive (smaller) blade angle and reduced blade exposure
  • Mixed impact due to orientation of the top cap -- less aggressive blade angle, more aggressive blade exposure
So it can be concluded that a thinner blade will tend to make two- and three-piece razors have, to some degree, a less-aggressive shave character.

One might therefore conclude that vintage Gillette razors that were designed to shave with the original round-ended, three-hole blades had a more aggressive  shave character that might be experience today using modern, thinner blades.

Hmmh. Imagine that. I would have guessed otherwise.

Happy shaving!

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