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DE razor geometry. A system for measuring aggressive razors.

I have been trying to wrap my head around DE razor geometry regarding aggressive and mild razors.

I realize that there is a lot of emphasis on using blade gap to rate the aggressiveness or mildness of razors. Some razors even state their blade gap in the razors name. The razor lives in a three dimensional world, one dimension isn’t always going be accurate in grading the aggressiveness of the razor. If you use just blade gap measurement you can end up buying a boatload of razors in an attempt to find the razor with your desired aggressiveness. There must be a better way. Let’s use an example of automotive tires. Tires use a three-number measuring system. I have a tire with a measurement with of 215/65/15. The 215 (in millimeters) is the width the 65 is a aspect ratio it’s the percentage of the sidewall height. And 15 is the wheel size in inches. Is there a way we could use a measurement system similar to this for DE razors.

I was studying shavebythenumbers illustration. Safety Razor Parameters: Illustrated and Defined - https://www.badgerandblade.com/forum/wiki/Safety_Razor_Parameters:_Illustrated_and_Defined

There are about twelve different measurements listed with this illustration. A twelve number measuring system would be unwieldly. Is possible it could be narrowed down to three most critical measurements? Something like Blade Gap Blade, exposure/blade reveal and shave plane.

We could than say the Merkur 34C is a .71/1.41/6.53

This is just an example I really do not know what the most critical measurements are. Or are we just doomed to trial and error in finding the perfect razor.
 
One thing that changes over time and is not accounted for in the above is how your shaving technique improves over time. As my technique has improved razors I don’t like give the best shaves and become my favorites.


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Yea there is the shave angle a shaver uses I think that would be like wheel alignment. Razor angle that is out of alignment will cause skin wear. (irritation). You cant totally escape YMMV.
 
In my experience blade gap doesn't make much difference as far as aggressiveness but blade exposure does. How far the blade extends past the imaginary line from razor cap to razor guard. My favorite razor is the Timeless .68 which the manufacturer lists as having a neutral blade exposure meaning the blade edge extends to the imaginary line but not past it. Most manufacturers don't make blade exposure measurements available though. And of course, not all blades are the same exact same width so that throws it off too.
 
Judging by my own experience, aggressiveness = (blade exposure * unsupported part of protruding blade). By unsupported, I mean the part which is not thoroughly bent by the cap or not clamped by the bar and cap but is just "in the air". I can judge the aggressiveness of a razor by looking at it from the side, with the blade loaded. Maybe we should extend the existing table in the wiki with some pictures and info from the current mild razor thread?
 
Judging by my own experience, aggressiveness = (blade exposure * unsupported part of protruding blade). By unsupported, I mean the part which is not thoroughly bent by the cap or not clamped by the bar and cap but is just "in the air". I can judge the aggressiveness of a razor by looking at it from the side, with the blade loaded. Maybe we should extend the existing table in the wiki with some pictures and info from the current mild razor thread?
Ok these comments have gave me some food for thought.

I think if you can judge a razors aggressiveness by looking at it you should be able to measure it. I also understand that shaving can be very subjective but if you can implement a measurement system that is consistent anyone could use this information for their situation.

When you get to the crux of this it is how the razor holds and presents the blade to the skin being shaved. This is where the rubber meets the road or the blade meets the skin.

I did not know blades came with different widths. That could be problematic in measuring the aggressiveness of a razor.

It appears to me that blade exposure is more important that blade gap. I think than a blade exposure and a blade gap measurement are two of the three numbers that should be included.

Perhaps a measurement system is not really what is needed. Maybe a razor underwriting laboratory or a consumer razor reports would be better. A grading system if you will something like what numismatists use to grade coins. Coin grading was too subjective. No one could agree on the grade of a coin. Now they have grading companies that you can send you’re coin in and get it professionally graded. Perhaps a panel of shavers can grade a razor. A panel consisting of shavers with different types of beards. This panel could come up with an average grade or a grade per beard type. A grade for how mild or aggressive the razor coupled with the measurements for blade exposure and blade gap. If the grading is consistent than you have something to work with
 
While newer to this I am finding that numbers are not the whole story

if a Hyundai vs a Porsche have the same values in certain things I know the Porsche is going to perform better in every way based on other things build quality etc...

kinda finding this to be the same one sounds more mild but is not as comfy ? And again the driver can make something perform and depending on drivers level they might not notice the difference at this step of the game Or take advantage of the better razor :)
 
While newer to this I am finding that numbers are not the whole story

You have never watched an interview (or performed one) with a winner of the Fields medal or the Alan Turing award, have you? Although some psychologists could argue this sentiment extends to students of all math-heavy subjects and related life forms...
 
...I think than a blade exposure and a blade gap measurement are two of the three numbers that should be included...

Are you sure three variables would suffice? I can think of razor weight, polish quality, in the case of OC DEs: number of teeth, distance between teeth or at least thickness of teeth, razor coating... The two variables I mentioned previously are the major ones for me, but if you want a metric system, then it probably makes sense that all interested and experienced members chime in and we compile a definitive list.
 
A database of different razors with a rating system would be nice. You could have a spreadsheet where people contribute with their input based on different criterias. You can then calculate an avarage or a comulative normal distrution to rate the different razors and properties. If enough people contribute, this can serve as a guide for razor selection.
 
Another missing factor is which school of rigidity is being followed, full blade clamping (Wolfman etc), suspended on narrow base (Merkur)/EJ etc) , or somewhere in between. This impacts optimum stroke length and speed and ATG performance for some (clearly not all) growth patterns and types. This can be measured in terms of clamping and free end distance but factors like angle and blade bend are going to figure in.

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Blade exposure and gap measurements would be useful. Rigidity of blade clamping could be classified (subjectively) on some sort of scale.
Thanks @Slock for starting the thread.
 
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