What is a micro bevel on a scandi grind?

N

neeman

Joined
Apr 5, 2007
Messages
6,249
Hi Guys,
I am posting this question here because I see you as the main users of scandi grinds
I need your combined advice


The story:
I have received a 4" custom Woodlore clone in 01
My first custom
Lovely knife
No names.....and the maker will remain private

The grind from the website is a scandi with a “secondary micro convex bevel”
What is reasonable to expect this to be.
I am going to defer to your greater knowledge in making up my mind what to do

I wrote
"The “secondary micro convex bevel” is actually a full blown secondary bevel.
The cutting edge is now the secondary bevel and the Scandi is rendered as cosmetic, where the edge could be a saber grind.
The secondary grind has cut into the Scandi edge deep enough to have the cutting edge be a much more obtuse angle
So to cut I need to pick the blade up and use the secondary edge and the Scandi geometry of the blade is not used"


The secondary edge is a measureble 1/32"
Without grinding back to close to the scandi grind, I will never have a scandi grind, at each sharpening I will always be deepening the secondary bevel

Your advice please

thank you
 
I propose that a true scandi bevel only lasts until the first sharpening. I doubt if anyone that sharpens a scandi removes material for the full height of the bevel which is what you would have to do to maintain it as a pure scandi. Anything less and you are creating some form of micro bevel.

I don't think this is an issue though, just sharpen it at the steepest angle that you can use and actually make progress with sharpening. The farther that the blade wears the steeper this angle will end up being. If it gets too bad then you will need to somewhat reprofile the blade and then you start over with it.

Lets say you like a 40 degree inclusive as your steepest grind. With a scandi bevel of a 1/8" thick blade the bevel would only be about 3/16" tall so most scandi knives have less angle. Having a microbevel at a steeper angle should not be a problem because you could do a lot of sharpening on it before you get to a full 40 degree inclusive.
 
neeman said:
The secondary grind has cut into the Scandi edge deep enough to have the cutting edge be a much more obtuse angle
So to cut I need to pick the blade up and use the secondary edge and the Scandi geometry of the blade is not used"


The secondary edge is a measureble 1/32"
Without grinding back to close to the scandi grind, I will never have a scandi grind, at each sharpening I will always be deepening the secondary bevel

Your advice please

thank you
Click to expand...

IMHO you should, when sharpening, try to expand the Scandi edge as you go and just touch on the convex "secondary" edge. In the process you'll learn how to sharpen a convex edge on a hard stone. You are correct in thinking that you'll have a very obtuse bevel if you don't limit the microbevel with each sharpening. An inclusive angle of 25-30 degrees should still leave you with a very resilient Scandi edge. I have successfully recovered a number of Scandi grinds that came to me with a secondary microbevel, but you might as well use them as you go or that's a lot of steel ground away with no benefit. It will cut better with each grinding. As long as you don't go so steep that you cannot finish the edge off without making it too weak, you're doing fine. Just beat on the Scandi edge first when sharpening, and gently raise the spine to lightly hit the microbevel. As you clear out the steel behind the micobevel it will be more and more of a true Scandi (which in my experience still involves a bit of convex, but not more than a few degrees from secondary bevel to the apex). All Scandis should have the primary edge thinned with every sharpening - in truth every blade profile should have the back bevel thinned frequently when sharpening a fresh apex but this is often ignored.

Nice get, enjoy the knife!
 
bdmicarta said:
I propose that a true scandi bevel only lasts until the first sharpening. I doubt if anyone that sharpens a scandi removes material for the full height of the bevel which is what you would have to do to maintain it as a pure scandi.
Click to expand...

Hey bdmicarta,

I think it is very common to sharpen the full height of the grind on a scandi. Actually, it is the reason for one of the great benefits of sharpening scandi knives - you won't have a problem with the sharpening angle on wetstones.

Best regards,

ll
 
I am far from a Scandi edge expert, but in my experience I was disappointed in performance and edge holding until I applied a micro bevel to them. Even on a relatively thick Scandi like my Spyderco Bushcraft, the edge would roll quite easily and feel dull very fast. A micro bevel improved edge retention dramatically.
 
This thread is just odd to me. I sharpen a Scandi like it should be sharpened (Zero ground - full flat sharpen) every time - and have used wet/dry sand paper over a flat plate of glass, Japanese water stones, and DMT plates - either way - it all works.

Here is how it is done:

http://youtu.be/Lm53mCOQTR8

If you are going to micro bevel a Scandi - simply get a flat ground blade with a double bevel - and be done with it. Scandi grinds exist the way they do - for a reason - they are not for every situation - but in my opinion - if you are rolling the edge, or putting in a double bevel - you have a problem with your knife (heat treat - or poor steel) or a problem with your technique (you don't know how to sharpen a scandi properly).

It took me a while to master - but now that I understand the mechanics - and the place for a scandi - it is a great knife.


TF
 
“What is a micro bevel on a scandi grind?” - It's the equivalent of putting tractor tyres on a Porsche that's what it is..................True enough traditional Scandinavian knives vary in their edge geometries and may have a micro bevel depending on whether it is for hunting, rough work, or working wood. To my mind though that's just what happens when a platform is used for everything rather than adopting new and perhaps more appropriate platforms when task dictate that's a good idea. As you've said yourself all you've got there is a stubby sabre grind with all the merits of what Scandis are supposed to excel at being so marginalized they don't even figure in the result................I think they are consumer trendy because they are all neo-bushcrafty but I think you've wasted your time. Personally, I think if you want a neo-bushcraft knife for rough work too make sure you get it in a material that will be stable at the required geometry under those punishing conditions not make it a big thick lump and violate the geometry. That said, if I wanted a knife that could take a bit of rough I wouldn't pick the Scandi platform to begin with................Rather than looking at what vendors / shills / fashion conscious theorists would have a person buy I think a better approach is to look at what Bodgers [green wood workers] and woodcarvers [like on woodcarving illustrated .com] actually use. The stuff that they produce is what Scandi knives are often sold for under the neo-bushcraft rubric. You'll soon notice that flat and thin is good, even hollow ground, but the convex that I and many other use for toughness is a diss, so too any other extra hinderance to cutting performance. This woman is a carver. I wonder what she'd make of the popular neo-bushcraft knives with extra bevels for working wood.
 
Not sure how a micro bevel could possibly take away from the performance in the slightest, but like I said, I'm no Scandi expert.
 
neeman said:
Hi Guys,
I am posting this question here because I see you as the main users of scandi grinds
I need your combined advice


The story:
I have received a 4" custom Woodlore clone in 01
My first custom
Lovely knife
No names.....and the maker will remain private

The grind from the website is a scandi with a “secondary micro convex bevel”
What is reasonable to expect this to be.
I am going to defer to your greater knowledge in making up my mind what to do

I wrote
"The “secondary micro convex bevel” is actually a full blown secondary bevel.
The cutting edge is now the secondary bevel and the Scandi is rendered as cosmetic, where the edge could be a saber grind.
The secondary grind has cut into the Scandi edge deep enough to have the cutting edge be a much more obtuse angle
So to cut I need to pick the blade up and use the secondary edge and the Scandi geometry of the blade is not used"


The secondary edge is a measureble 1/32"
Without grinding back to close to the scandi grind, I will never have a scandi grind, at each sharpening I will always be deepening the secondary bevel

Your advice please

thank you
Click to expand...




1/32"? That's a serious secondary bevel for a Scandi.


I suspect the maker is afraid of thinning the edge enough to make a true zero edge Scandi.

They can be quite fragile.


Calling 1/32" secondary bevels on a knife advertised as a Scandi grind to be a “secondary micro convex bevel” sounds misleading to me.


To me, a “secondary micro convex bevel” on a Scandi grind would be along the lines of stropping a zero edge Scandi to polish the edge.


JMHO, YMMV.




Big Mike
 
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Talfuchre said:
This thread is just odd to me. I sharpen a Scandi like it should be sharpened (Zero ground - full flat sharpen) every time - and have used wet/dry sand paper over a flat plate of glass, Japanese water stones, and DMT plates - either way - it all works.

Here is how it is done:

http://youtu.be/Lm53mCOQTR8

If you are going to micro bevel a Scandi - simply get a flat ground blade with a double bevel - and be done with it. Scandi grinds exist the way they do - for a reason - they are not for every situation - but in my opinion - if you are rolling the edge, or putting in a double bevel - you have a problem with your knife (heat treat - or poor steel) or a problem with your technique (you don't know how to sharpen a scandi properly).

It took me a while to master - but now that I understand the mechanics - and the place for a scandi - it is a great knife.


TF
Click to expand...

Here's the rub, Scandi grinds from different makers (and sometimes from the same maker) have different inclusive bevel angles. One Mora I had clocked in at 16-18 inclusive. That is way too acute for anything but shaving - I slightly convexed it and then with subsequent sharpenings slowly increased the inclusive angle to a much more robust 23 degrees (approximate) while flattening out the planes.

My Jarvenpaa came with an inclusive closer to 25-28 with a very small microbevel - I ground it to the Scandi backbevel and it holds up great. I don't like a microbevel on a Scandi, but there are combinations of steel type and inclusive bevel angle that just don't work well. Final thought, none of my Scandis came with a bevel as flat as I could get it on a stone, they all had a slight convex - no more than a degree or two deviation from shoulder to apex, but an arc nonetheless.
 
Big Mike said:
1/32"? That's a serious secondary bevel for a Scandi.


I suspect the maker is afraid of thinning the edge enough to make a true zero edge Scandi.

They can be quite fragile.


Calling 1/32" secondary bevels on a knife advertised as a Scandi grind to be a “secondary micro convex bevel” sounds misleading to me.


To me, a “secondary micro convex bevel” on a Scandi grind would be along the lines of stropping a zero edge Scandi to polish the edge.


JMHO, YMMV.




Big Mike
Click to expand...


This is how I feel about it also.
 
HeavyHanded said:
Here's the rub, Scandi grinds from different makers (and sometimes from the same maker) have different inclusive bevel angles. One Mora I had clocked in at 16-18 inclusive. That is way too acute for anything but shaving - I slightly convexed it and then with subsequent sharpenings slowly increased the inclusive angle to a much more robust 23 degrees (approximate) while flattening out the planes.

My Jarvenpaa came with an inclusive closer to 25-28 with a very small microbevel - I ground it to the Scandi backbevel and it holds up great. I don't like a microbevel on a Scandi, but there are combinations of steel type and inclusive bevel angle that just don't work well. Final thought, none of my Scandis came with a bevel as flat as I could get it on a stone, they all had a slight convex - no more than a degree or two deviation from shoulder to apex, but an arc nonetheless.
Click to expand...

Good point - I should have added - poor design or execution to list of what could be wrong if you NEED a secondary bevel on your scandi.

I also agree with Mike - I strop my Scandi's - I suppose we could call that a secondary bevel - but it is so micro as to not be an issue when I resharpen.

TF
 
These are just humble hobbyist thoughts
There is a relationship between the hardness of the steel and the hardness of the wood you can cut at a given scandigrind angle. If you step outside the boundaries of this relationship the edge wont last due to chipping or distortion. A quick fix is to ad a secondary bevel. This means that just bringing the knife back to zero grind "might" unveil why the bevel was put there in the first place.

I have a secondary bevel both on a knife that is to soft and one that is to hard. Both work great but needs a fancy jig (on a tormek grinder) for reshaping the edge between stropping periods.
 
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lightleak said:
If stropping is considered a secondary bevel - I apply one as well.

ll.
Click to expand...



Remember, what we are talking about here is what the maker refers to as a “secondary micro convex bevel” on a knife billed as a Scandi grind.

We are not talking about regular secondary bevels.


I think it's fair to call any bevel created by stropping a zero edge small enough a convex to be considered "micro".


In my opinion, the size of the bevels the OP mentions are large enough be beyond "micro" in size.




Big Mike
 
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A microbevel is a feature that makes a scandi grind usable in the real world. No really, when I had a scandi I put a small convex microbevel on mine and it worked just fine.
 
My m2k has been my primary fixed blade for the three or four years now. You'd think in that time I'd stop being so impressed by the edge retention, but I sharpen flat on a stone. I very rarely have to do that, I just strop on leather with green rouge until polished.

The minute convexing that results may be how it retains its effortless cutting edge after working through hard media, which I try to achieve on other knives (including some scandis), but can't.
 
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