Whetstone vs Tormek

[Sharpco]

Tormek can sharpen the knife quickly and precisely. But there are people who like whetstone more than Tormek, and some claim that blades sharpened with whetstone will last longer. So some of them first use Tormek and then finish with the whetstone.

Do you think whetstone's sharpening quality(edge retention etc.) is better than Tormek?

[grepper]

Mr. Sharpco,

Great question!

What are the factors in edge retention?

Hardness of the steel of the blade.
Brittleness of the steel.
Type of edge finish, toothy or polished.
Bevel angle.
Material the blade is cutting.
The amount of impact the edge suffers during use.
Initial sharpness.  A sharper edge is thinner.
Incomplete burr removal.

Consider what an abrasive does.  The abrasive removes steel to sharpen, (make thin) the edge.  Abrasive can be coarse or fine which will affect edge finish and how quickly steel is removed.  That's all an abrasive does.  Abrasives do not, and cannot, impart any magic quality, extra hardness or edge retention to the edge. 

IMHO, other than the above mentioned considerations, whether the abrasive is a Tormek wheel, an abrasive belt, a wet or dry stone or whatever, the type or brand of abrasive has nothing to do with edge retention. 

For whatever reason, (actually marketing), knife sharpening has been made way more mysterious than it actually is, and has created a marketplace that promotes over-thinking what is actually happening.  I see it all the time.  This stone is better than that stone.  You must use our brand of special sauce when honing.  Antelope butt leather is the only way to go for the "keenest" edge.  You can only get a "scary sharp" edge with paper wheels and diamond paste and on and on.  It makes something very simple seem almost impossible to understand when it does not need to be at all.  The marketing turns simplicity into a confusing, frustrating, hair pulling freak show that only some sort of Zen monk can understand and then only after years of tortuous study with copious blood and treasure spent. 

Please understand that I am by no means and expert, and really don't mean to come off as some sort of know-it-all... Really!  There is no perfect way to sharpen a knife, and everyone will develop their own methods of doing so.  That's the fun thing about sharpening; the learning and experimenting never ends. 

Anyway, I hope you find something useful in my diatribe. 

[Sharpco]

Mr. Sharpco,

Great question!

What are the factors in edge retention?

Hardness of the steel of the blade.
Brittleness of the steel.
Type of edge finish, toothy or polished.
Bevel angle.
Material the blade is cutting.
The amount of impact the edge suffers during use.
Initial sharpness.  A sharper edge is thinner.
Incomplete burr removal.

Consider what an abrasive does.  The abrasive removes steel to sharpen, (make thin) the edge.  Abrasive can be coarse or fine which will affect edge finish and how quickly steel is removed.  That's all an abrasive does.  Abrasives do not, and cannot, impart any magic quality, extra hardness or edge retention to the edge. 

IMHO, other than the above mentioned considerations, whether the abrasive is a Tormek wheel, an abrasive belt, a wet or dry stone or whatever, the type or brand of abrasive has nothing to do with edge retention. 

For whatever reason, (actually marketing), knife sharpening has been made way more mysterious than it actually is, and has created a marketplace that promotes over-thinking what is actually happening.  I see it all the time.  This stone is better than that stone.  You must use our brand of special sauce when honing.  Antelope butt leather is the only way to go for the "keenest" edge.  You can only get a "scary sharp" edge with paper wheels and diamond paste and on and on.  It makes something very simple seem almost impossible to understand when it does not need to be at all.  The marketing turns simplicity into a confusing, frustrating, hair pulling freak show that only some sort of Zen monk can understand and then only after years of tortuous study with copious blood and treasure spent. 

Please understand that I am by no means and expert, and really don't mean to come off as some sort of know-it-all... Really!  There is no perfect way to sharpen a knife, and everyone will develop their own methods of doing so.  That's the fun thing about sharpening; the learning and experimenting never ends. 

Anyway, I hope you find something useful in my diatribe. 

Thank you grepper.

I agree with your opinion. But there are people who make such claims, and many people who sharpen a very expensive kitchen knife use whetstone, so I wanted to hear your thoughts.

[Ken S]

Sharpco,

This is a very good question. I agree with Grepper's thoughtful answer. I used Norton waterstones for many years, and oilstones for many more years. Today, if it was not convenient to use my Tormek, I would use whetstones and be quite content with the result.

I might introduce one more factor. I can appreciate both preferences. I appreciate even more when the sharpener has mastered both the leather honing wheel and whetstones. When a whetstone preference is because of lack of skill with the leather honing wheel, I am not not so impressed.

I probably sound like the crusty old shop teacher who wanted his students to be able to plane a board square. Quite honestly, my preference is both.

I would add one other thought. I like to analyse why people prefer particular techniques. I think the preference for whetstones over grinders goes back to the heat generated by high speed dry grinders. In fairness, that problem is to some extent caused by poor technique. I think another factor is tradition, especially Japanese tradition. The samurai sword makers did not have to sharpen a hundred swords on a Saturday morning.

Family duty calls.  Good topic!

Ken

[cbwx34]

Tormek can sharpen the knife quickly and precisely. But there are people who like whetstone more than Tormek, and some claim that blades sharpened with whetstone will last longer. So some of them first use Tormek and then finish with the whetstone.

Do you think whetstone's sharpening quality(edge retention etc.) is better than Tormek?

This is one of those questions that to me, needs more information.  For example, I've found that some sharpeners will thin or reprofile on the Tormek, but use a "whetstone" to finish the edge, and add a small microbevel, which will aid in edge retention, and make subsequent touchups easier (which also makes the edge "last" longer).  This can be done on the Tormek, but might be easier just to make a "quick finish" on a stone, without having to make jig adjustments, etc.

Another factor might be using a stone that provides a different finish than the Tormek.  I also think it's often better to debur on a hard medium vs. leather, which can aid in edge retention.

Another thing you can do on a stone, that you really can't do on the Tormek, is alter the direction of the "teeth".  For example, if you point the teeth toward the heel, you'll get a better slicing edge, that can last longer.

So, my answer would be, yes, it's possible... it all depends.   

But, as I've stated before, "sharp" is a relative term.  So, while it may be possible to get a "better" edge off a whetstone... it doesn't mean that the Tormek edge is bad or not sharp... and is certainly better than a lot of options available.

[Jan]

I agree with your opinion. But there are people who make such claims, and many people who sharpen a very expensive kitchen knife use whetstone, so I wanted to hear your thoughts.

In my opinion some people require whetstone sharpening because it is the recommendation of the knife manufacturer (e.g. Global Knives). Waterstones sharpening with guide rails makes it possible to get quite consistent bevel angle for amateur knife grinders also.

The other reason for requiring the usage of waterstones by some people may be subconscious fear that any vertical wheel grinder, wet or dry, gives slightly hollow shape, which could weaken the edge.

We, Tormekers, know that this fear is not justified, but it is not so easy to convince the customer about it. See the lengthy discussion https://forum.tormek.com/index.php?topic=2413.0

Jan

[Ken S]

CB and Jan,

Good comments. Old myths die hard. I first learned about hollow grinding forty five years ago. In the days of six inch grinders, often with worn wheels, the hollow was quite noticeable. At the time, it was a very practical method. The hollow allowed the sharpener to rest the tool on two points. This created a natural micro bevel.

With the  Tormek 250mm grinding wheel,  and even with the 200mm wheels, the grinding is almost flat. Yes, almost is a key word, however, I have trouble seeing the hollow in a chisel, let alone the small bevel on a knife.

While I can appreciate those who create a secondary bevel with a bench stone, removing a tool from a Tormek jig and transferring it to another jig does not seem a time saver to me. Using the microadjust on the support bar is quick and repeatable. Whether one decides to raise the bar a turn or a turn and a half, the change will be consistent. I do not think this change is necessary, but that's just my opinion.

I don't have an informed opinion about harder material vs. leather for final honing.

As to the direction of the teeth, this sounds fascinating. It could be part of a really superior sharpening service. This would seem too time consuming for the farmers market circuit and probably more costly for the average customer who brings half a dozen inexpensive knives. It certainly seems a good technique to know and offer. While a more sophisticated customer might request this service, I believe most would decline if it involved extra cost.

Again, this is a worthy topic, and one which I hope will generate more thoughts.

Ken

[cbwx34]

In my opinion some people require whetstone sharpening because it is the recommendation of the knife manufacturer (e.g. Global Knives). Waterstones sharpening with guide rails makes it possible to get quite consistent bevel angle for amateur knife grinders also.

The other reason for requiring the usage of waterstones by some people may be subconscious fear that any vertical wheel grinder, wet or dry, gives slightly hollow shape, which could weaken the edge.

We, Tormekers, know that this fear is not justified, but it is not so easy to convince the customer about it. See the lengthy discussion https://forum.tormek.com/index.php?topic=2413.0

Jan

Great thread!  (Had to read it twice, but makes perfect sense). 

Sort of the reverse similarities of the misconceptions between convex and flat grinds.
(Don't make me sorry I said this.....). 

Edit to add:  Actually the arguments are more similar than reverse, since often convex and flat grinds are compared with the same wrong reference points, (for example, keeping the bevel width the same to prove a point).

[cbwx34]

CB and Jan,

Good comments. Old myths die hard. I first learned about hollow grinding forty five years ago. In the days of six inch grinders, often with worn wheels, the hollow was quite noticeable. At the time, it was a very practical method. The hollow allowed the sharpener to rest the tool on two points. This created a natural micro bevel.

With the  Tormek 250mm grinding wheel,  and even with the 200mm wheels, the grinding is almost flat. Yes, almost is a key word, however, I have trouble seeing the hollow in a chisel, let alone the small bevel on a knife.

While I can appreciate those who create a secondary bevel with a bench stone, removing a tool from a Tormek jig and transferring it to another jig does not seem a time saver to me. Using the microadjust on the support bar is quick and repeatable. Whether one decides to raise the bar a turn or a turn and a half, the change will be consistent. I do not think this change is necessary, but that's just my opinion.

I don't have an informed opinion about harder material vs. leather for final honing.

As to the direction of the teeth, this sounds fascinating. It could be part of a really superior sharpening service. This would seem too time consuming for the farmers market circuit and probably more costly for the average customer who brings half a dozen inexpensive knives. It certainly seems a good technique to know and offer. While a more sophisticated customer might request this service, I believe most would decline if it involved extra cost.

Again, this is a worthy topic, and one which I hope will generate more thoughts.

Ken

Usually "those who create a secondary bevel with a bench stone,...", don't use another jig to do it.  They'll freehand it, since it takes very little to do so.  Becomes more of a deburr/add microbevel technique, all-in-one, if that makes sense.

Think leather wheel vs. SJ stone, for one example of the difference in 'hard vs. soft' edge finishing.  Finishing on softer material can often result in as sharp or sharper edge, but with the loss of "bite" more noticeable.

"Direction of the teeth" isn't that hard to do, and no more time consuming.  But it does depend on what's being used to sharpen, and unfortunately, the Tormek isn't really the platform for it.  But, just like the debur and/or add microbevel, it can be done on a flat stone, in most cases with relatively ease.  But it's usually done on a knife that is "task specific"... most users won't benefit if they use their knives for a variety of cutting techniques.

[Jan]

When I thought a little bit about the differences between waterstones and water-cooled sharpening this occurred to me. During sharpening on waterstones the water combines with grains released from the stone and forms a special abrasive substance – slurry swarf*.

This thin mud plays quite important role, because it allows for finer and less aggressive sharpening effect. The slurry swarf contains many blunted grains but also microscopic steel particles.

During sharpening on Tormek the slurry swarf is immediately washed out and new sharp grains are exposed on the stone circumference.

Jan

*P.S.:  CB was so kind and explained me the difference between slurry and swarf. Thanks!

[cbwx34]

When I thought a little bit about the differences between waterstones and water-cooled sharpening this occurred to me. During sharpening on waterstones the water combines with grains released from the stone and forms a special abrasive substance – slurry swarf*.

This thin mud plays quite important role, because it allows for finer and less aggressive sharpening effect. The slurry swarf contains many blunted grains but also microscopic steel particles.

During sharpening on Tormek the slurry swarf is immediately washed out and new sharp grains are exposed on the stone circumference.

Jan

*P.S.:  CB was so kind and explained me the difference between slurry and swarf. Thanks!

Slurry Swarf on the stone is a good point.

Edit:  I had to change mine... to match yours.    

p.s.  For those who care... slurry is generally considered the "mud" you create on a waterstone prior to sharpening (with a nagura stone for example)... swarf is the mixture of mud and the metal from the knife during sharpening.

[Ken S]

I generally subscribe to the Tormek philosophy that secondary bevels are not necessary with the Tormek. Secondary or micro bevels are a labor saving short cut for manual sharpening. They work well with dry grinding be shifting the final sharpening to the bench stone, thus keeping the hot dry grindstone away from the thinnest part of the blade. With the Tormek, there is no danger of overheating. the motor of the Tormek does the heavy labor. There is no nee for a micro bevel.

Ken

[cbwx34]

I generally subscribe to the Tormek philosophy that secondary bevels are not necessary with the Tormek. Secondary or micro bevels are a labor saving short cut for manual sharpening. They work well with dry grinding be shifting the final sharpening to the bench stone, thus keeping the hot dry grindstone away from the thinnest part of the blade. With the Tormek, there is no danger of overheating. the motor of the Tormek does the heavy labor. There is no nee for a micro bevel.

Ken

Gotta be honest... I don't think whether or not a microbevel should be used...  really has anything to do with the Tormek.  They allow the sharpener to... create a sharp edge faster, make a more durable edge when needed, great - quick & easy way to debur, ease of maintenance during use, etc.  My .02.   

[Jan]

I generally subscribe to the Tormek philosophy that secondary bevels are not necessary with the Tormek. Secondary or micro bevels are a labor saving short cut for manual sharpening. They work well with dry grinding be shifting the final sharpening to the bench stone, thus keeping the hot dry grindstone away from the thinnest part of the blade. With the Tormek, there is no danger of overheating. the motor of the Tormek does the heavy labor. There is no nee for a micro bevel.

Ken

Ken, you are correct what concerns Tormek philosophy for secondary bevels on wood chisels and plane irons!

In my understanding the situation with knife edges is somewhat different. Recently I have carefully studied one new Swedish outdoor knife with scandi grind. The included angle of the scandi (primary) grind was 22° while the microbevel angle was 36°. The length of the scandi grind was 6 mm while the length of the microbevel was only 0.1 mm.

If the edge needs only minor maintenance, it may be sufficient to sharpen/hone the microbevel only. When the edge is worn and blunt we have to grind the primary bevel first and restore the 22° angle and then sharpen the microbevel with an angle of 36°.

The microbevel makes the edge stronger, less vulnerable and guarantees better edge retention.

Jan

[Ken S]

Jan,

You make a very good point. As most of you know, I am really a chisel person. I became more of a knife person when I met Steve Bottorff. Steve has become a friend as well as a mentor. I spend as much time now with knives as with woodworking tools. My advice to the forum would be never pass up an opportunity to learn from a master. Such an opportunity is a rare gift.

Ken