[HN Gopher] Why is a Guillotine blade diagonal?
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       Why is a Guillotine blade diagonal?
        
       Author : jandeboevrie
       Score  : 39 points
       Date   : 2024-08-25 19:21 UTC (3 hours ago)
        
 (HTM) web link (pepijndevos.nl)
 (TXT) w3m dump (pepijndevos.nl)
        
       | eternityforest wrote:
       | Does being pushed sideways matter? If the knowArt test was on a
       | small scale it might not have had the inertia of the full size.
        
       | userbinator wrote:
       | I thought this would be about paper guillotines.
        
         | dylan604 wrote:
         | what paper guillotine has a diagonal blade? all of the ones
         | I've ever used were curved
        
           | ce4 wrote:
           | But thats because the cutting angle changes when depressing
           | the lever. The curvature is meant to counter that to some
           | extent.
        
           | njb311 wrote:
           | A printer's guillotine that cuts hundreds of sheets at once
           | has a diagonal blade.
        
           | userbinator wrote:
           | The point is that they cut at an angle.
        
         | khazhoux wrote:
         | What should we take away from this comment?
        
       | rolph wrote:
       | this creates shear, lengthens the amount of blade edge, and
       | directs force to a smaller contact surface than a perpedicular
       | edge.
       | 
       | [But the story goes that the real reason the blade is diagonal is
       | that the king suggested it might help with people with fat necks]
       | 
       | thus proclaimation was the lead contributor.
        
       | beefnugs wrote:
       | Cause someone thought the sound of SHIIINK was some terrifying
       | original sound as opposed to clever chopping carrot
        
         | hinkley wrote:
         | Guillotine proposed his device as a more humane alternative to
         | traditional modes of execution like being drawn and quartered.
         | 
         | And contrary to legend he did not die by his own device.
        
           | woleium wrote:
           | Her device?
        
       | themaninthedark wrote:
       | Without reading the article, my guess would be because it allows
       | the force to be focused on a smaller area at the start of the
       | cut.
        
         | blackeyeblitzar wrote:
         | Wouldn't everything that is a blade be designed this way then?
        
           | salomonk_mur wrote:
           | Almost everything that is a blade is designed to be curved or
           | slanted, yes.
        
           | evilduck wrote:
           | Many are. Scissors, drill bits, even the way most people use
           | a kitchen knife, they put as much force onto as small of area
           | as possible. At certain differences in scale it won't matter
           | (razor blade vs a single hair), but how a cut is performed is
           | definitely part of the design process.
        
           | tengbretson wrote:
           | Like a mandolin slicer?
        
           | Spooky23 wrote:
           | They are. Except for Japanese style knives, all knives have a
           | slant.
           | 
           | The Japanese knives are only sharpened with a single edge,
           | however. So they in a profile view look like a tiny
           | guillotine.
        
           | tomjakubowski wrote:
           | chopping vegetables with a chef's knife applies the same
           | principle
        
         | nosianu wrote:
         | > it allows the force to be focused on a smaller area at the
         | start of the cut
         | 
         | Is this really true when the object to be cut, a neck, is
         | approximately spherical?
         | 
         | I can see the truth of the statement for a straight horizontal
         | rectangular object, but for a cylinder-like shape?
        
           | loloquwowndueo wrote:
           | Cylindrical not spherical.
        
       | im3w1l wrote:
       | Less likely to bounce off a bone would be my guess? A diagonal
       | blade will push obstacles out of the way.
        
       | samstave wrote:
       | Same Reason a Katana is curved, while the temp causes this, it
       | augments the blades cutting angle, length, draw.
        
       | d--b wrote:
       | Which begs the question: why wasn't it shaped like a ^
        
         | montroser wrote:
         | It'd be tough to keep that inside corner sharp...
        
           | mc32 wrote:
           | Two overlapping triangles would work. A little work in
           | disassembly reassembly, but not much.
        
             | the_gipsy wrote:
             | Just make it a V.
        
         | almostgotcaught wrote:
         | "to beg the question" means "to dodge the question". You mean
         | "prompts the question".
        
           | bee_rider wrote:
           | Dictionaries now seem to give both the definitions. Such is
           | the fate of us victims of the dynamic English language.
        
         | ReptileMan wrote:
         | Unlike cigar cutter on which you apply a constant force, a ^
         | guillotine has fixed potential energy. It will get to the
         | toughest part of the neck when bigger portion of it is spent,
         | so it may or may not be enough to cut trough.
        
       | lupusreal wrote:
       | I'm sure diagonal blades are more practical, but style must be
       | part of it right? It was a theatrical method of execution after
       | all, done for crowds.
        
       | yumraj wrote:
       | _Slant_ razors, like the Merkur slant, are also slightly angled
       | for an easier shave.
       | 
       | I have one and can vouch for it.
        
         | tithe wrote:
         | One colloquial term for the guillotine was (is?) "le rasoir
         | national" = "the national razor."
         | 
         | Other colorful terms include "the regretful climb", "the
         | silence mill", "Capet's necktie", "the patriotic shortener",
         | "half-moon", "timbers of justice", and "Charlot's rocking-
         | chair".
         | 
         | https://en.wikipedia.org/wiki/Guillotine#Names_for_the_guill...
        
         | zikduruqe wrote:
         | Run that with a Feather blade, and buddy, you will be
         | facesturbating all day.
        
       | valeg wrote:
       | Reminded me of this "La Revolution francaise" scene
       | https://youtu.be/YPiiAHSi_48?t=5236
        
       | readthenotes1 wrote:
       | Unreadable in dark mode :(
        
         | skribanto wrote:
         | Looks fine to me
        
         | VonGallifrey wrote:
         | It is white text on black background by default. Do you have
         | some browser plugins that mess with the website content?
        
       | nabla9 wrote:
       | One explanation is missing: the angle of the edge.
       | 
       | If the blade edge has been sharpened to 20 degree angle, it has
       | the same 20 degree cutting angle when used diagonally. The
       | effective cutting angle decreases in the direction of the cut
       | when you rotate it. The smaller the angle, the sharper the knife.
        
       | cft wrote:
       | Mainly because the slicing motion separates fibers in the fresh,
       | it's more effective than blunt force. Same with a knife.
       | 
       | It's interesting, however, that this post is much higher on the
       | front page than the post about Durov's arrest by the French ever
       | was, despite having 1/10th the number of comments during a
       | similar time period.
        
       | Giorgi wrote:
       | Quite the fascinating story, I dig up a bit more:
       | https://archive.org/details/memoirsofsansons00sansuoft/page/...
        
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       (page generated 2024-08-25 23:01 UTC)