The Opinel: How Low can You Go?

B

BK14

Joined
Sep 13, 2016
Messages
449
My number 8 is at 15 DPS right now... but this is not an EDC blade, just what I use when I really want slicey. How low of an angle can you take an Opinel (carbon) before it becomes unstable for wood and cardboard?
 
I thinned my 'Carbone' No. 08 down to something well below 25° inclusive (12.5° per side); and it may even be at/around 20° inclusive. It's VERY thin at the edge, and I've noticed, kind of fragile too for anything putting lateral stress on the edge. Also vulnerable to edge impacts against anything hard, when this thin. If I were picking a lower limit for it in general, I'd likely not go below 25° inclusive (12.5° per side). The steel is relatively soft in the 'Carbone' version; I think the INOX Opinel would likely hold up better at similar geometry. I thinned one of those to similar geometry, in more-or-less a parallel experiment with the two knives, and the INOX (12C27Mod) seems more durable.


David
 
Obsessed with Edges said:
I thinned my 'Carbone' No. 08 down to something well below 25° inclusive (12.5° per side); and it may even be at/around 20° inclusive. It's VERY thin at the edge, and I've noticed, kind of fragile too for anything putting lateral stress on the edge. Also vulnerable to edge impacts against anything hard, when this thin. If I were picking a lower limit for it in general, I'd likely not go below 25° inclusive (12.5° per side). The steel is relatively soft in the 'Carbone' version; I think the INOX Opinel would likely hold up better at similar geometry. I thinned one of those to similar geometry, in more-or-less a parallel experiment with the two knives, and the INOX (12C27Mod) seems more durable.


David
Click to expand...
Good to know, thanks David. I may keep it at 15 for awhile.
 
The Inox is harder than the carbon? I would have guessed the opposite! Is that because they do different heat treats on the two versions? I though carbon steels were usually tougher than normal stainless (excluding modern super steels). Is it possible to generalize in this way?
 
  • Like
Reactions: vba
A fun and inexpensive knife for these experiments is the victorinox paring knives. Years ago, I learned a lot about basic sharpening with victorinox kitchen knives. I have some thinned out for soft veggie use that are little zingers
For prep .

Russ
 
Erik Norseman said:
The Inox is harder than the carbon? I would have guessed the opposite! Is that because they do different heat treats on the two versions? I though carbon steels were usually tougher than normal stainless (excluding modern super steels). Is it possible to generalize in this way?
Click to expand...
When it comes to simpler steels of older days, stainless blades were harder, and while they held an edge better, they were harder to sharpen and more prone to breaking. With modern steels its impossible to generalize as you can pretty much find a steel to do whatever you need.
As a broad generalization toughness and hardness are a trade off.
 
Erik Norseman said:
The Inox is harder than the carbon? I would have guessed the opposite! Is that because they do different heat treats on the two versions? I though carbon steels were usually tougher than normal stainless (excluding modern super steels). Is it possible to generalize in this way?
Click to expand...

This is just based on how I've seen each of my Opinels hold up, after thinning both of them to similar geometry. Modern stainless steels are often capable of as-good or sometimes better performance than the old-school, simpler carbon steel blades. A lot of that can be attributed to particular heat treat, or manufacturing purity (Sandvik's steels are known for this), or any combination of the two.

I suspect Opinel may've just been a little more conservative with the heat treat on their older 'Carbone' steel (XC90) recipe. The steel should be capable of good or better edge-holding, IF it was heat-treated to higher hardness. I just don't don't think they've done that yet, as compared to their INOX blades in Sandvik 12C27Mod, which is rated up to HRC 59 by Sandvik. A lot of other Opinel fans here have noticed this as well.


David
 
Last edited:
Erik Norseman said:
I see. Interesting.
I didn't know Opinel used Sandvik steel in their Inox blades. Cool!
Click to expand...

They've used the Sandvik 12C27Mod since 2002, according to an email reply from them, when I asked a while back. I have an older Opinel fillet knife, purchased in the early-mid 1980s, IIRC; it has behaved completely differently from newer stainless Opinels, in terms of how it sharpens up. I haven't liked it much, in that regard. That's why I asked Opinel to confirm if the newer INOX knives were different than the older ones. They are, and it was a huge improvement. :)
 
Last edited:
Frost/Mora also uses 12c27 in their fillet knives, they say at RC58. The newer models with the PG handles are "grippy" and razor knives. The thin 6, 7, or 8.25" models are very quick and easy to re-sharpen, not too much flex. Very nice production fillet knives for the money. Do mine at 30 inclusive.
 
Last edited:
gadgetgeek said:
When it comes to simpler steels of older days, stainless blades were harder, and while they held an edge better, they were harder to sharpen and more prone to breaking. With modern steels its impossible to generalize as you can pretty much find a steel to do whatever you need.
As a broad generalization toughness and hardness are a trade off.
Click to expand...

Actually, it was the reverse to start with. Stainless steel in general was developed in the 1920's and even by the 1940's it hadn't become commonplace. The stainless steels of those days were soft which is why we have the lore today of carbon steels taking and holding a better edge than stainless. Queen was the first company I'm aware of to use stainless steel successfully in commercially sold knives, but Buck was one of the first to bring a hard stainless blade to the market, and they're where the problems with sharpening and durability started popping up. Their old 440C blades were really quite glassy.
 
FortyTwoBlades said:
Actually, it was the reverse to start with. Stainless steel in general was developed in the 1920's and even by the 1940's it hadn't become commonplace. The stainless steels of those days were soft which is why we have the lore today of carbon steels taking and holding a better edge than stainless. Queen was the first company I'm aware of to use stainless steel successfully in commercially sold knives, but Buck was one of the first to bring a hard stainless blade to the market, and they're where the problems with sharpening and durability started popping up. Their old 440C blades were really quite glassy.
Click to expand...
Happy to be wrong when corrected by you 42! thanks for clearing that up.
 
Granted, I'm not infallible! But that's the timeline to the best of my recollection off the top of my head. :D
 
The carbon steel is tun prettybsoft. It will roll or fold at low angles. I've never measured mine, as I free hand, and also convex.

Their stainless seems to be run a little harder. Holds an edge longer, and can go a bit shallower on the angle.
 
Bigfattyt said:
The carbon steel is tun prettybsoft. It will roll or fold at low angles. I've never measured mine, as I free hand, and also convex.

Their stainless seems to be run a little harder. Holds an edge longer, and can go a bit shallower on the angle.
Click to expand...
Hi,
Opinel website says they aim for 57-59HRC ...
So,
Any guess as to what is "low angles"?
Cutting what when it rolls?
Equipment used to sharpen?
 
I bet you could take it down to 10° or so. Just careful of putting any significant side loads on it.
 
FortyTwoBlades said:
I bet you could take it down to 10° or so. Just careful of putting any significant side loads on it.
Click to expand...

This is probably where mine are, very near (or at) 10° per side. Great slicing in light work, such as kitchen use for fruits/veggies, etc. When they're fully tweaked out at the edge, it's fun to drop or toss grapes against the edge and split them. But my 'Carbone' Opinel is very vulnerable to impacts into the apex by anything very hard or tough, such as very dirty cardboard, wood, etc. A light bump against something like a staple in paper or cardboard leaves an obvious dent/roll in the edge. Similar light impacts against my INOX version haven't left the same sort of visibly obvious damage, at the same or very nearly the same geometry.

As of yesterday, I touched up the edge on the 'Carbone' with a quick microbevel, using a V-crock sharpener at 30° inclusive. I'm going to see how that makes a difference in that blade's ability to withstand some (slightly) heavier use. I'm leaving my INOX Opi as is, somewhere near that 10°/side mark, as it's been holding up pretty well in light to moderate use.
 
bucketstove said:
Hi,
Opinel website says they aim for 57-59HRC ...
So,
Any guess as to what is "low angles"?
Cutting what when it rolls?
Equipment used to sharpen?
Click to expand...

I've used a mix. Sand paper on a hard rubber backing. I've also used a belt sander, and diamond stone, silicone carbide, and ceramic sticks, often finished by stropping.

I'm not running my edges too thin on them.

I'd be shocked if any of my carbon opinel blades measured in the 57 to 59 rc. They seem softer, both when sharpening and using. The inox does seem there.

Still great whittler, and slicer, and worth the price, for sure.
 
Last edited:
You must log in or register to reply here.
Back
Top