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Your hair can crack steel

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Your hair can crack steel

Postby Pete Maddex » 01 Oct 2021, 11:50



Interesting...

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Re: Your hair can crack steel

Postby droogs » 01 Oct 2021, 13:24

Interesting indeed. Makes me glad I've had my razor for over 25 years, mind you it's had 743 new heads and 28 new handles. No it hasn't it's a nice Dovo cut-throat
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Re: Your hair can crack steel

Postby RogerS » 01 Oct 2021, 14:57

Wonder if it depends on what type of hair it is you're shaving ? :eusa-whistle:
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Re: Your hair can crack steel

Postby novocaine » 01 Oct 2021, 15:20

RogerS wrote:Wonder if it depends on what type of hair it is you're shaving ? :eusa-whistle:


I go through 40-50 blades a year.

but David, you have a beard..................... :shock: (why isn't there a vomitting emoji?)
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Re: Your hair can crack steel

Postby Andyp » 01 Oct 2021, 16:47

Philishave for me. Replaced the 3 rotary head once in 10 years or more.
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Re: Your hair can crack steel

Postby Trevanion » 01 Oct 2021, 20:48

They weren't using rounded bevels, obviously.
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Re: Your hair can crack steel

Postby droogs » 01 Oct 2021, 22:57

nor 2 pushsticks
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Re: Your hair can crack steel

Postby D_W » 12 Oct 2021, 16:51

Trevanion wrote:They weren't using rounded bevels, obviously.


Well, they weren't. If you use a straight razor, you do (at least if you use a linen and leather) if you do things properly.

The objective on a straight razor is to have an even edge that easily cuts hair, but doesn't cut skin on the back of the pore, and doesn't deflect.

This could be done on commercial razor blades, but it's not, and I don't know why. There's no great incentive for a razor blade maker to make a commercial DE blade that doesn't deflect, though, but there's much to make one with a slick coating on it (as in slippery, feels sharper even than it is- platinum or chromium) and a soft easy to process flexible stainless under it. That incentive is you remember that initial sharpness and have a positive thought about using another blade.

The revival of straight razoring has led to people sharpening straight razors to a very fine apex and then complaining that the razors don't hold their edges well, and then honing every two weeks. If you're using a linen and leather, you can hone for about 5 minutes with a fine stone once a year, as the linen and leather will modify the edge in a way that hair doesn't dent it.

This is the edge on my straight razor after about half a year of shaving (150x optical - the picture is about 2 hundredths of an inch tall or a little less).
https://i.imgur.com/NUudXa7.jpg

This is a commercial astra razor blade after two shaves.
https://i.imgur.com/BeOVEw0.jpg

(some people say these are good for two shaves, some say two weeks - I guess it depends on what you like). things go downhill at the edge after this and you can find larger damage. At this point, the straight razor cuts hair more easily even though it's been shaved with about 100 times and not rehoned.

Understanding this small modification to remove the apex that gets damaged can be applied to hand tools. There's certainly resistance to it. Less resistance to the cutting edge, though!

Every couple of years, an article comes out "true reason that razors get dull!!" that has some reasoning in it that researchers would provide, talking about bevel angles, etc. But this was solved long ago by allowing linen to establish the final edge on a straight razor and then advising with razor hones to avoid allowing the hone to get all the way to the edge and "overhone" the razor.

You can also create a very thin bevel very sharp but strong pocket knife edge, too, and knife edge, and on and on.

The second reason disposable blades appear to be dull (illusory) is if you use a DE or disposable razor and allow soap or dry lather to accumulate on the bevel just behind the edge. The edge will behave as if its very blunt, and once you wipe the dry soapy stuff off, it's fine.
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Re: Your hair can crack steel

Postby D_W » 12 Oct 2021, 17:13

Separately, you might recognize my user ID - I've been down the road eyeballing razor edges for about a decade to figure out how to get the damage to stop, and with a straight razor, avoid honing away rare solingen-foche razors that can't be replaced.

5 minutes per year with one inexpensive natural slate stone vs. 20 minutes every two weeks with a gaggle of synthetic stones is sort of an easy decision.

As is the case with woodworking, the shaving forums are quick to write off older processes as confusing and ineffective. It can be difficult to get good real linen that's not hard or scratchy, and the leather that was used in good strops is something that's not made similarly in the US now (shell from horses, but not the surface treated stuff that horween makes - btdt, the coating on the surface doesn't last. Something much more inexpensive from france or japan is the ticket).

When you put the pieces together, the trivial things that make stuff work like it was intended, suddenly it's not very difficult. But you (I) can't make much of a dent if the gurus advocate some other process ("honing pyramid processes", etc).

And when the next article comes out about how a razor blade actually dulls, I will get 10 emails from people (as I always do), "here's something you ought to know".
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Re: Your hair can crack steel

Postby Trevanion » 12 Oct 2021, 18:16

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Re: Your hair can crack steel

Postby Lurker » 12 Oct 2021, 18:18

:text-goodpost:
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Re: Your hair can crack steel

Postby TrimTheKing » 12 Oct 2021, 18:32

Welcome to the Haven D_W

D_W wrote:Separately, you might recognize my user ID - I've been down the road eyeballing razor edges for about a decade to figure out how to get the damage to stop, and with a straight razor, avoid honing away rare solingen-foche razors that can't be replaced.


That’s all very good and so long as it stays at eyeballing and doesn’t turn into evangelising about specific sharpening techniques then everything will be peachy.

That subject never leads to anything other than arguments and has long since been banished from this corner of the woodworking Internet. ;)
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Re: Your hair can crack steel

Postby RogerS » 12 Oct 2021, 21:58

TrimTheKing wrote:Welcome to the Haven D_W

D_W wrote:Separately, you might recognize my user ID - I've been down the road eyeballing razor edges for about a decade to figure out how to get the damage to stop, and with a straight razor, avoid honing away rare solingen-foche razors that can't be replaced.


That’s all very good and so long as it stays at eyeballing and doesn’t turn into evangelising about specific sharpening techniques then everything will be peachy.

That subject never leads to anything other than arguments and has long since been banished from this corner of the woodworking Internet. ;)


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Re: Your hair can crack steel

Postby D_W » 13 Oct 2021, 16:51

Well, it's not about a method - you can learn from the geometry and do anything you want to get it.

It's interesting that the topic was brought up (much like the cursory emails that I get), I gave an explanation for it (the rounded edge does actually exist on razors, and has for a while, and on the type where it's standard, there is no suffering of dullness).

The story suggests that "researchers didn't know this". This is unlikely, but it does make a good news story. The production of the razor blades studied is immensely complex, as is the metallurgy to get a stainless blade that has tiny carbides. The idea that gillette or anyone else has made razor blades (to be disposable) for more than 100 years and they never knew they failed by denting is pretty far off. All it takes is a very inexpensive visual top load microscope.

More than happy to not talk about sharpening techniques, though. The geometry itself may be useful - but you can get it any way you want. I used linen and leather on the razor edge above. I have also resharpened DE blades (no need to share the method, it's not worth the cost when an astra blade is 12 cents per), and did find that they can be made to do the same - refuse to dent with hair. But DE blades under the coating are too soft to hold a relatively shallow angle, so the denting comes with some dullness. The blades would need to be slightly harder (as in, impulse hardened on the tip, then fine honed slightly rounded and then coated). They would be sharp and hold up. And there is almost certainly literature in the engineering departments discussing this and measuring the resistance to severing hair.

But who is rewarded for selling a coated DE blade that lasts 100 shaves? Nobody
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Re: Your hair can crack steel

Postby 9fingers » 13 Oct 2021, 17:07

Hi D_W,
Reading your output I'm reminded of the quotation from one of your countrymen, Thomas Jefferson

"The most valuable of all talents is that of never using two (ten?) words when one will do."

Please do tell us about your woodworking projects and as pictures are worth 1000 words then please include some photos to save your typing fingers.

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Re: Your hair can crack steel

Postby TrimTheKing » 13 Oct 2021, 17:09

It's certainly an interesting topic D_W, but as you will know, one that, while interesting, can serve to cause unnecessary 'arguments' on woodworking fora which is why it's not quite banned, but we try and avoid it where possible.

Your point about the manufacturers knowing all about these issues is probably spot on, why would they make something that lasts longer? They'd have to charge a commensurate amount and people wouldn't pay it so it's common sense that they make a lesser product to keep their revenues turning over.

Interesting as it is, let's leave it there everyone, thanks. :obscene-drinkingcheers:
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Re: Your hair can crack steel

Postby D_W » 13 Oct 2021, 17:50

9fingers wrote:Hi D_W,
Reading your output I'm reminded of the quotation from one of your countrymen, Thomas Jefferson

"The most valuable of all talents is that of never using two (ten?) words when one will do."

Please do tell us about your woodworking projects and as pictures are worth 1000 words then please include some photos to save your typing fingers.

Bob


posted in a separate thread - more pictures, limited words.

I'll add my location to my profile - I just went through the TOS to make sure I don't run afoul of any other written rules.
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Re: Your hair can crack steel

Postby Richard » 14 Oct 2021, 20:10

9fingers wrote:Hi D_W,
Reading your output I'm reminded of the quotation from one of your countrymen, Thomas Jefferson

"The most valuable of all talents is that of never using two (ten?) words when one will do." Bob


In the field of educational theory and academic practice I think the motto is the opposite because verbosity, inaccessibility and obfuscation (bull manure) seem to be valued traits, i.e., 'never use one word where ten will do'. Slainte.
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Re: Your hair can crack steel

Postby RogerS » 14 Oct 2021, 20:54

Richard wrote:
9fingers wrote:Hi D_W,
Reading your output I'm reminded of the quotation from one of your countrymen, Thomas Jefferson

"The most valuable of all talents is that of never using two (ten?) words when one will do." Bob


In the field of educational theory and academic practice I think the motto is the opposite because verbosity, inaccessibility and obfuscation (bull manure) seem to be valued traits, i.e., 'never use one word where ten will do'. Slainte.


But I think you'll find that possibly, 'maybe' even, on the other hand there is a slim chance, perforce, that your prognostication as to the verisimilitude of the aforementioned assumption just, but only just, a slim chance even, may be in the affirmative.

AKA You're right. :lol:
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Re: Your hair can crack steel

Postby D_W » 14 Oct 2021, 22:24

Richard wrote:
9fingers wrote:Hi D_W,
Reading your output I'm reminded of the quotation from one of your countrymen, Thomas Jefferson

"The most valuable of all talents is that of never using two (ten?) words when one will do." Bob


In the field of educational theory and academic practice I think the motto is the opposite because verbosity, inaccessibility and obfuscation (bull manure) seem to be valued traits, i.e., 'never use one word where ten will do'. Slainte.


Don't make me send you 14 emails with pictures of planed surfaces and split silica particles, Richard!!
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Re: Your hair can crack steel

Postby D_W » 14 Oct 2021, 22:26

RogerS wrote:verisimilitude

AKA You're right. :lol:


verisimilitude....

you get a golden chisel for being the second person I've seen (other than me) use that word without referencing professional wrestling.
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Re: Your hair can crack steel

Postby Richard » 15 Oct 2021, 20:46

D_W wrote:
Richard wrote:
9fingers wrote:Hi D_W,
Reading your output I'm reminded of the quotation from one of your countrymen, Thomas Jefferson

"The most valuable of all talents is that of never using two (ten?) words when one will do." Bob


In the field of educational theory and academic practice I think the motto is the opposite because verbosity, inaccessibility and obfuscation (bull manure) seem to be valued traits, i.e., 'never use one word where ten will do'. Slainte.


Don't make me send you 14 emails with pictures of planed surfaces and split silica particles, Richard!!

There's a spam folder for that ... isn't there? Slainte.
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