#1
(This post was last modified: 01-20-2020, 05:56 AM by surfboat.)
I have a number of slants that I enjoy but have always been curious if the theory underlying their design bears out in reality. As most probably know, the general theory is that an angled blade is more efficient than a cut that is 90 degrees to an object because the blade is being applied to a smaller surface area, which reduces the require amount of cutting force (e.g. guillotine effect). I may be mistaken, but I think cutting force can be represented by the formula F= L x T x S, where

F = Force
L - length of object
T - thickness of object
S = shear strength of object


Given how thin human hair is, is there any practical benefit gained from an angled blade vs one that is straight on? In other words, there isn't much to slice through so the practical benefits are minimal?  And combine that with the fact that a razor's angle of attack is constantly changing as you move around your face and changes direction relative to the grain?

Do slants mainly benefit from a torqued/rigid blade instead of the guillotine effect? Discuss.

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#2

Member
Idaho Falls, Idaho
Wow! I wish I could discuss but I have no slants. Always meant to pick one up but never have. That said, I do use a technique called the Gillette Slide on a part of my face that seems to resist straight strokes. The Slide is holding the razor head at an angle when making a stroke and for me it works. Is it due to more efficient, oblique cutting or is it due to how my beard lays in that area? Shoot, I don't know. Wish I was smart instead of so rediculously good looking.

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#3
I'm subscribed because I'd like to know some of the questions. Good one Lipripper660, haha

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#4
Here is an old thread from B&B forum, 'Geometry of the Slant'. It's as good as any explanation I've run across. (I'm assuming it is legit to post a link to another forum ?) 

https://www.badgerandblade.com/forum/thr...ost-222280

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#5

Posting Freak
Canada
The only thing that I know and understand is that slants absolutely do not work, for me, unfortunately Smile

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Celestino
Love, Laughter & Shaving  Heart
#6
(This post was last modified: 01-20-2020, 04:09 PM by surfboat.)
(01-20-2020, 03:11 PM)JimmyH Wrote: Here is an old thread from B&B forum, 'Geometry of the Slant'. It's as good as any explanation I've run across. (I'm assuming it is legit to post a link to another forum ?) 

https://www.badgerandblade.com/forum/threads/on-the-geometry-of-the-slant.18255/#post-222280

B&b thread doesn't really address the original question. It's not like any substantial length of the blade contacts any single follicule. Therefore not much slicing is taking place. Remember surface area is relevant here.

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#7
(01-20-2020, 01:48 PM)Lipripper660 Wrote: Wow!  I wish I could discuss but I have no slants.  Always meant to pick one up but never have.  That said, I do use a technique called the Gillette Slide on a part of my face that seems to resist straight strokes.  The Slide is holding the razor head at an angle when making a stroke and for me it works.  Is it due to more efficient, oblique cutting or is it due to how my beard lays in that area?  Shoot, I don't know.  Wish I was smart instead of so rediculously good looking.


I tend to think the slide has more do so with how the hair lies, but for the sake of argument I could pose the same question. Given how thin hair is, is there a substantive change in surface area given an oblique cut? key word being substanitive. 

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#8
(01-20-2020, 03:11 PM)JimmyH Wrote: Here is an old thread from B&B forum, 'Geometry of the Slant'. It's as good as any explanation I've run across. (I'm assuming it is legit to post a link to another forum ?) 

https://www.badgerandblade.com/forum/thr...ost-222280
Just curious Jimmy if you had any experience or luck with slant, cuz I haven't had the opportunity yet.?
#9

Super Moderator
I've got some slants and like the iKon 102 best.  The whole guillotine theory is compelling and your mathematical formula interesting, however, don't you have to account for the angle of the blade, sharpness, length etc?  I would assume that there is an optimal angle.  I'm sure the French worked it out buy trial and error  Confused  

In any case, the 102 works well as long as you're not trying to shave off a few days worth of growth because then the longer hairs tend to plug it up.  I'm also cognizant of the fact that I rarely perform a totally straight pass so that the actual angle vs the theoretical angle varies significantly.  The best thing to do is to give a slant a try.  There are a few out there and while I haven't tried them all (yet) as mentioned above, I find the iKon 102 to be most comfortable and efficient.

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#10
My preference is toward very efficient razors so I picked up a few slants to see how they perform. I’ve got a Wunderbar, German 37, and an older Hoffritz slant.

I never could fall in love with my them but here’s my thoughts which may very well be nonsense after only one cup of coffee this morning.

DE blades are pretty thin and meant to bend but the problem is that even the most rigid blade holding design still has to allow a certain amount of exposure where the blade is unsupported so the blade can cut hair efficiently. Gap also affects efficiency but I don’t see it as relevant here.

In my experience and in my mind, a blade with the same exposure that is torqued in a slant should be more rigid and cut with less resistance due to it being less likely to flex or get hung up on thick growth. The thickness of the hairs being cut definitely comes into play here, which of course varies.

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