How does honing speed affect a razor?

[Legion]

It seems then that the empirical/anecdotal evidence here is that speed doesn't make a difference, if all other things are equal.

So can anyone who knows about physics n stuff tell me why? Why does the momentum or kinetic energy of a razor across the surface of a stone not have a noticeable impact on the outcome...?

I think a better question is, why would it make a difference? It seems to me, the honing effect is achieved by two factors, pressure and the amount of rubbing that takes place. If the hone size doesn't change, the number of laps is the same, and the pressure is equal, then fast or slow should not change the outcome (unless you are going so fast as to generate heat, which is not going to happen by human hands on a wet stone)

 

[Tomo]

I don’t have any tests or evidence to back it up but my view is that the honing results would start to suffer at the extremes. I aim for a nice, smooth and steady honing stroke.

I can see how too slow could be a problem. Have you ever tried to draw a straight line freehand? If you do it slowly the line is bumpy and jagged. Much easier to do it quickly. I also feel like the blade will skate across the micro bumps on a hone more evenly with a bit of pace. To slow and you will feel every bump in the road.

I have noticed if I go too fast on water it’s possible to undercut the water completely and have it wash right over the back of the razor. I like to keep a little wake of lubrication going in front of the edge. It’s also hard to keep good control and balance at speed although theoretically it should be possible.

 

[cotedupy]

I think a better question is, why would it make a difference? It seems to me, the honing effect is achieved by two factors, pressure and the amount of rubbing that takes place. If the hone size doesn't change, the number of laps is the same, and the pressure is equal, then fast or slow should not change the outcome (unless you are going so fast as to generate heat, which is not going to happen by human hands on a wet stone)

Because at a very small level you're hitting against abrasive stuff while going sideways. Momentum will (I would have thought) affect that impact and the way it abrades or wears the steel to hone it. And momentum in this instance is going to be pressure down x speed. If sharpening was only about pressure down, rather than directional force, then there would be no difference between leading and trailing strokes, you could rub your razor on the stone in any direction or motion you like and get an identical outcome.

So, why doesn't it seem to make a difference? Am I all wrong on the physics? Can someone explain...?

 

[rbscebu]

It seems then that the empirical/anecdotal evidence here is that speed doesn't make a difference, if all other things are equal.

So can anyone who knows about physics n stuff tell me why? Why does the momentum or kinetic energy of a razor across the surface of a stone not have a noticeable impact on the outcome...?

Momentum and kinetic energy will affect the stopping distance at the end of each stroke. That is all it will do. It will not have an effect the result of the honing.

 

[JPO]

Because at a very small level you're hitting against abrasive stuff while going sideways. Momentum will (I would have thought) affect that impact and the way it abrades or wears the steel to hone it. And momentum in this instance is going to be pressure down x speed. If sharpening was only about pressure down, rather than directional force, then there would be no difference between leading and trailing strokes, you could rub your razor on the stone in any direction or motion you like and get an identical outcome.

So, why doesn't it seem to make a difference? Am I all wrong on the physics? Can someone explain...?

Your edge as it passes over a bumpy surface will act as a spring. When you increase the speed the impulse as you hit the abrasive particle increases. Think of the springs on your car. If you increase the speed and pass over a bump the impulse force in your springs will increase. With respect to honing, you should increase the cutting efficiency, in theory at least.

It’s been along time since since i opened my old physics books. Just thinking of differential equations makes my head hurt

 

[Steve56]

You might want to read the barbering chapter of Iwasaki’s book. Iwasaki recommended shortening your stroke and the pressure just melts away. But it occurred to me that with a short steoke/short hone, you. can’t hone as fast or you’d be running off the ends, or at least I would be.

 

[cotedupy]

You might want to read the barbering chapter of Iwasaki’s book. Iwasaki recommended shortening your stroke and the pressure just melts away. But it occurred to me that with a short steoke/short hone, you. can’t hone as fast or you’d be running off the ends, or at least I would be.

Ha! This is my no.1 problem with small hones. I lack patience.

 

[Steve56]

I heard that patience is a virtue somewhere, lol.

You have to have more patience (and coarser stones) when honing a straight razor because you can’t push very hard on it.

 

[cotedupy]

I heard that patience is a virtue somewhere, lol.

You have to have more patience (and coarser stones) when honing a straight razor because you can’t push very hard on it.

I know... and it's especially annoying because on a finishing stone I can't really tell how I'm doing as I go along! I might well have fecked everything on the first stroke and not know until ten excruciatingly slow minutes later .

 

[Steve56]

BTW, the patience and finesse that you learn by honing razors will transfer to at least some of your knife and tool edges (depending on how they’re made) and make them better, especially the fine Japanese.

 

[Steve56]

Oh, try honing on a large tomo nagura. You can certainly do it, but you’ll need small circle and/or ellipse strokes. It’s fun !

And it’s also the definitive test of your tomo nagura.

 

[Frank Shaves]

My guess is we all move the blade at different speeds depending on what we are doing. If you are using short strokes on a coarse stone to remove a chip, the blade velocity might be faster than using light x-strokes during the final laps on any stone in your progression. My stroke seems to accelerate more resulting in more velocity when I am "chopping wood" versus finishing up with shorter, lighter strokes. Gaining control, comfort and confidence are also factors.

 

[cotedupy]

Oh, try honing on a large tomo nagura. You can certainly do it, but you’ll need small circle and/or ellipse strokes. It’s fun !

And it’s also the definitive test of your tomo nagura.

Unfortunately I don't really have many Japanese razor stones, mine are mostly polishing stones. And the one I do have I bought by chance as a mystery $25 ebay stone that turned out to be a mizu asagi. Though there's a guy who lives near me who has a lot of Alex G's stones which he lends me from time to time, so next time I borrow a couple I'll give it a go!

---

I get the impression you and I probably like slightly different knife edges. Someone over on KKF recently observed that there was a current trend for mega-aggressive, low grit finishes, and I'm afraid I'm very much on that bandwagon - I almost always only use one or two stones in a progression. The large majority of knives I sharpen are for other people; either the Japanese knives I sell, or just other people's knives, and this kind of edge is a little sturdier.

The exception though, as you say, would be for my own collection of yanagi. I find the theory and techniques of yanagiba sharpening very comparable to razors.

 

[Steve56]

Similar roots for sure, tools, knives, razors, they were all made by blacksmiths (and still are). but as time goes on smiths get more specialized.

I like a ‘toothy’ edge for veggies like most everyone else, and a finer edge for meats. Suitas of differnt grits are hard to beat for kitchen knives unless you‘re in competition sushi. And maybe not even then. The problem of course is that suita are expensive stones.

You can get the same results with synths, on knives the difference doesn’t matter much - a pot roast never complains.

Lately I’ve tended to semi-stainless, R2, SLD, etc. I’m freakin’ tired of watetsu cladding a couple of thousandths of an inch thick that does nothing but stain food.

 

[Slash McCoy]

Similar roots for sure, tools, knives, razors, they were all made by blacksmiths (and still are). but as time goes on smiths get more specialized.

I like a ‘toothy’ edge for veggies like most everyone else, and a finer edge for meats. Suitas of differnt grits are hard to beat for kitchen knives unless you‘re in competition sushi. And maybe not even then. The problem of course is that suita are expensive stones.

You can get the same results with synths, on knives the difference doesn’t matter much - a pot roast never complains.

Lately I’ve tended to semi-stainless, R2, SLD, etc. I’m freakin’ tired of watetsu cladding a couple of thousandths of an inch thick that does nothing but stain food.

I have to agree. I do not have a single kitchen knife that cost over $14. They are all stainless except for my cleaver and my machete. I hone a few to 1k, and the rest I use a Lansky Quad-sharp pull-through, and I strop as needed with my butcher's steel. I could hone to 8k or 12k, and after the first few good cuts into cutting board, the edge will be pretty much indistinguishable from a 1k edge that has endured the same treatment. If I won't spend $600 for a razor, I certainly won't spend that for a kitchen knife, not being any sort of professional chef. And I am not going to spend $300 on a fancy rock to hone those knives. YMMV but to me it seems a waste of money that I could buy more beer ingredients and brewing equipment with, or ammo, or stuff for the boat, or taking Mrs. McCoy out for dinner, or buying a few more shares of TQQQ now that the price has probably hit bottom.

I don't believe better knives or better honing will make the food I cook taste, smell, or look, one bit better than it already does, nor would they be any easier to use. (Says the guy who really doesn't care whether he shaves with a Bergischer Lowe or a GD66)

 

[Steve56]

Slash, a lot of those cheap (but surprisingly good steel most times), old school knives just wedged food apart, if you looked at the apple, potato, squash, melon, etc, that were cut with them, you can confirm this. If your knife is a wedge, it doesn’t matter what it was finished with or how fine. In fact, you never had to sharpen one because the edge wasn’t doing anything anyway.

No offense, I grew up with these, know them well.

 

[thp001]

How many angels can dance on the head of a pin btw?

 

[cotedupy]

Similar roots for sure, tools, knives, razors, they were all made by blacksmiths (and still are). but as time goes on smiths get more specialized.

I like a ‘toothy’ edge for veggies like most everyone else, and a finer edge for meats. Suitas of differnt grits are hard to beat for kitchen knives unless you‘re in competition sushi. And maybe not even then. The problem of course is that suita are expensive stones.

You can get the same results with synths, on knives the difference doesn’t matter much - a pot roast never complains.

Lately I’ve tended to semi-stainless, R2, SLD, etc. I’m freakin’ tired of watetsu cladding a couple of thousandths of an inch thick that does nothing but stain food.

Yeah, about the only Japanese stone I use for sharpening is a lovely Maruoyama S Suita. Though it's still more of a polishing stone for me; for work I probably use SG500, Washitas and Turkish more than everything else put together.

 

[cotedupy]

How many angels can dance on the head of a pin btw?

That's a whole different thread!

 

[cotedupy]

Slash, a lot of those cheap (but surprisingly good steel most times), old school knives just wedged food apart, if you looked at the apple, potato, squash, melon, etc, that were cut with them, you can confirm this. If your knife is a wedge, it doesn’t matter what it was finished with or how fine. In fact, you never had to sharpen one because the edge wasn’t doing anything anyway.

No offense, I grew up with these, know them well.

Nothing tastes as good as skinny feels.

Thinning Knives

'Nothing tastes as good as skinny feels.' - Kate Moss, 2009 --- This post is going to look at hows and whys of thinness in knives. As well as touching on the reasons that, above and over anything else, you probably want to get a coarse-ish whetstone for kitchen knives, and the drawbacks of...

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