SS Sod Buster edge help

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kodiak

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Dec 24, 2002
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Hi. I have a gentleman at work I recently got to carry a knife. I gave him a Case SS Sod Buster Jr. He really loves it but he told me "it doesn't hold an edge worth a s..t!" So I had to fix this.

He said he abuses the knife a little. Uses the blade sometimes to literally bust sod!

First: I wanted to give him a CV Sod Buster Jr. He didn't like the Yellow handles.

Second: I offered to switch out the CV blade and put it in the black handle. He said he bought the knife because of the Sod Buster logo on the blade.

So, I would like to know what kind of edge you would put on for utility purposes. I am using a Sharpmaker. I thought I would put a 30 Deg. relief and a 40 Deg. edge. Is that the best I can do for him? Thanks for your input.
 
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I think he is being a little unreasonable, he complains about the performance but he bought the knife for looks? No steel on earth is going to stay sharp for long if he is cutting dirt with it, best thing you could do for him would be to teach him how to sharpen a knife or have a dedicated sod knife (I don't think a dirt knife has to be very sharp). A more obtuse edge will help some, but minerals are hard on an edge.

What was he using to bust sod before you got him a knife?
 
I agree with BJE. Thicker angle for the soddie and get a dedicated Sod cutting knife.

As far as sharpening goes, the best you can do is 40° inclusive and leave out the edge thinning. You need as much blade as possible. I don't use thinner angles on soft steels. They are not strong enough to resist rolling.

Cutting sod is not conducive to edge retention. Too much gravel and small rocks. It's like cutting sandpaper. Get a dedicated knife for that.

Tru-Sharp is not real great for edge retention. CV is a bit better, but still has lesser edge retention than Buck 420HC. Those Case alloys are run pretty soft (55-56 HRC). They take a fantastic edge without much effort, but do not retain it as well as many other alloys.

IIRC Queen makes a Sod Buster in D2. It'll likely take a while to put a good edge on it, but it'll hold it WAYYYYY longer than Tru-Sharp.
 
knarfeng said:
As far as sharpening goes, the best you can do is 40° inclusive and leave out the edge thinning. You need as much blade as possible. I don't use thinner angles on soft steels. They are not strong enough to resist rolling.
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Totally disagree. Thin edge bevels don't make edges roll. Lateral forces and weakened steel do (steel weakened due to lost temper and such.) The same kind of forces would make a similarly thin bevel of a harder steel also fail. But in the latter case, the failure would more likely be chipping rather than rolling.

A 40° bevel makes for a decent spade. Which may be what is called for. But it also makes for a mediocre knife, particularly if that angle is used on the kind of thick bevels those Case knives come with.

I say go in the opposite direction. A zero edge, with maybe a micro bevel, will cut better, for longer, even when cutting very abrasive materials. And be easier to sharpen, too. Of course, that would most likely mean sacrificing the blade etching. Those sodbusters are full hollow grind, no? Normally, I would lay the blade flat on the stone/belt and grind away until there was no edge bevel left. This treatment makes a remarkable cutter of any steel, even the softest steel, as long as the temper isn't lost.

Ultimately, there may be no solution to this problem unless he agrees to get a dedicated abuser and a dedicated slicer.
 
When you have less steel behind the edge it is easier to roll and chip. Softer steels tend to roll first, I have seen this first hand with SAK's I thinned out beyond what the steel could handle for my uses, the edges would roll if there was any stress present while cutting.

It takes a very long time to zero grind a blade by hand on a stone and he has already expressed that the guy want to keep the etch.

Also, Case knives have some of the best and thinnest edges I have ever seen on a production slip-joint knife, they are the only traditional company that doesn't require edge thinning out of the box IMO. They usually have a burr on the edge, but that is a far cry from obtuse bevels, my opinion is based on buying, selling, trading, and handling probably a hundred different Case knives from different years.

Micro beveling will help, but if the metal is very thin behind the edge, it will probably still roll under abusive conditions.
 
I already said I agree with BJE.

Case runs their Tru-sharp soft (55-56 HRC). Soft steels roll more easily. That calls for a thicker edge angle so that there is more steel in the edge.
 
For cutting dirt the edge is not as important as the blade geometry. A thin blade with a strong spine will work best. DO put an edge on it, but there's no need to take it any further than an extra-coarse grit. Something like a scythe sharpening stone would do the job nicely.

657872_Scythe_Stone.jpg
 
knarfeng said:
Case runs their Tru-sharp soft (55-56 HRC). Soft steels roll more easily. That calls for a thicker edge angle so that there is more steel in the edge.
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Again, no. Opinels and Douk Douks are well known for their very thin edges and relatively soft steel. They are not particularly known for rolled edges. Vivi's experiences documented on many of his threads also attest to the usefulness of very thin edges. Cliff Stamp's tests do the same, attesting that even the crappiest steel reaps benefits of very thin grinding.

Thicker profiles and edge bevels are good for lateral strength. Not good for cutting. That may be what's called for with the OP. But it's very much a compromise when it comes to cutting.

BJE said:
Also, Case knives have some of the best and thinnest edges I have ever seen on a production slip-joint knife, they are the only traditional company that doesn't require edge thinning out of the box IMO.
Click to expand...

I'm seeing different Case knives than you. I have not seen any with what I would call particularly thin or acute edge bevels. None that could not easily be improved.

Micro beveling works best when the profile is already thin and acute. It doesn't help very much for a thick 40° edge.
 
I haven't tested Opinels. I have never run a hardness test on one, I have not seen a spec for their hardness, I have not tested the edge retention.
I have no data, so I cannot comment.

I have tested Case Tru-Sharp. The hardness of mine was 55. I keep it at 40° inclusive because it deformed so much when I tested the edge cutting manila rope.
 
Thank you guys for all of your experiences! It sure makes for good reading and good education. :D
 
I can really appreciate thinned edges, but there is a time and place for them. I have problems with my Opinel's edge rolling pretty easily and it is far from a zero grind although it is arguably one of my sharper knives. My Fallkniven U2 on the other hand has a very thin edge, almost a zero grind and I have no problems with rolling on that one, the Rc is around 63 on the U2.

For my daily users with CV or 1095 run around 55-57 Rc, I don't like any thicker than a 40 degree total angle or less than a 25 degree total angle. Too thick and I give up cutting performance and too thin I give up edge durability. For heavy use such as cutting dirt, performance won't be as important as durability, when you aren't splitting atoms and you are merely separating materials on a much larger scale it doen't take a scalpel.
 
Double post.. having computer trouble.
 
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