first sharpening video! (and water stone review)

[BluntCut MetalWorks]

I've noticed he doesn't use the 'S' move all the time and figured it was to prevent the grind path from becoming parallel or reverse to the cutting edge - as will happen at the tip/belly when edge trailing, esp if you normally keep the edge at an angle to the grind/polish path. In his straight razor video he doesn't use the 'S' at all to speak of. In his "push cutting toilet paper" vid you can see what I'm describing. The 'Outdoor' model he's sharpening only has a little belly = smaller 'S'. Contrast that with this demo - you can see it very clearly at about 2.5 minutes, using a knife with a little more belly = larger S.

http://www.youtube.com/watch?v=5stV_1kID-U

At least I'm pretty sure that's what I'm seeing - hope so 'cause that's how I do it...

It makes a big difference on blades with a lot of curve - more consistent edge all the way to the tip. I barely use it all on knives like Mora and others with a shallow belly, have to really exaggerate on things like Bolo or Panga pattern machetes.

:thumbup: this is skill forming.

I'm thinking outloud with constructive intention.

Skill = what+why+how.
e.g. for the 's' stroke
'how'=no s, small s, big s + pressure @ grit -> incomplete
'what'=taken place, interaction (sharpening/honing/lapping/polishing) -> incomplete
'why'=prevent the grind...+follow the belly... however ain't so sure eh -> incomplete

This thread presents many good techniques(a set of 'how') + experiences. Add 'what'+'why' explanation, which lead to permanent skills. I afraid the complex interaction between blade vs [embeded abrasives, loose abrasives, swarf, pressure, edge trail+lead,...] deem quite voodoo outside of the sharpner-knut world.

 

[HeavyHanded]

This thread presents many good techniques(a set of 'how') + experiences. Add 'what'+'why' explanation, which lead to permanent skills. I afraid the complex interaction between blade vs [embeded abrasives, loose abrasives, swarf, pressure, edge trail+lead,...] deem quite voodoo outside of the sharpner-knut world.

Lol. Voodoo is a good descriptor! As Knifenut pointed out, adding just a little too much water to the mud at the wrong point can change your outcome considerably. Amounts of mud, slurry, swarf, and free water all have an effect. Of course you can always just use as a regular stone by rinsing often and not using the mud, but it can whip up some real desirable results, and where's the fun in that!

Add that different brands have different characteristics - many not so subtle, so learn on one brand of stone and you know that brand. General trends seem to follow across the spectrum, but a new learning curve for every brand you attempt. You can get gain a working knowledge fairly quickly, takes a while to "know" what you're doing.

 

[Rick Marchand]

You will develope your technique as you go. The only pointers worth sharing at this point are...

1. Use trailing strokes... don't use leading strokes on a waterstone.
2. You are over-sharpening without checking your progress enough.
3. Lose the loaded strop block.

 

[BluntCut MetalWorks]

You will develope your technique as you go. The only pointers worth sharing at this point are...

1. Use trailing strokes... don't use leading strokes on a waterstone.

Respectfully disagree - I don't have video convince otherwise but here is the link where John Broida of JKI sharpning on a 15K grit waterstone - employed both lead & trailing strokes. I like John's sharpening skills & styles. I slowly acquire skills and distill my own styles.

http://www.youtube.com/watch?v=g80n6hD-AUM&feature=plcp

 

[Rick Marchand]

Respectfully disagree

It's cool... we don't have to agree... that's the fun part of this craft.:thumbup:
Once you get above 8000 grit it is quite possible to do leading strokes with light pressure and good form. My experience has taught me not to do that anymore.

I tend to stay out of the sharpening threads as it can be a very individual "sport". I used to be very particular about my edges but these days, I only need the blade to perform well. Magnanimous looks as if he is off to a good start and I urge him to explore and develope HIS own style. Don't get hung up on what folks show or tell you until you are beggin the question. There is no sense in looking at micrographs and magnified edges when you are still working on form and motion.

 

[HeavyHanded]

You will develope your technique as you go. The only pointers worth sharing at this point are...

1. Use trailing strokes... don't use leading strokes on a waterstone.
2. You are over-sharpening without checking your progress enough.
3. Lose the loaded strop block.

1) Agree, except when grinding a new apex - otherwise edge trailing to finish. The Norton watrerstones are very aggressive and don't (for me) work very well edge leading either. The Kings OTH function far more like a normal whetstone.

2) Agree

3) Agree, the largest benefit of waterstones IMHO is freeing yourself of loaded strops, tho some plain leather or paper as a final polish works great!

Folks have to understand what they're doing with a ton of observation. As with other skills - mimic those that have the skill you want, understand why they do what they do, adopt your own style, keep an open mind. You will progress.

 

[Magnaminous_G]

I tend to stay out of the sharpening threads as it can be a very individual "sport".

Yeah, but that's BF, Rick. You've got a sharpening video that helped me a lot with my technique, and I know what kind of knives you are capable of making, so you'll always get full respect and consideration from me.

On the subject of stropping, I was looking at the kangaroo leather strops with glass backing. Those look very nice, but they're probably for people who can seriously refine an edge on the stones. With my final edges, I'd probably be wasting my time on plain kangaroo leather. But I think I'm gonna try the newspaper. Question for you: strop on dry or wet newspaper?

 

[Rick Marchand]

1) Agree, except when grinding a new apex - otherwise edge trailing to finish. The Norton watrerstones are very aggressive and don't (for me) work very well edge leading either. The Kings OTH function far more like a normal whetstone.

It may very well be the stones I have been using. That sounds reasonable.

3) Agree, the largest benefit of waterstones IMHO is freeing yourself of loaded strops, tho some plain leather or paper as a final polish works great!

I use wet newspaper:thumbup:

You back up your opinions with cold, hard evidence of skillz.

Yeah, but truth and the facts can sometimes be a bummer or just plain boring. I have been disappointed many times in the quest for knowledge... even when it has benefited me. Hype is a hell of a drug.

... should the newspaper be dry or wet?

Murray uses dry newspaper... I prefer wet. My test for whether or not to use coolant is to slide my finger rapidly along the surface of the abrasive... if it generates heat, I need liquid coolant. Dry newsprint generates heat. Maybe it is simply a matter of managing speed... maybe not. Roman Landes ran experiments with micro thermocouples inbedded in the very edge of blades being sharpened. Lightly dragging a blade along a dry stone generated temperatures in excess of 2000F. Loaded strops weren't much different. It was super-tempering the last few microns of steel at the edge... probably not noticeable in a woods chopper. I have to admit that his experiments had me wondering about what happens to the temper during a regular cut in wood, paper, etc... that has got to be generating heat as well?

Found it... Turns out it wasn't Roman's experiment but one he found in text...

I had a book dedicated to general grinding methods, in this book i found a test application.
A normal steel block apx. 2"x2"x4" that had a large number of highly sensitive thermocouples integrated in the surface.
The block was slid dry by hand over a 1000grit grinding paper.
The peak temps measured, walked up to 2000°C for split seconds in the very surface (some microns).
Of course the block did not melt since the volume fraction of induced heat was to tiny to affect such a large solid piece of steel.
But the effect was there and proofen.
In a edge we just talk about some microns of material, here the effect is solid an clear.
Every manufacturer of razorblades knows this and does excessive cooling whilst grinding and polishing edges, that need to hold an super sharp edge for very long.
It seems just some the magic makers out of the custom knife scene think, the physical principles like this, do not apply to them....

 

[HeavyHanded]

When I heard about this experiment the first time I had to wonder what sort of controls were in place to isolate the temperature reading to actual parts of the block, as opposed to material that had been removed and was grinding across the thermocouple. While not the greatest conductor of heat, it conducts it pretty darn well. I have a difficult time believing that a point could reach such high temps with all that heat conducting mass around it. Clearly there is a need to add coolant when using powered wheels or platters loaded with abrasive, I have a tough time taking the results of this test at face value - as you mention, if true drawing a knife through cardboard would absolutely destroy the temper.

Then again, my own advice - keep an open mind. I've been proven wrong in my assumptions many , many times.

 

[Rick Marchand]

At the very edge, where exactly is all that heat conducting mass? The heat has to be there for it to be conducted away and it is in that short time that the damage is done. Those last few microns are out on a limb, so to speak. Without coolant, where does the heat go? Roman referenced sources that scrolled 3 pages all pointing to the same results. How does it translate to the everyday user? Not sure but when i see micrographs being posted by sharpeners SERIOUS about their edges... it has to come into play.

One thing I have noticed since using coolant, is that the burr is all but eliminated. Rather than plastically deforming, it is breaking off with little build up. I attribute this to the preserved hardness at the edge.

 

[Jason B.]

At the very edge, where exactly is all that heat conducting mass? The heat has to be there for it to be conducted away and it is in that short time that the damage is done. Those last few microns are out on a limb, so to speak. Without coolant, where does the heat go? Roman referenced sources that scrolled 3 pages all pointing to the same results. How does it translate to the everyday user? Not sure but when i see micrographs being posted by sharpeners SERIOUS about their edges... it has to come into play.

One thing I have noticed since using coolant, is that the burr is all but eliminated. Rather than plastically deforming, it is breaking off with little build up. I attribute this to the preserved hardness at the edge.

I must agree, sense I started using waterstones I have found my need to strop becoming less and less and often when I work on Japanese cutlery there is no need at all.

 

[HeavyHanded]

At the very edge, where exactly is all that heat conducting mass? The heat has to be there for it to be conducted away and it is in that short time that the damage is done. Those last few microns are out on a limb, so to speak. Without coolant, where does the heat go? Roman referenced sources that scrolled 3 pages all pointing to the same results. How does it translate to the everyday user? Not sure but when i see micrographs being posted by sharpeners SERIOUS about their edges... it has to come into play.

One thing I have noticed since using coolant, is that the burr is all but eliminated. Rather than plastically deforming, it is breaking off with little build up. I attribute this to the preserved hardness at the edge.

Interesting observation re burr formation, not sure if I've noticed this overall, but waterstones create such a small burr to begin with - I attribute this to the ability of any 'proud' abrasive bits to come loose instead of gouging the steel. Additionally, the abrasives that are already loose will attack any burr formation - this (to me) explains why edge trailing produces such a nice effect but edge leading does not (with waterstones). With fixed abrasive whetstones, I find the opposite to be true - in fact its extremely difficult in my experience to eliminate a burr using an edge trailing stroke on a fixed abrasive, with water, oil or dry.

I cannot speak to the heat generated at the edge - you have a very good point. Yet, the test item was a block of steel, not a blade. Without understanding how the thermocouples were isolated I remain skeptical - but will continue to use oil or water on any stone I'm sharpening with regardless...

When it comes to stropping I'm a lot more flexible.

 

[Jason B.]

Yeah, but that's BF, Rick. You've got a sharpening video that helped me a lot with my technique, and I know what kind of knives you are capable of making, so you'll always get full respect and consideration from me.

On the subject of stropping, I was looking at the kangaroo leather strops with glass backing. Those look very nice, but they're probably for people who can seriously refine an edge on the stones. With my final edges, I'd probably be wasting my time on plain kangaroo leather. But I think I'm gonna try the newspaper. Question for you: strop on dry or wet newspaper?

With the stones you are using it will be much easier than you think to produce a burr free or very close edge. The Roo leather is some of the best I have used and highly recommend it, you will find it to complement the edge a waterstone creates instead of destroys it as a abrasive compound can do.

 

[Rick Marchand]

Yet, the test item was a block of steel, not a blade. Without understanding how the thermocouples were isolated I remain skeptical

Agreed. I am not fully wraping my head around the intricacies of the experiment, either. I probably have a bias and lean toward most of what Roman Landes has to say about the science of knifemaking. He is one of the most active scientists(in the knifmaking community) I have ever corresponded with. (I don't mean active on the forums).

Here is one of the first threads I saw of his on BF (lots of broken links).

 

[BluntCut MetalWorks]

At the very edge, where exactly is all that heat conducting mass? The heat has to be there for it to be conducted away and it is in that short time that the damage is done. Those last few microns are out on a limb, so to speak. Without coolant, where does the heat go? Roman referenced sources that scrolled 3 pages all pointing to the same results. How does it translate to the everyday user? Not sure but when i see micrographs being posted by sharpeners SERIOUS about their edges... it has to come into play..

2 months ago, I wondered-out-loud about paper wheel somehow flash quench & heat treated the edge of soft steel knives
http://www.bladeforums.com/forums/showthread.php/964904-Paper-wheels-edge-heat-treatment?highlight=paper+wheel+heat+treatment
I caved-in ('tabled-it' in my brain) after Hardheart's convincing arguments.

For me, facts still - for many low hrc knives paper wheel get them screaming sharp. While using EP or waterstone or DMT/ceramic stone, I can't get them very sharp.

 

[HeavyHanded]

Agreed. I am not fully wraping my head around the intricacies of the experiment, either. I probably have a bias and lean toward most of what Roman Landes has to say about the science of knifemaking. He is one of the most active scientists(in the knifmaking community) I have ever corresponded with. (I don't mean active on the forums).

Don't get me wrong, I'm not discounting anything, been wrong about a number of sharpening related assumptions and will be again. Where there's smoke there's usually fire or at least something hot enough to burn ya.

Another thought re burr formation and stone types. In my quest to find other methods that mimic waterstones, I've tried all manner of stropping and grinding. The one that comes the closest without needing a bucket of water, is to make a thin slurry with some 600 grit SiC powder and oil on the fine side of a combination SIC stone. Makes for a very burr-free edge that must be finished with edge trailing motion to really be sharp, tho it still doesn't quite develop as nice as a true waterstone edge. Also winds up being even less convenient than waterstones for traveling and requires a supply of SiC powder - not an improvement in any respect, doesn't even work as well as the plain stone...but then the longer you work an oil stone the more of a slurry you're going to have anyway.

 

[BluntCut MetalWorks]

..
Roman Landes ran experiments with micro thermocouples inbedded in the very edge of blades being sharpened. Lightly dragging a blade along a dry stone generated temperatures in excess of 2000F. Loaded strops weren't much different. It was super-tempering the last few microns of steel at the edge... probably not noticeable in a woods chopper. I have to admit that his experiments had me wondering about what happens to the temper during a regular cut in wood, paper, etc... that has got to be generating heat as well?

Found it... Turns out it wasn't Roman's experiment but one he found in text...

THANKS for great info about grinding heat(GH) on edge, Rick! :thumbup:

If GH is below the tempered temperature then no further discussion. On other hand...

In light of new exciting data(new to me) and assumming GH exceed the tempered temperature. Perhaps it's a underlying reason for burr forming because the steel at the edge increase its ductility + toughness, consequentially more plastic flows and bend rather than detach. Maybe GH forced the working knowledge of using coolant & light pressure to prevent burr/wire and not ruin edge retention.

Thermal/heat vector for edge trailing grind is toward and partial-accummulation at edge. While manual cut/chop/edge-lead-activity thermal vector is from edge to spine(the blade serves as the heatsink) + minimal abrading, therefore not enough heat to de-temper the edge.