How to sharpen scandinavian grinds with the Tormek.

[Sharpco]

Check the F.A.Q of MORA. They recommend Tormek.

Is this what you're referring to?

What equipment should I use for sharpening?
It all depends on what resources and equipment you've got at hand. For more advanced users a TORMEK grinder at home may be an option (they also have plenty of informative and educational videos available on YouTube). In the field more easily carried diamond sharpeners (medium/fine and extra fine) come in handy. For an extra last touch, finish with stroping the knife on the back side of a leather belt.

https://morakniv.se/en/faq/

Not exactly packed with info...  (why "advanced users"?  and no info on how...) 

Maybe the videos Tormek was going to make will be helpful... 

I did run across this short video clip of a Morakniv sharpened on a Tormek that looked promising... (unfortunately not any info on how it was done).

https://youtu.be/ZPPv4EKvjsQ

Yes. That's it.

[Marc]

Thanks again to all those who replied to this post making it quite rich and useful  .

The correct answer to my original question appears to be: it's up to the user whether he wants to sharpen a scandi grind on the Tormek or not.

Here is my personal position for now:

First note that even if I've owned a Tormek for eight months now (so I'm still a beginner), I've been into sharpening for seven years, so I think I can rely a bit on my experience.

For me a scandinavian ground knife should have a flat bevel and no secondary  bevel. It might have a micro-convex bevel obtained by stroping on leather for better edge retention.

In my experience, if you use your knife correctly, this flat grind is NOT too weak. The question here is who needs to adapt to the other, the tool or the user? I think that the user should know the limits of his tool and use it accordingly.

But it seems that not everybody shares my views. So there are people who want to use a scandinavian ground knife for everything and would complain if it does not perform well at some tasks (deboning multiple pieces of meat or cutting cardboard all day long for example). I suspect that a company like Morakniv tries to adapt to this behavior by releasing knives with micro bevels (as seen on the Bushcraft Black). In my opinion this operation removes or at least reduces the most important feature of a scandinavian knife. Therefore many users, including me, remove the secondary bevel on their Mora knives prior to using them. And yes the knife performs well without the micro bevel, because we use it wisely.

One last thing about this annoying micro bevel; I own a high end Finish Roselli carpenter knife and it came with no secondary bevel. It holds a very keen edge for a long time even when I whittle hard wood.

Now about sharpening a scandi grind with the Tormek, I would not do it despite what I saw in the video about the wood carvers who make horses in Sweden. If I'm in a hurry, I would do it, but not if I have the time to work properly. As far as I'm concerned the slight hollow grind that the wheel would do is not acceptable. You need also to consider that the smaller the grind wheel, the deeper the hollow grind would be.

Nothing like a good flat bench stone to sharpen these knives the proper way.

[Badneo]

So, for us total newbs, how would you sharpen a Mora knife on the Tormek then?

[Sharpco]

So, for us total newbs, how would you sharpen a Mora knife on the Tormek then?

I believe angle is important. So I think we don't have to grind entire bevel of scandi knives. I just set 12~13 dps and sharpen it.

[cbwx34]

So, for us total newbs, how would you sharpen a Mora knife on the Tormek then?

Based on Marc's earlier post...

Example of a Mora knife with a micro convex bevel: The Mora Companion.

Example of a Mora knife with a micro bevel: The Mora Bushcraft Black

...I would first say, it depends on the type of Mora... and whether or not it has a microbevel.

Then, I would say, it depends on whether or not you want to keep it a "true" scandi grind. 

I believe angle is important. So I think we don't have to grind entire bevel of scandi knives. I just set 12~13 dps and sharpen it.

I think most users would be satisfied with a small microbevel, sharpened as SHARPCO stated.

[Ken S]

I am curious to hear what Tormek will say with the new diamond wheels and Multi Base. We really need an in depth knife video.

Ken

[cbwx34]

Ran across this video that demo's a scandi ground knife being redone on the Tormek... thought might be of interest...

https://youtu.be/whRdc6sDv3E

...(as he says at the end, a "learning" video, not necessarily a "how-to", but does show some of the results of doing it on a Tormek).

[wanderingwhittler]

I've now used the Tormek to help sharpen a couple of scandi-ground knives and would like to contribute some thoughts to this thread.

I want to start by saying that, like Marc, I use my scandi-ground knives for woodcarving and any concavity in the edge—even that from a microbevel—is noticeable and adversely affects the carving performance [1]. Also like Marc, I've found that a flat zero grind works well for me for the non-woodworking tasks for which I use a scandi-ground knife like a puukko. I recognize that others have different use patterns and preferences and a microbevel or other style of grinding/sharpening may be more appropriate for them, but comparison with the flat zero grind is the context of this post.

The shallow hollow produced by the Tormek does not bother me. At least not when there are small flats added to it by honing the edge and shoulder of the bevel. I first came across the concept of a "flat over hollow" grind for slöjd knives in the context of green wood spoon carving. This style of sharpening begins with using a wheel to grind a hollow bevel and finishes with using flat stones to hone small flat areas at the apex and shoulder of the bevel. Resharpening is accomplished just with flat stones until the edge becomes convex, and then a new hollow is ground.

It appears that this is a time-honored way of sharpening scandi-ground knives for woodcarving, at least in Sweden. The late master Swedish carver, Wille Sundqvist, has an extensive chapter on sharpening in his book Swedish Carving Techniques and this flat over hollow style of sharpening is what he describes for both knives and axes [2]. He distinguishes the grinding step (done on a wet wheel) from the honing step (done on flat stones). On page 34, he says that "it's an advantage to grind knives on a large-diameter grindstone, such as 250mm to 600mm (18 in. to 24 in.)", but also says on page 35 that "[t]he Tormek grinder pictured below is a good one, in spite of the small 250mm (10-in.) stone". I'm not sure which model of Tormek is pictured, but it's an old one: the English translation of his book is Copyright 1990.

I like this way of looking at it, excerpted from page 40:

"The slight hollow grind you get on the bevel when using a large-diameter stone is no problem. In fact it probably serves as proof that the bevel is not convex. A slightly concave bevel can be honed many times without becoming convex."

This is how I've sharpened both a Mora 120 that I use for woodcarving and a Marttiini Lynx Lumberjack that I use a bit for carving, but mostly for general-purpose use around the house and in the garden. The Mora 120 works great. In side-by-side comparisons, its carving performance has been indistinguishable from that of another Mora 120 which has a true flat zero grind. For this use, I'm sold.

I haven't really put the Lynx Lumberjack through its paces yet with the new edge, but I'm very happy with how it has tackled slicing cheese and salami and breaking down a cardboard pizza box. Neither of those are my typical uses for the knife, but it was handy and I thought I'd give it a try. I also used it to trim some relatively hard, but not brittle, plastic pieces today and the edge seems no worse for wear. I'll need more long term experience with this knife before I'm ready to cast a final verdict, but so far I'm enjoying using it.

In summary, I'm quite happy with this approach of using the Tormek to relatively quickly establish the hollow and then using stones to relatively quickly hone small flats. I have another puukko knife that came with a microbevel and I'll be using this technique to remove it rather than going through the work of grinding it out with flat stones.

Note that it does take a bit of practice to get the grind right on such a large bevel, so I'd offer the usual advice of practicing on a knife that isn't precious to you. You don't have grind perfectly up to the apex, by the way, just close enough to be able to finish with flat stones.

Finally, with respect to its aesthetics, I personally like the contrast of the highly polished flats against the fine scratch pattern in the hollow left after a few passes at fine grading.



Edited to add sharpening notes:
- Mora 120—sharpened using SVM-45 + SVM-00. Required lifting only. Required adjusting the SVM-45 separately for each side.
- Marttiini Lynx Lumberjack—sharpened using the SVM-45. Required pivoting. Required adjusting the SVM-45 separately for each side

In both cases, the flats were added with DMT DiaSharp fine followed by ultrafine stones. They were then stropped on a pair of kangaroo leather strops, first suede with Tormek honing paste and then smooth without any compound.

Note that Sundqvist encourages learning to do it freehand in part because "...jigs are not universally available or applicable" and also to maintain the cultural heritage (page 39).   



[1] This is not to say I'm against a concave edge for carving in all circumstances. I actually like a bit of concave to the edge of my small whittling blades. It works well for carving small-scale convex shapes.
[2] He also describes sharpening gouges and adzes with a grinding step on a wheel and honing step on flat stones, but I do not know enough about these tools to know whether this results in a flat-over-hollow grind on their curved surfaces.

[Jan]

Greg, I have read your post with great interest because I have quite new Mora 120 carving knife which I have not sharpen yet. The blade of my knife is made of laminated carbon steel, the core hardness is 58 to 60 HRC. On the bevel you can see where the hard core begins.

In my understanding the new Multi Base MB100 and the side coated diamond wheel would allow to sharpen the flat Scandi grind directly on Tormek machine. Correct?

Jan

[wanderingwhittler]

Greg, I have read your post with great interest because I have quite new Mora 120 carving knife which I have not sharpen yet. The blade of my knife is made of laminated carbon steel, the core hardness is 58 to 60 HRC. On the bevel you can see where the hard core begins.

In my understanding the new Multi Base MB100 and the side coated diamond wheel would allow to sharpen the flat Scandi grind directly on Tormek machine. Correct?

Jan

Hi Jan,

The blades of my Mora 120s (and my 106) are the laminated ones you describe. I like them.

I have the same understanding as you about the MB100 and diamond wheels, but I have neither. I would be interested in hearing how it goes if you or anyone else tries it.

Greg

[cbwx34]

...
I like this way of looking at it, excerpted from page 40:

"The slight hollow grind you get on the bevel when using a large-diameter stone is no problem. In fact it probably serves as proof that the bevel is not convex. A slightly concave bevel can be honed many times without becoming convex."
...

A most interesting post... thanks for taking the time.  (You should make a video).   I found the above quote interesting... hadn't thought about it that way before.

[Marc]

Hi Greg, thanks for your precious contribution. I will be experimenting with the technique you describe. I agree with cbwx34 about the video. Some details are better seen in a video than in a detailed text description.

[GKC]

I might be complicating things here, but I think that, for the reasons Greg gives, Marc's objection to micro bevels on scandi grinds can be separated from the use of hollow grinding in the sharpening of scandi blades.

I use a number of scandi ground whittling knives, Moras and customs.  As with Greg, I don't distinguish whittling with a flat zero ground scandi and a hollow ground scandi that has had the edge and shoulder of the hollow flattened in the traditional way on a flat stone (the flats are sometimes called "tram lines"). 

Several prominent carvers, doubtless influenced by Sundqvist but accomplished in their own right, use this approach.  In fact, probably most do.  Note that this is not a "correction" of a scandi that has been hollow ground.  The hollow grind is a necessary part of the sharpening method: by using the hollow grind, you dramatically reduce the amount of metal that you have to remove to get two dead flat surfaces meeting at the apex. 

This method does produce an apex that might be called a micro bevel, but it is not the usual kind of micro bevel of the kind that annoys Marc (and that I too don't usually want on a carving blade): a less acute apex relative to the grind of the blade.  The apex of the micro bevel produced when putting tram lines over a hollow grind is at exactly the same angle as would have been produced by a fully flat zero grind, it is just that there is a microscopic bit of air behind the bevel before you reach the flat on the other side of the hollow.  The point of this particular type of micro bevel is not to produce a more robust edge (as Marc says, we don't need to hack at bones with our whittling knives), but to reduce the amount of metal that has to be removed to produce an identical edge to the fully flat grind.

I think that if Marc used this approach he would find that he can get the basic grind done on the Tormek and then do a very quick flattening on a flat stone to get the apex he wants.  The blade can be re-sharpened many times with a few passes on a flat stone before it needs to go back on the wheel.

When Tormek gets it diamond wheel supply shortage sorted out I will see what can be done with the sides of the diamond wheels and the MB-100, but that is just to see what I can do on the flat sides, I am not searching for a fully flat scandi grind that I have to repeat every time I want a sharp edge.

Gord

[cbwx34]

I might be complicating things here, but I think that, for the reasons Greg gives, Marc's objection to micro bevels on scandi grinds can be separated from the use of hollow grinding in the sharpening of scandi blades.

I use a number of scandi ground whittling knives, Moras and customs.  As with Greg, I don't distinguish whittling with a flat zero ground scandi and a hollow ground scandi that has had the edge and shoulder of the hollow flattened in the traditional way on a flat stone (the flats are sometimes called "tram lines"). 

Several prominent carvers, doubtless influenced by Sundqvist but accomplished in their own right, use this approach.  In fact, probably most do.  Note that this is not a "correction" of a scandi that has been hollow ground.  The hollow grind is a necessary part of the sharpening method: by using the hollow grind, you dramatically reduce the amount of metal that you have to remove to get two dead flat surfaces meeting at the apex. 

This method does produce an apex that might be called a micro bevel, but it is not the usual kind of micro bevel of the kind that annoys Marc (and that I too don't usually want on a carving blade): a less acute apex relative to the grind of the blade.  The apex of the micro bevel produced when putting tram lines over a hollow grind is at exactly the same angle as would have been produced by a fully flat zero grind, it is just that there is a microscopic bit of air behind the bevel before you reach the flat on the other side of the hollow.  The point of this particular type of micro bevel is not to produce a more robust edge (as Marc says, we don't need to hack at bones with our whittling knives), but to reduce the amount of metal that has to be removed to produce an identical edge to the fully flat grind.

I think that if Marc used this approach he would find that he can get the basic grind done on the Tormek and then do a very quick flattening on a flat stone to get the apex he wants.  The blade can be re-sharpened many times with a few passes on a flat stone before it needs to go back on the wheel.

When Tormek gets it diamond wheel supply shortage sorted out I will see what can be done with the sides of the diamond wheels and the MB-100, but that is just to see what I can do on the flat sides, I am not searching for a fully flat scandi grind that I have to repeat every time I want a sharp edge.

Gord

Good description... I think you simplified it.

I tried to sketch out the part in bold...



... ('cause I need to practice drawing).

[Marc]

Excellent!

GKC, far from complicating things you made then quite clear, and cbwx34's sketches made them crystal clear!

Now I think that everybody sees what it's all about, and even before trying I am convinced that one can proprely sharpen a scandinavian grind with a Tormek by usnig the "flat over hollow" method.

Thank you guys