Later On

A blog written for those whose interests more or less match mine.

Perfect shave and thoughts on why a slant works

with 9 comments

SOTD 7 Sept 2015

Today is the 11th shave from the small sample of grated Meißner Tremonia’s Pots o’ Milk, which I mashd into the bottom of the bowl shown, and I think perhaps it has three shaves remaining.

The brush is Simpson’s Wee Scot, a marvelous little brush with ample capacity for a full shave. With a well-lathered beard, I set to work with the Merkur 37G slant and easily reached a BBS result.

For some reason, a few are reluctant to accept the efficacy of the slant design, despite a mountain of testimony from those whose experience with the slant is that it shaves more easily, encountering less cutting resistance, and more easily achieves a BBS result. Some don’t accept this because it doesn’t match their own experience—for example, one man said that, while the slant does cut more easily, he himself cannot get a BBS result, and so he believes that no one else can. This contradicts something that we know about shaving: the YMMV aspect, that something that works for one may not work for another. (It also contradicts the experience of those who, like myself, find that a slant more easily produces a BBS result than a regular razor.)

Others disbelieve the slant’s efficacy on the basis of theoretical objections. For example, if the slant’s angle is 4º, some would say that is no more an angle than one would unconsciously assume with a regular razor. But of course, if one unconsciously adopts a 4º angle (something I doubt: I’ve tried it and I don’t think it can happen without conscious effort), then the slant is at 8º, not 4º. So even if one unconsciously tilts the razor a bit, the slant is still favored because its blade is tilted more.

Another objection is that the efficacy of a cutting blade does not kick in unless the angle is greater. Apparently the thinking here is that tilting a blade will not affect cutting ease until some angle is reached—10º, for example—and then, abruptly, the cut becomes easier. But this is not the way things work. As Leibniz observes, nature works by degrees, and any slant will make some small improvement over a straight-on chop, with the improvement increasing as the slant increases. So it means, even theoretically, that a 4º slant will encounter less cutting resistance than a 0º slant. It doesn’t make sense that there be no improvement in slanting until some particular angle is reached, and then at that point improvement instantly emerges.

But don’t take my word for it. At some point get a slant and try it yourself. With any new razor it will be necessary to do some renewed blade exploration: a brand that’s best in one razor may not be best (or even good) in another.

A splash of Bulgari and packing day arrives: tomorrow is the big trip to Victoria for The Niece’s wedding.

Written by LeisureGuy

7 September 2015 at 8:28 am

Posted in Shaving

9 Responses

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  1. I am suspicious that those naysayers don’t own a slant bar razor. I can shave with my 37C every day without any problems. Not only BBS but glassy smooth.

    I didn’t know I needed a slant until I tried one.

    Larry

    7 September 2015 at 8:54 am

  2. Regard the Merkur Slant, I can’t seem to get a satisfactory shave from anything else? There are no truer works spoken regarding de shaving than to each his own. My sons seem to have no problem with anything I pass on because I didn’t like it? I have the Colonel and that is a brush I really like, it seems like I use it more and more.

    Mike

    7 September 2015 at 12:02 pm

  3. LeisureGuy said:
    > “Another objection is that the efficacy of a cutting blade does not kick in unless the angle is greater. Apparently the thinking here is that tilting a blade will not affect cutting ease until some angle is reached—10º, for example—and then, abruptly, the cut becomes easier.”

    My clarification (posted here as per your reddit mail invitation for me to read this blog article):

    The 10 degree threshold you mention wasn’t a made up arbitrary number, it came from a potentially, partially-applicable (although certainly not 100% applicable) journal article, “Slicing Cuts on Food Materials Using Robotic-Controlled Razor Blade”

    From the articles research conclusions:

    “During the cut with slicing angle smaller than 10°, or pressing-only or mainly pressing cuts, blade cutting is a type II fracture due to the shear stress 𝜏𝑦𝑧. With slicing angle bigger than 10°, or called pressing-and-slicing cuts, blade cutting is a type III fracture due to the shear stress 𝜏𝑥𝑦 and 𝜏𝑥𝑧. Type III fracture uses considerable less force than type II fracture. This answered why pressing-and-slicing cuts use less force than pressing-only cuts.”

    source:
    http://www.hindawi.com/journals/mse/2011/469262/

    You can also see in this graph from the journal article’s Figure 11, that 0-to-10 and 80-to-90 degree ranges are measured as having only very very slight affects on total cutting force:

    http://www.hindawi.com/journals/mse/2011/469262/fig11/

    That said, I’m just a hobbyist researcher, and I don’t really have the expertise to conclusively interpret this journal article, nor do I know for sure if it can be prudently applied to shaving.

    It seems likely that cutting 20mm-thick raw potato bricks differs in at least some ways from cutting beard stubble, and there might be some reason why cutting beard hairs could reach the article’s mentioned “Type III fracture [which] uses considerable less force” at a less-slanted cutting angle. I can’t personally think of why beard stubble would be more affected by a 4 degree slant, but a reason might exist….

    As for personal comparison experience, I have a Merkur slant, but I do not have an otherwise identical non-slant to compare it to in regards to ease of cutting. Does such a pair of otherwise-identical slant and non-slant razors exist? So far, I personally suspect the Merkur slant’s added ease of cutting and greater efficiency in cutting is possibly simply due to greater-than-average blade exposure.

    Thoughts?

    Thanks,
    Shawn

    Shawnse

    7 September 2015 at 12:29 pm

  4. Interesting that, at least with potatoes, there seems to be a “tipping-point” sort of shift. I suppose it’s possible, but generally, it seems, improvement is by degrees, that in this context would be improvement in ease of cutting becoming greater as the slant increases. It would really be interesting to have a series of slants, with the blade slant increasing (say, in 2º increments) from 0º (a regular razor) to 12º.

    EDIT: It just occurs to me that being able to adjust the slant (as an adjustable razor) would be a dynamite idea. The Walbusch B5 is an adjustable slant, but it doesn’t change the slant of the blade, just the blade gap (like a regular adjustable). A slant adjustable that would adjust the slant would be really cool. /edit

    Of course, we do have slants between those degrees, and many—many—find that the cutting is easier and BBS is more easily achieved when using a slant compared to a regular razor. In fact, two of them commented on this post. So we have numerous observations from their experience.

    The 34C is pretty close in form to the 37C. I think it could serve as the regular razor equivalent. Indeed, I have both a 34G and 37G. The slant cuts easier.

    But I suspect this kind of evidence, along the various posts from men saying how much better the slant works for them, will not move you.

    LeisureGuy

    7 September 2015 at 1:02 pm

  5. > “The 34C is pretty close in form to the 37C. I think it could serve as the regular razor equivalent. Indeed, I have both a 34G and 37G. The slant cuts easier.”

    If the Merkur 33 and Merkur 34C have the same head design, then this blog post and photo analysis seems to make a pretty convincing argument that they differ significantly from the Merkur slant’s head design (besides just the slant):

    http://shavelikegrandad.blogspot.com/2014/11/razor-analysis-merkur-37-slant-bar-in.html

    Shawnse

    7 September 2015 at 1:25 pm

  6. I read that post some time ago and responded to it with a fairly detailed comment, which he did not approve, apparently. I’m not impressed by the post: he talks about the slant as a person who has apparently had little experience with one. For example, he harps upon the likelihood of the 37C being “harsh” and causing a lot of nicks. Had he checked with those using the razor, he might have learned that the 37C (used with a good brand of blade for the user and with light pressure) is in fact quite mild and unlikely to nick. He recommends it for those who have a tough beard and tough skin, when in fact the razor is much admired by those with tough beards and sensitive. I think his idea is that his measurements and theory are more significant than actual experience, so he pretty much ignores reports based on experience and in so doing leads himself astray. It reminds me of the (perhaps apocryphal) anecdote about those scientist who found that, based on theory, the bumblebee should not be able to fly.

    I can see why you like the article—lots of measurements—but if you step back and compare his conclusions to reported experience, you can see he took a wrong turn somewhere.

    And I’m negatively impressed by the fact that he will not approve comments that are critical of his thesis.

    LeisureGuy

    7 September 2015 at 1:44 pm

  7. I disagree with the Shave Like Grandad author on many things (including in that specific blog post) … but the article’s photos do seem to to back up my cited point that the Merkur slants seem to have a different blade exposure, blade angle, and blade gap from Merkur’s other solid bar models.

    Shawnse

    7 September 2015 at 6:09 pm

  8. Could well be. In that case the 34C and 37C are not comparable.

    LeisureGuy

    7 September 2015 at 6:23 pm

  9. I do not own a 34c but I have the 33C and 37C and they shave as differently as night and day. The slant is better by a country mile

    Larry

    8 September 2015 at 8:54 am


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