Thread: Honing "Feel"

If we are taking a vote on the science I am in your camp. With the addition of water and pressure on the blade the physical characteristics are more akin to suction then particle attraction.

F=AP which is derived from the definition of pressure which is P=FA

where as a Force is created that increases the Pressure in an Area greater than the pressure outside of that Area. With a reduction of Force a vacuum is created when the atmospheric pressure is not reduced equivalent to the -F

Somewhat like a glass of cold water sticking to a table. Except with in that case the water creates a seal around air which is cooled causing it's atmospheric pressure to drop below that of the air surrounding the glass. Vacuum or low pressure.

In the case of the razor and hone, the honing pressure on the blade creates a drop in pressure below it. That area's low pressure = suck.

And ScoutHikerDad Theoretically, in QCD (quantum chromodynamics) vacuum multiple vacuum states can coexist. Where as the blade has a vacuum the sucks yours is just a matter of needing more practice :<0)

Originally Posted by razornut

Actually. I think it's more likely air pressure. When the edge is so smooth. That air can't leak past and the surface tension of the water seals the ends then a slight vacum is created. When that happens atmospheric pressure literally pushes the blade onto the stone.

Thanks for making me feel dumb on multiple levels, Pups.

Edit: FWIW, I got in plenty of practice over the weekend with 4 problem blades. I was up at Kevn/Hidestoart's house, and tweaked those blades out to the max on synthetics up through the Norton 8k, then a natural progression from coticule to escher, followed by lots of stropping on all his wonderful handmade strops. I brought those edges home, tested 'em out, and they're the best, smoothest I've ever shaved with. It was really my first good session with naturals, and I have to say I like those edges even better than the ones I finished on a Nani12/Gokumyo 20k progression at the Asheville meetup! Maybe there's hope for me yet.

See now, I was joking around but you out and out lied :<0)

Originally Posted by ScoutHikerDad

Thanks for making me feel dumb on multiple levels, Pups.

Edit: FWIW, I got in plenty of practice over the weekend with 4 problem blades. I was up at Kevn/Hidestoart's house, and tweaked those blades out to the max on synthetics up through the Norton 8k, then a natural progression from coticule to escher, followed by lots of stropping on all his wonderful handmade strops. I brought those edges home, tested 'em out, and they're the best, smoothest I've ever shaved with. It was really my first good session with naturals, and I have to say I like those edges even better than the ones I finished on a Nani12/Gokumyo 20k progression at the Asheville meetup! Maybe there's hope for me yet.

FWIW I bet your not so dumb either....

I'll chime in with my take on it - coefficient of friction.

As the surface of the bevel smooths out the coefficient of friction increases because there is more metal touching the hone than there would be with a rough edge.

This is analogous to steet tires with tread and track tires with no tread.

-john

If I might add
Strictly. Speaking. In nature there is no such thing as suction or pull other than the electro magnetic force. Air pushes and. Tries to get to an area of lower pressure, taking with it any thing that gets in the way. Be it a razor or a rug when hoovering. An old physics teacher said to me "a horse doesn't pull a cart. It pushes the harness around its neck. For some weird reason that ' STUCK' lol

Thanks to all especially for the science lessons. Seriously, many thanks for all your contributions it's reassured me that my honing is moving in the right direction. The point about the scratchy feel moving to smooth also makes sense. I've checked an old razor I honed some time ago and compared it with my recent efforts with a loupe. Now I can not only see the difference, there being far less scratches, but also feel the difference, particularly on the higher grit hones. I'm finishing on a SG 16k but have also done a couple after that on a ZG, not sure yet if that's the way to go or just move from the SS 12k to either the SS or the ZG and not both. So the experimentation continues!
Again, thanks to all.

All right people, thanks to all of your wonderful contributions, and for the sake of correct scientific behaviour, which means reviewing your hypothesis, let me propose another, probably more consensual explanation.

Let's keep it short, wetting (warning, advanced science happens on this wikipedia page) seems to be a very strong candidate for a correct answer.

To the point :
- the flatter a surface, the harder water adheres
- the flatter/thinner a water drop, the stronger it sticks

Conclusion :
if you have a very smooth and flat surface (high grit whetstone) and your blade is sufficiently flat and smooth, then they French kiss and get stuck because of the saliva

Conclusion in simple terms :
Succion good, because very flat and smooth everywhere, water happy

[long and boring]
My initial hypothesis was that two sufficiently flat surfaces, such as calibrating tiles in metrology, adhere to each other thanks to Van der Waals forces.

Such an adhesion can only be broken by sliding the tiles, much like on very high grit stone the smaller stone is sometimes "stuck" to the larger one and can only be removed by sliding.

That would stand true, and may be an underlying cause for wetting (not a specialist actually), but actually if that really was the case, you would feel succion even on a dry stone, which is not the case : water is an essential element.

I pondered also on the venturi effect (the actual name of the phenomenon 10pup refered as succion), but this effect is strongly affected by speed, which in my experience does not have any effect on how much the stone sucks the blade.

The actual mechanism may be far more complicated and may include also things like surface tension
[/long and boring]

Nobody really knows why two very very flat surfaces stick together. Nobody has ever bothered to investigate it in depth I think. There have been several theories that have settled out as most likely. Some say Van der Waals forces, others the atmospheric/pressure thing, others think it's microscopic contaminants such as oil or humidity in the air. Maybe a combination? All I know for a fact is that once two surfaces are flat enough, they can stick together with very significant force. One good example I can give from the machining world is what are known as "gage blocks." These are dimensionally accurate steel, ceramic, or tungsten carbide blocks that have been lapped to super fine and extremely flat surfaces. They are used for inspection and measurement down to .0001" and here's the kicker: you can take two of the blocks when in good condition with no scratches or other blemishes and clean them with acetone and a lint-free cloth so that there is no oil or any type of contaminants on the surfaces and stick them together with a slight twisting motion and they will stick like they're glued. If you try to pull them apart in a straight opposing direction (i.e. no angular motion or twisting) they will hold quite fastly. Some of the old advertising materials for certain brands of the blocks would hang quite a bit of weight from one of the blocks like in the old crazy glue commercials to demonstrate their holding power and hence flatness. When assembling them for measuring they are put together like this - it's called "wringing" and there is a defined amount to add to the length of the block stack for each wrung joint (though it is mostly included in the block's advertised length, so it is compensated automatically), so the surfaces are not considered to make perfect and full contact even though they are as flat and smooth as the dickens. Once there is any surface defect or they aren't nearly perfectly flat anymore they will not wring together properly anymore. I have a set I use for dimensional inspection.

Here's a link to one manufacturer's explanation:

Wringing Gage Blocks

I can give from the machining world is what are known as "gage blocks."

Ah, many thanks, could not find the exact term to what I was refering in the previous post as "calibrating tiles in metrology"

They indeed were what I had in mind when I developped my first explanation. I was told at the time it was due to Van Der Waals forces (ingeneering scholl), it's interesting to know the explanation is not that simple.

Still, I stand by the fact that after much pondering, such may not be what happens in the current case. The main reason behind that being that a dry stone does not suck a razor's edge, AFAIK (or at least, not at the grits I am accustomed to).

Therefore my conclusion that the phenomenon known as "wetting" my be a stronger candidate for the correct explanation.

Fascinating discussion, heartfelt thanks gentlemen

I have to admit I do like the idea of a low pressure being created by perfectly flat surfaces. The same effect would apply (to a lesser degree) to a surface that has some sort of wetting agent between it to compensate for imperfections. The low pressure would then create a suction effect because, in order to seperate the two flat surfaces you would have to overcome the force of the displacement of air between the two surfaces. The whole subject is a bit of a mind warp though.