Analysis of the Vintage Gillette Slim Adjustable Razor Head

The Gillette Slim Adjustable was my first DE razor -- inherited from my father. This one was manufactured in 1963.

The Gillette Slim Adjustable razor is the model that Sean Connery as James Bond shaved with in the movie, Goldfinger.

The Gillette Adjustables including the Fat Boy and the Slim are much revered in the DE-shaving community. I myself have written respectfully about my own Slim at times.

Yet the truth is that I don't like this razor very much. I prefer my Merkur 33C and 15C razors any day. [UPDATE 24Mar2015: I'd ammend that now to say I prefer my Merkur 33 and my Rimei RM2003, though I no longer have such a distaste for the Slim -- but I don't like it enough to use it in place of my two current favorites just mentioned.]

Reasons why some persons like the Gillette Slim:

• It's a twist-to-open, butterfly-door design, which some prefer to the earlier three-piece designs
• The blade-bar gap is adjustable allowing capacity adjustments from modest to large
• It is made of brass, which is durable and hefty, and is of high-quality construction
• They, the users, have fairly smooth, tough skin

Here is the reason that I don't use the Gillette Slim Adjustable razor:

• I have found the shaves it provides are a bit too harsh as compared to my Merkur three-piece razors, the 33C and 15C.

The more interesting question, in my opinion, is why are the Gillette-Slim shaves relatively harsh despite its adjustability? Let's begin with a few side views of the Slim's shave head with blade mounted:

This shows the blade reveal, exposure, angle, and gap on the lowest setting, one.

This shows the blade reveal, exposure, angle, and gap on the highest setting, nine.

The blade reveal is the distance that the edge of the blade extends from the top cap of the razor. The Slim has a relatively small blade reveal. When all other things are equal, a small reveal probably contributes to a less-harsh shave, when compared to a razor with a greater blade reveal. Unfortunately, this is neither the only harshness factor, nor the most important.

The blade gap (between the blade edge and the safety bar) is the adjustable feature in this razor. The gap is one of the major design factors that determines the shaving capacity of a razor. If one has a lot of hair to mow down, or it is thick and wiry, a larger gap will allow the blade to take a bigger, more effective bite. However, the larger the gap, the greater the risk that the blade will bite skin as well -- particularly if one's skin is rather uneven or loose. So what many believe is that if they have sensitive or otherwise at-risk skin that may be loose or uneven, the shave harshness can be dialed down by reducing the blade-bar gap via the adjustment feature of the razor. Unfortunately, that isn't exactly true as we shall discuss below.

The capacity of the razor can be adjusted, and this will also adjust the riskiness of the shave, but doesn't affect two key factors that influence harshness of shave on sensitive skin. Those two factors are blade exposure and blade angle.

Blade exposure is the degree to which the blade edge lies above or below the shaving plane. The shaving plane is determined by the edge of the top cap and the safety bar. So when viewed on its edge, the shaving plane in these pictures would look like a straight line that goes from lower left to upper right as shown below.

With the razor set on nine and the shaving plane drawn in, one can see that the blade exposure is positive; that is, it lies protruding unprotected above the shave plan rather than on the shave plane or within the protective cove of  the top cap and safety bar.

Even with the razor adjusted to one, the blade edge is just slightly above the drawn-in shaving plane, though this slightly-positive exposure is more easily seen when this photo is more greatly enlarged. (Click on the photo to see an enlarged version.) Note also the acute angle of the blade in relation to the shave plane. Then compare this to the angle of the Merkur 33C, below.

So contributing to the riskiness of this razor's shave is the slightly-positive to clearly-positive blade exposure -- depending, of course, on the adjustment setting one chooses.

The final factor, which in my opinion contributes most to the relative harshness of the Slim's shave, is the blade angle in relation to the shaving plane. The smaller the acute angle (less than 90 degrees), the more the blade tends to slice hair and scrape less. When one compares the blade-to-shave-plane angles of the Gillette Slim to the Merkur 33C as shown below, the 33C has a significantly smaller angle, thus slicing more rather than scraping hair off the face. This slicing action is much more face friendly, much less harsh -- especially when combined with a slightly-negative blade exposure and a modest blade-bar gap.

[CORRECTION UPDATE: After printing enlarged versions of these photos, extending the shave-plane and blade-angle lines, and then measuring the blade angle with a protractor, I have proven my eyeball assessment of these angles to be incorrect. When set to one, the Gillette Slim's blade angle is about 31 degrees, and when set to nine, is about 35 degrees. Especially at the lower setting, this angle has little to do with the extra perceived harshness of the shave. If the relative harshness actually exists, it is more likely due to the positive blade exposure combined with the larger blade gap when measured along the shave plane and as compared to the Merkur.]

The blade relationship to the shave plane on my beloved Merkur 33C. Note the blade edge is slightly under the shave plane, the blade gap is smaller even than the Slim on its smallest setting. Most importantly, note the acute angle of the blade in relation to the shave plane is smaller even than the Slim set to one. [UPDATE: Smaller, yes, but not by much.]

It is true that these design characteristics limit the 33C's capacity, but large capacity isn't needed for those who shave daily. For those who need both large capacity and face friendliness, the Merkur open-comb razors may be a great option such as the Merkur 15C.

So as one can see from the photos, the much-beloved and admired Gillette Slim Adjustable razor may be a well-made instrument, but one that will offer those with sensitive skin or otherwise at-risk skin the potential for a harsh shave, when compared to other more face-friendly razors such as the Merkur 33C Classic. In fact, I go as far as to suggest that most, if not all, TTO razors have this larger blade-to-plane angle, when compared to select three-piece razors, which renders the TTO shaves relatively harsh. That has been my experience with every TTO razor I've tried -- even the otherwise mild-shaving Weishi 9306-F (a.k.a. the Micro Touch One razor).

[CORRECTION: When I'm wrong, I'm wrong. The blade angles, as noted above in the correction update, are not significantly different between TTO razors and three-piece designs -- especially when the adjustables are set to their lowest setting.]

In sum, the rather large acute angle of the blade makes TTO razors in general -- and the Gillette Slim Adjustable in particular -- unnecessarily harsh on my sensitive and at-risk skin, especially when combined with its positive blade exposure irrespective of adjustment setting. So it sits in the shoe box in my closet unloved, unused because it is clearly not the best razor for those like me who want minimal harshness in their DE razor.

Like Walter Cronkite used to say as he closed his evening news broadcasts: "That's the way it is." [Please see the correction update, above.]

Happy shaving!