Can I make a sodbuster cut as well as an opinel?

[TXoutback]

So I've been testing a lot with my knife collection and I've found they can all do most of my daily tasks well enough. I tested:

• Benchmade Mini-griptilian (clip point blade)
• Buck Vantage Avid
• Case Sodbuster Jr.
• Ontario Rat 2
• Opinel #7

But one test stood out as having a marked difference in performance... whittling a piece of dried mulberry ( hard like oak, but with finer wood grain ).

Of all the knifes, the Opinel shaved off pieces of the mulberry like it was soft pine, while the others all really struggled to bite it, except the Ontario. Both the Opinel and the Rat II have full flat grinds, and I felt like I could lay them down at a finer angle than the others.

Of all these, I prefer to carry and use the Sodbuster Jr. the most for doing rough work around my homestead. I just love the look, feel, and carry of the Soddy for chores.

I'd like to know if it would be possible to adjust the edge of the Soddie to carve like the Opinel. The Soddie is a little bit thicker, but not as thick as the Ontario. The biggest difference is that the Soddie has a hollow grind instead of a flat.

Any advice is appreciated.

 

[cbwx34]

The Soddie is a little bit thicker, but not as thick as the Ontario...

The answer, in part anyway, is probably right here. Geometry (thickness) behind the edge plays a big part in how an edge performs. So even "a little bit thicker", combined with the angle of the edge, is probably the difference in performance between the two.

So, (unless there's something specific about these two knives I'm not seeing... I don't have either one), if you can thin the profile a bit, and lower the sharpened angle, you should hit the performance you're aiming for.

 

[TXoutback]

Thanks. I have a belt sander, but I'm planning to try doing it on a stone instead. I guess I should make a wooden angle guide at about 20° to start with.

 

[lutejones]

The answer is right in your picture, the bevel on the sodbuster saw as a light ribbon on the edge is what makes the difference cutting wood. The angle of presentation of the cutting edge is a lot higher on the soddie compared to the Opinel which is practically a zero ° convex.
The wood is like a bundle of straws jointed together this is why even at the same sharpness(width of the apex) the Opinel is cutting them at a far more lower and favorable angle while the sodbuster is almost shaving across the grain (exaggeration).
My advice is: put the soddie flat on the belt sander and thin it down until it is around 0.010" aound 1/64" up from the edge and you'll get similar performance.
Knocking off the shoulders will help too

 

[TXoutback]

Thanks lutejones... it IS just a $20 knife, so I shouldn't be scared of putting it on the belt sander. I've got some finer grain belts that can do it slowly, and a dunk bucket.

 

[Obsessed with Edges]

Thanks lutejones... it IS just a $20 knife, so I shouldn't be scared of putting it on the belt sander. I've got some finer grain belts that can do it slowly, and a dunk bucket.

Use the stone, if you can. CV steel this thin will grind very easily on something like a simple AlOx or SiC hardware store oil stone (back/forth scrubbing stroke is very fast; use the stone with oil). Won't take long at all to thin the soddie's edge to better geometry. If you already have reservations about using the grinder, I'd just avoid it. It's not necessary for a job like this, on this blade.

FYI, I have both of the knives you're comparing (my Opi is a No. 08), and have thinned the edges on both of them.


David

 

[irona]

Use the stone, if you can. CV steel this thin will grind very easily on something like a simple AlOx or SiC hardware store oil stone (back/forth scrubbing stroke is very fast; use the stone with oil). Won't take long at all to thin the soddie's edge to better geometry. If you already have reservations about using the grinder, I'd just avoid it. It's not necessary for a job like this, on this blade.

FYI, I have both of the knives you're comparing (my Opi is a No. 08), and have thinned the edges on both of them.


David

A thinned edge on a Opinel?? How's that one slice?


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[Obsessed with Edges]

A thinned edge on a Opinel?? How's that one slice?


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Veeerrry nicely, thank you.

I did it just to see how it'd handle it. I have to be careful with it, though. It's kinda delicate now, a little more vulnerable to edge impacts or twisting in tough material. For something like wood-carving, it may be a little too thin. But it's lots of fun for food prep & such. After thinning it, I broke it in by slicing grapes in half, dropping them onto the upturned edge.


David

 

[traumkommode]

The Sodbuster has a hollow grind, so I'm interested to see what happens if you grind the flair where the cutting bevel starts down flat.

 

[sodak]

Or, if you only care about performance....

http://i137.photobucket.com/albums/q203/sodak_photos/inventory/sodbuster_zpsyl2rdtrn.jpg

It cuts better, but be aware that the steel is too soft to really support such a thin edge. You'll need a microbevel, and take care not to have any impacts. It cuts much better, but needs a much harder steel.

Now, if I can just find my thinned out opinel, I'll take a pic of that also.

 

[TXoutback]

Well, I took it to the belt grinder and did a little bit with 150 grit (the finest belt I had), then put it on the stones to smooth out my amateur grinding. It definitely has improved the and there's still some more room for work on the stone just to even it out. I'd say its on par with the Ontario now.

 

[irona]

Veeerrry nicely, thank you.

I did it just to see how it'd handle it. I have to be careful with it, though. It's kinda delicate now, a little more vulnerable to edge impacts or twisting in tough material. For something like wood-carving, it may be a little too thin. But it's lots of fun for food prep & such. After thinning it, I broke it in by slicing grapes in half, dropping them onto the upturned edge.


David

I was already shocked at how sharp I got my carbon Opi no. 8, but to think of an even thinner blade that can do that?

I might have to try that sometime soon...

 

[lutejones]

The Sodbuster has a hollow grind, so I'm interested to see what happens if you grind the flair where the cutting bevel starts down flat.

Something like this

The good news is that the patina soon covers it up

 

[irona]

Something like this

The good news is that the patina soon covers it up

Oh that's pretty interesting - I didn't know that case put out hollow ground knives


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[David Martin]

Well, I took it to the belt grinder and did a little bit with 150 grit (the finest belt I had), then put it on the stones to smooth out my amateur grinding. It definitely has improved the and there's still some more room for work on the stone just to even it out. I'd say its on par with the Ontario now.

Sure it will. Once you take off the flaring at the edge bevel-- making it a full hollow grind. This will improve cutting ability. DM

 

[irona]

Sure it will. Once you take off the flaring at the edge bevel-- making it a full hollow grind. This will improve cutting ability. DM

At this point I'm not sure if you guys want to modify a sodbuster or make a straight razor!


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[scott.livesey]

Thanks. I have a belt sander, but I'm planning to try doing it on a stone instead. I guess I should make a wooden angle guide at about 20° to start with.

i would do <10 degrees if you want to compare with the Opinel. I would try for a combined angle of 15-20 degrees then a 15 degree microbevel. The Opinel is probably only 0.05" at the spine with a full flat grind, so you are going to have to remove a lot of steel from the Case to get the same performance.
scott

 

[Obsessed with Edges]

From the factory anyway, Opinels are actually a shallow convex grind. It's subtle, but more easy to see with a straight-edge laid against the blade.


David

 

[Jason B.]

I would make it simple and buy a different model sod buster. The black handle model with markings on the blade and coarser blade finish seem to be ground very thin and take a razor sharp edge with ease.

 

[Obsessed with Edges]

I would make it simple and buy a different model sod buster. The black handle model with markings on the blade and coarser blade finish seem to be ground very thin and take a razor sharp edge with ease.

I have both, and they were both pretty good (at least) at the edge, as new. The factory grind on the stainless model (black one; 2137 SS) may've been one of the most impressive I've seen from Case, even out to the very tip, which was actually fully apexed to a very crisp, phonebook page-piercing point. I still thinned it a bit more, even so, and the existing factory edge made that easier from the start.

Having said that, the blades are both small enough and thin enough on these models, that some additional thinning doesn't really take much effort; maybe 10-15 minutes (or as little as 5 minutes, perhaps) of two-handed scrubbing on an appropriate stone of ~220-320 grit, for example can get it done. Either of an AlOx or SiC stone from Norton or ACE or Sears will simply EAT the CV steel, and the stainless isn't much more difficult on the same stones, maybe just a little slower to grind.

The large Sod Busters from Case (2138 & 3138 patterns) can take a bit more time to thin out, just due to the much thicker flat-ground blades. I made a project out of my 2138 SS soddie, thinning it's edge to a polished convex over a period of several sessions, a little bit at a time. I think I did much of that on sandpaper at the time, and maybe a little bit on a diamond hone as well, then polishing the convex on denim strops with AlOx and/or white rouge compound.


David