Thread: My razor is too sharp???? I like a duller edge??

I think what we're arguing about is really just definitions.

Originally Posted by gssixgun

Ok there is where ya lost me,,,
Anything in the finishing stages is about finishing not about sharpness...
You are talking again differences in the 1/1ooths of a micron on any given razor.... If you go farther the edge fails and you get a harsh shave....

You know exactly where and how far to take an edge, I am pretty sure of that, I would never push a maxed out edge either...

This gets back to the two definitions of sharpness. Anything after about 4k is about finishing not sharpness across the bevel. If you use a coticule then you're talking about finishing and not sharpness across the bevel. If you believe that the norton 8k produces a sharper edge than the 4k or that the coticule produces a sharper edge than the norton 8k then you're also talking about that looser definition of sharpness that i'm calling "percieved sharpness".

I'm not talking differences in the 1/100ths of a micron of the edge. The edge just doesn't get any sharper - the steel just can't handle being that thin and crumbles away like a cliff edge, whether you're at 4k or 30k - the edge is the same thickness across. going to too high a polish doesn't make the edge fail - it's been failing since you left the 4k hone. What is different is the polish on the bevel behind that broken edge of steel, and that affects the cutting friction. At some point if the cutting friction gets too low it gets to the point where the blade has too easy of a time cutting through the skin, and the blade feels harsh. The feather ac does this with a coarse honing and a generous coating of teflon. My sharp edges do this with a fine honing and a good polishing on 0.1 micron diamond. I don't like that, so I don't do it anymore.

If you don't use 0.25 or 0.1 micron diamond because you think it makes the edge too harsh, then that's exactly what I'm doing when I hone my edges to a slightly dull level. You're calling it avoiding overhoning, I'm calling it less sharp. This is probably due to our two differing views as to what constitutes sharpness, but we're doing the same thing we just have different theories as to why.

I'm quite sure that they are nearly exactly the same width across the bevels. Verhoeven demonstrated that the limits for the edge width arrive at a surprisingly low abrasive grit, something around 4k or so, and that going up to 8000 grit and higher (he went up to 0.5 micron chrome oxide) doesn't change this fundamental sharpness.

So why do you hone your razors beyond 4k? Why use the yellow side of the norton, or a coticule or escher. Why do people argue about which gets a sharper edge, when the edge isn't getting any sharper? Something else is being done to that edge, something besides making it sharper. Something that doesn't make it sharper as measured across the bevels, but makes it feel and act for all the world as if it were sharper.

Exactly!!! Thank you, Discussion done...

Sharpness is one aspect, and smoothness is another....

The actual thickness of the edge is sharpness, how it feels on your skin is smoothness...

This is what I have been saying all along, any more talking on my part and I will sound like that guy that doesn't like the word "Splash"

Semantics, indeed.

Against better judgement, allow me to stick my nose in that wasps nest...

In my daily recurring pondering about razor edges, I differentiate in my mind between a few terms:

-Sharpness: how easily the edge can cleave (a whisker, in our cause): Both "keenness" and "jaggedess" contribute to "sharpness".

-Keenness: how thin the line is where both bevel sides meet each other.

-Jaggedness: microscopical irregular projections and indentations at the very edge (sawtooth patterns if you wish) add considerate penetration ability.

For some examples:

-The DMT1200 edge, which is very sticky on both the TNT and TPT and easily pops a hanging hair, lends it sharpness on plenty of jaggedness and reasonable keenness.

-The completed bevel on a typical Coticule with slurry feels less sticky on TNT and TPT, and does not pop a hanging hair. There is no jaggedness to aid the keenness.

-Often, progressing to a finer step in a setup of synthetic water hones, makes the edge appear less sharp after the first laps. I believe this is because the jaggedness disappears before the keenness catches up after doing some more work.

Now, as far as "too sharp" is concerned. I believe people sometimes say this when the edge is too harsh. Harshness, I believe is caused by jaggedness, even if this occurs at micron level.
"Too sharp" can also mean that the person using the razor, is used to shaving with and edge that is more forgiving to applied pressure or an edge that allows for a steeper shaving angle or an edge that sustains pronounced scything motions without sinking into the skin.

This I gotta hear, PLEASE somebody tell me how to hone my razors to a slightly duller edge???

A few weeks ago I honed a razor for SRP-member Bromion, after he posted about ongoing irritation issues.
I first honed my usual routine. Shaved 4 full passes (1 WTG, 1 XTG and 2 ATG) with that razor, something I never do otherwise. Paid attention to the sting of the alum block. Before the next test shave, I toned down the edge a bit with 10 laps on a Coticule with very light slurry. (I know this brings the keenness down a bit).
Payed attention during the next test shave (again 4 passes) if I didn't went overboard. The razor definitely felt different, not as effortness, but certainly not pulling either. But: no sting on the alum whatsoever this time. That's how I send the razor to Jason.

I salute the guys from the Shapon 30K experiment. I love what they're doing. But I 'm not into shaving with feather light touch myself. I believe it's great that there are all these different preferences in razors, hones, pastes and the edges rendered by all the variables. Isn't that one of the things what keeps us all coming back to SRP?

Bart.

Originally Posted by gssixgun

I'm quite sure that they are nearly exactly the same width across the bevels. Verhoeven demonstrated that the limits for the edge width arrive at a surprisingly low abrasive grit, something around 4k or so, and that going up to 8000 grit and higher (he went up to 0.5 micron chrome oxide) doesn't change this fundamental sharpness.

So why do you hone your razors beyond 4k? Why use the yellow side of the norton, or a coticule or escher. Why do people argue about which gets a sharper edge, when the edge isn't getting any sharper? Something else is being done to that edge, something besides making it sharper. Something that doesn't make it sharper as measured across the bevels, but makes it feel and act for all the world as if it were sharper.

Exactly!!! Thank you, Discussion done...

Sharpness is one aspect, and smoothness is another....

The actual thickness of the edge is sharpness, how it feels on your skin is smoothness...

This is what I have been saying all along, any more talking on my part and I will sound like that guy that doesn't like the word "Splash"

I'm not saying that at all. The actual thickness of the edge is only part of sharpness. It determines the amount of resistance the blade feels to break the surface of the whisker or skin. But the other part of sharpness is the cutting friction, which determines the amount of resistance the blade feels to separate the whisker or skin apart. You would think this would be minor, but if you've ever used a splitting wedge to break up firewood then you know that this is actually a pretty major factor, and whiskers are even tougher than wood.

The commercial blade manufacturers lower the cutting friction by coating the blades in teflon. We lower the cutting friction by polishing the cutting surfaces with high-grit hones. This changes the percieved sharpness of the razor, and I guess correlates with smoothness as long as the resistance is still high enough. Teflon seems to lower it too much for an unguarded blade, while reasonable levels of polish are just right, and for a straight razor shaver offer him a greater degree of control over the resulting level of "perceived sharpness" since he values the honing time less than the commercial razor manufacturers. But it's not a perfect correlation with smoothness - there are other factors that affect smoothness, such as bevel angle, presence of different size scratch patterns, etc. And I can have a beautifully smooth-shaving razor that is nonetheless too sharp for comfortable daily shaving - I did this for many months when I was playing with newspaper, before I decided that there really was a limit the level of sharpness I preferred.

Bart's Sharpness, Keenness and Jaggedness are useful terms.

Originally Posted by Bart

... Both "keenness" and "jaggedess" contribute to "sharpness"

Using these terms, I think I am quite willing to lower my jaggedness score even though this will lower my sharpness.

I don't like dull. Give me scary sharp. I'm still learning to hone and I want to to really learn to refine an edge as close to perfection as possible.

There's another disadvantage of "too-sharp" edges. The stubble comes back spiky like it does with a DE. Wifey doesn't like that. "Slightly dull" edges produce stubble that comes back softer, not so scratchy.

I have a theory as to why this is, based on the theory of sharpness being a combination of penetrating resistance (determined by the edge width) vs cutting friction (determined by teflon/polish).

Originally Posted by gssixgun

Exactly!!! Thank you, Discussion done...

Sharpness is one aspect, and smoothness is another....

The actual thickness of the edge is sharpness, how it feels on your skin is smoothness...

I respectfully disagree with that.

I am a HHT-ing guy, and I'm rather thorough about objectizing that test. Each time I hone a razor, I observe how the keenness keeps improving till the very last stroke of the honing job. And then some during stropping.

It may be that the finishing hone only squeezes 0.05 micron of the width of the edge. But 0.45 is still 10% keener than 0.50. At the same time, that 0.05 micron means far less if you're still at the 1 micron level (the notorious newbie error of jumping into finishing mode too soon).

"Smoother" is another ambiguous term. If the blade severs the hairs easier, most people will qualify that as "smoother."
I believe many of the pastes are considered "smoother" because they render the edge a tad keener.
What I only partially buy, is that "better glide" theory.
A razor does not cut with less effort because it glides better through the whiskers. It does not need to glide through the whiskers. They're not a block of cheese where the knife needs to still pass through after the cut. The only glide we need is glide over the lathered skin. I don't think we are able to discern much between the different levels of polish we put on the bevel of a razor. I do think teflon fills the scratches, reducing jaggedness of the edge, and therefor reducing the damage to the skin. It irritates less, which also could be called "smoother".

Bart.

Originally Posted by mparker762

There's another disadvantage of "too-sharp" edges. The stubble comes back spiky like it does with a DE. Wifey doesn't like that. "Slightly dull" edges produce stubble that comes back softer, not so scratchy.

I have a theory as to why this is, based on the theory of sharpness being a combination of penetrating resistance (determined by the edge width) vs cutting friction (determined by teflon/polish).

And I thought I was done with this

I absolutely positively disagree here, "for my face" the sharper/smoother the edge the lighter the touch the lighter the touch the smoother the stubble feels growing back... That sharp stubble feeling for me along with the irritation that follows, comes from pressing the edge into the skin and cutting the hair at more of an angle....Or using a not sharp enough blade....

Originally Posted by Bart

What I only partially buy, is that "better glide" theory.
A razor does not cut with less effort because it glides better through the whiskers. It does not need to glide through the whiskers. They're not a block of cheese where the knife needs to still pass trough after the cut.

I hate arguments by authority, but the commercial razor blade manufacturers disagree with you. The friction i'm talking about isn't the friction between the whisker and blade after the whisker has been severed - its the friction between the whisker and blade while it's still being cut, as the blade is forcing the whisker apart. The initial effort to separate the strands of fibrin is determined by the edge width, but the whisker is as much as 180 microns across, so the two halves of the whisker are riding up the bevel quite a ways, and the whisker in front of the cutting edge is being stretched as the blade is forcing the two halves apart, acting like a spring and pulling the two halves tightly against those bevels. This can cause substantial friction, and substantial resistance.

Originally Posted by Bart

The only glide we need is glide over the lathered skin. I don't think we are able to discern much between the different levels of polish we put on the bevel of a razor.

Of course we can. The edge doesn't get any sharper past about 4k, but the bevel gets more polished. The commercial guys stop honing at some coarse grit, but that teflon makes all the difference in the world. And schick's "making of the modern blade" article makes it clear that the do it for sharpness, not smoothness.

Originally Posted by Bart

I do think teflon fills the scratches, reducing jaggedness of the edge, and therefor reducing the damage to the skin. It irritates less, which also could be called "smoother".

I disagree. A few years ago after I first read the Verhoeven paper I was looking into the whole sharpness question, and trying to figure out what the commercial guys knew about it, and ran across the patent for teflon coating razor blades. That patent claimed that the teflon coating was just a few tens of nanometers thick (i.e. too thin to fill in or reduce the jagginess of anything), and that the stress of shaving caused it to peel off of the cutting edge nearly instantly. Over the course of multiple shaves the peeled area would gradually increase until it was no longer effective.