Thread: Fin: fact or fiction?

I didn't vote. The existence of the undefined term "fin" cannot be trued or falsified by an election.

There are empirical facts:
Fact 1.
I have been honing exclusively with hones for quite some time (I'm not opposed to pastes as such, but I'm not using them for now). After my honing, I always perform the HHT. Regardless the value of that test for predicting shaveability, the HHT always improves after I strop the razor on clean leather. Stropping does something with the edge, that makes it sever a hair better. It requires a certain amount of stropping, but after that, more stropping doesn't make a difference.

Fact 2.
Stropping a used razor, repairs something at the edge, that got lost during the previous shave.
I oil my razors after each shave, so this can't be about removing corrosion.

This causes me to speculate that there's a small part of the edge, that can be influenced by the kind of draw and friction provided by a leather strop.
I extracted a picture out of Verhoeven's paper and would like to cite it, with reference to the original article (http://mse.iastate.edu/fileadmin/www...nifeShExps.pdf)


Both right pictures show a bur-like part at the very edge, that looks like silver lining.
It is a picture of a straight razor's edge. Verhoeven reports it was honed and stropped by one Mr. William Dauksch, a long-time straight razor user. He also reports that the edge showed some roughness on higher magnification pictures that are not included in his document. As we can see at the far right picture, and I believe also in the left (3000X) picture, it was not the very best stropping job. Part of the edge is a bit fold over, and the alignment (in the left picture) is not excellent.
Even so, I would like to define the part of the edge, that can be affected by stropping as the "fin". I have used the word "fin" in that meaning in some of my recent posts. I have been speculating that the "fin" part of the edge exists of steel that has underwent some alterations to the original hardness and structure of the steel, which influences the longevity and "stroppability" of the razor. There are scientific studies that point in that direction.

With regular knife and tool sharpening, we usually hone till a bur grows so large that it starts folding over, and we can feel it to the touch. Then we hone the other side, and finalize the sharpening session by dealing in some way with that bur. While honing straight razors, we flip the razor with each stroke. That keeps the bur small, but not non-existent.

In my opinion, that bur, aligned in the right direction to be part of the edge, is " the fin".
In that respect, I agree with many things presented in this thread by Afdavis and English.

Bart.

Depends on how you're envisioning the "fin". I think you're implying that the "fin" section of the edge has less of an angle than the main portion of the bevel (the "Y" shape"). Consider that the "fin" in the pictures may have MORE of an angle than the main portion of the bevel.

1) Surely there is some abrasive quality to a strop. There is *some* abrasive quality to any material. Couldn't you explain the pictures just as well by speculating that the fine silvery edge you see is simply a "double bevel" created by stropping? The leather strop being supple would be deflected a bit by the edge and have more of an angle than the more rigid surface of the hone. The angle of the "fin" would be greater in that case.

2) The bevel will have decreasing "structural capacity" (<-- descriptive term) as the cross section narrows moving towards the edge. Cutting hairs and just running the blade across your skin will do some damage. Stropping it (see 1. above) could repair this to some extent.

I believe everyone is using the term "fin" to describe some portion of the edge that has significantly less angle than the bevel. The "Y" shape. Some flexible/floppy flat piece of steel extending significantly further from the edge than the point where the two sides of the bevel would meet. I'm not buying it.

Originally Posted by Quick

Depends on how you're envisioning the "fin". I think you're implying that the "fin" section of the edge has less of an angle than the main portion of the bevel (the "Y" shape"). Consider that the "fin" in the pictures may have MORE of an angle than the main portion of the bevel.

No, I'm not defending the Y-hypothesis. I think the very edge (why not call that part "fin"?) is always convexed. But it's so thin that it bends and looses alignment from use.

Originally Posted by Quick

1) Surely there is some abrasive quality to a strop. There is *some* abrasive quality to any material. Couldn't you explain the pictures just as well by speculating that the fine silvery edge you see is simply a "double bevel" created by stropping? The leather strop being supple would be deflected a bit by the edge and have more of an angle than the more rigid surface of the hone. The angle of the "fin" would be greater in that case.

Sure, I'm not denying any of that.

Originally Posted by Quick

2) The bevel will have decreasing "structural capacity" (<-- descriptive term) as the cross section narrows moving towards the edge. Cutting hairs and just running the blade across your skin will do some damage. Stropping it (see 1. above) could repair this to some extent.

My point exactly.

Originally Posted by Quick

I believe everyone is using the term "fin" to describe some portion of the edge that has significantly less angle than the bevel. The "Y" shape. Some flexible/floppy flat piece of steel extending significantly further from the edge than the point where the two sides of the bevel would meet. I'm not buying it.

I'm not saying that either. But I do believe that the fin part of the edge (the part that's affected by stropping) has not the original steel structure, due to the physical processes present while honing and stropping. But even when you disagree with that, I still think "fin" is a valid linguistic term for "the thinest part of the edge". And that the special measures that part of the edge calls for, is the main reason why we use a clean leather strop.

I didn't vote because I have a problem with the terminology (sorta').
If the poll was reworded to this:

Burrs: Fact or Fiction? (public results poll)

• Micro-burrs are real and serve a purpose
• Micro-burrs are BS

...I would have picked door #1.

I believe that no matter how light your honing stroke is (assuming both bevels meet), you will form a micro-burr on the side opposite to your hone. I have no idea if this burr survives being stropped. I tend to think that it very well might. Or, even if it doesn't, is the strop re-applying a micro-burr at every stroke? Or just bending one back and forth?

A wire edge is an uneven burr that digs in and grabs unevenly. Maybe it's really a nice, consistent, more unbroken micro-burr (i.e. "fin") that passes the TPT when it grabs the meat so evenly.

Certainly is neat to debate and wonder about. Either way, I agree that the real answer won't change my honing much.

WONDER PHOTOS REVEAL UNSUSPECTED FACTS ABOUT Razor Blades and Shaving

Here are some pretty good pictures of the effect of stropping. It appears that stropping smoothes the edge. I don't see any real evidence of a "fin" type structure from these photos . . .

I'm a little confused by this thread, but that may have to do with my lack of expert knowledge.

I always thought the traditional explanation of plain stropping is that it smooths the edge, in other words aligns the "teeth" formed at the very edge by any honing medium's scratch pattern.

That it isn't abrasive enough to remove material would seem to be evidenced by the fact that no plain strop, no matter how old or how much it's been used, is darkened by steel particles the way pasted strops are. At least no plain strop I've ever laid eyes on.

The very edge of a well-honed razor is very thin and delicate, by definition. Just how delicate will vary according to the properties of the steel and the skill of the honer.

We can choose to think of this most delicate area, these teeth that get distorted or frayed by shaving, as a thing unto itself and name it a fin. Or we can think of it as simply part of the bevel, the most delicate part, and not call it anything special. But these are linguistic and conceptual choices, not empirical questions about whether something exists or is "magic." Right? Or am I missing something about the stakes of this discussion?

I think that is the way I see the problem. I think others are trying to negate the theory that there is an actual "fin" like structure that protrudes from the bevel.

I'm not sure that the "fin" is a physical thing (such as a protrusion) but more of a condition of sharpened steel.

So the argument may be about whether there is a "condition" at the edge of a bevel.

I think in the end we have to have a word for the sharp edge of the end of the bevel.

Alan, thanks for the link. Nice reference.

That article seems to make a lot of sense. (If I was gonna' vote, now I like door #2...)

Yea, I liked that article too. Its always nice when we have simple answers.

Originally Posted by dylandog

That it isn't abrasive enough to remove material would seem to be evidenced by the fact that no plain strop, no matter how old or how much it's been used, is darkened by steel particles the way pasted strops are. At least no plain strop I've ever laid eyes on.

I've always been under the impression that when you rub two things together they will both lose material. How much, is proportional to the relative difference in hardness.