Farm Life

tiguy7 said:
The propensity of an edge to roll is not determined by its sharpness, dullness, or how recently it has been restored. Rather the likeliness of new deformation will be determined by the number and strengths of fresh insults to the edge. When working with food (soft stuff), the edge will be fine until a bone is whacked. How hard is the bone? At what angle was it struck? How hard was the strike? How many times was it struck?
A dull edge will roll just as readily as a sharp one. Meat cleavers have obtuse edge angles in anticipation of bone strikes. Fine edged cutlery.. not so much.
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yes Sir. I meant more the factory edge which was made using a belt sander and some heat that may or may not depending on who do the sharpening and how much heat got to the edge......compromise the steel...vs. sharpening and getting to new steel and how it holds up. we shall see if there is any effect or not in David's real world knife use testing.
 
I have watched knives being sharpened at the Buck factory and saw no evidence of overheating the bevel or micro edge. When a knife is left on the belt too long, the contact area turns red (glows) and after cooling turns blue. The CATRA test would uncover any production degraded by poor sharpeneing technique. It helps to change belts often and spit out your gum so as to pay close attention to the work at hand. The proper outcome of (it’s all in the wrist) is two matching uniform bevels.
If an edge were overheated in grinding, the hardness would be lowered, making the edge more likely to roll.
 
I have some other comments but allow me to address this ^. Not every knife is run on the CATRA as it requires time to do this. My 110 w/ s90v steel when it arrived had very nice even bevels. I know what an over heated area looks like and this was not in my knife. DM
 
tiguy7 said:
A steeling rod or ceramic rod would not work for straightening the rolled edge. A brass or mild steel rod immobilized by a vise allows you to apply a lot of pressure with both hands to the deformed area edge trailing. The Vanadium Carbides do not affect the process. The ability to move the rolled edge is determined by the strength of the crystal lattice structure of the blade (HRC) rather than the inclusions in that lattice.
Once the rolled portion is brought into “line”, the edge can be touched up by sharpening or steeling or some combination thereof.
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I can agree with this as a premise. Somewhat. Your saying a weaker, softer metal is capable of grabbing, holding and straightening a very tough, harder metal.? If you put enough pressure against it. Perhaps the thin edge bevel is weaker than I think. DM
 
st8yd said:
Hey Dave,
Have you tried the Buck 539 Open season small game?
Aside from my general preference of the 6" blade for processing/boning, I have enjoyed using this knife.
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No, I haven't tried that one Yet. I have used the fore runner. The earlier first Selector V52. It had a skinning blade that has a very good shape and grind lines. Cross section / blade profile and the belly is good too. Plus, it is of 425M steel and 3 3/4" long. Which works very good. DM
 
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David Martin said:
We put 3 more Cornish in the freezer this morning. Ole Blue is certainly into it's vanadium edge at 7. No edge rolling. We have 5 more which I'll work on this afternoon. I can tell for my liking after 12 the edge will be a sluggish type and I could call it good and touch it up. I could likely do
10 more at this point. And those last few most guys here would not enjoy the degraded edge. If I were trying to get the elk skinned before dark, I would continue, just as long at it would cut. But I would not like the way it was cutting. I'm on a project that I can afford to stop and
touch up the edge before continuing. So, it would be the users call and I'm certainly giving you the information we were after. DM
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I have had the opportunity to work along with professional butchers and they keep a steel clipped to their side and hit it regularly to roll the edge back as they work. Accordingly when I get the knives out to process the steel comes out to. When hitting it on the steel doesn't help any more then it's time for the stones.
 
The 539 isn't a selector, its the smaller fixed blade. Ya oughta get one and give it a try. I got it as one of my BCCI discounts, as I couldn't decide on anything else and was a little reluctant about it. But I really like it. Havn't gotten use to the sheath although I don't wear it anyway, just use it to keep the knife safe.
Buck 539.jpg
 
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tiguy7 said:
The propensity of an edge to roll is not determined by its sharpness, dullness, or how recently it has been restored. Rather the likeliness of new deformation will be determined by the number and strengths of fresh insults to the edge. When working with food (soft stuff), the edge will be fine until a bone is whacked. How hard is the bone? At what angle was it struck? How hard was the strike? How many times was it struck?
A dull edge will roll just as readily as a sharp one. Meat cleavers have obtuse edge angles in anticipation of bone strikes. Fine edged cutlery.. not so much.
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Yes, not leaving out the better steel material, edge angle and heat treat. The knives I have w/ 420hc steel, I've noticed will roll quicker than
s90v during use. So, steel structure and matrix play a role. As well as the other 2 items. Then yes, 'the number of insults'. DM
 
st8, pardon me. I was thinking of a different model. I have been wanting to get the Cabelas Alaskan Guide model fillet knife with the coated blade and s30v steel. My 110 Cabelas w/ the blade coating is a first rate knife. DM
 
st8yd said:
I have had the opportunity to work along with professional butchers and they keep a steel clipped to their side and hit it regularly to roll the edge back as they work. Accordingly when I get the knives out to process the steel comes out to. When hitting it on the steel doesn't help any more then it's time for the stones.
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Yes, on commercial grade knives their steel is usually 420 and can be straightened several times using a steel. Which can take a butcher farther
into his work day. But the time will come when a steel no longer works and a stone must be used to create a new edge. I usually work mine on a loaded strop to extend it's life. This will work 2-3 times, before I must take it to a stone. But with a steel like s90v even a loaded strop doesn't work so good. DM
 
tiguy7 said:
I have watched knives being sharpened at the Buck factory and saw no evidence of overheating the bevel or micro edge. When a knife is left on the belt too long, the contact area turns red (glows) and after cooling turns blue. The CATRA test would uncover any production degraded by poor sharpeneing technique. It helps to change belts often and spit out your gum so as to pay close attention to the work at hand. The proper outcome of (it’s all in the wrist) is two matching uniform bevels.
If an edge were overheated in grinding, the hardness would be lowered, making the edge more likely to roll.
Click to expand...

I've always found....once on gets to newer steel from a factory sharpen it shows better results of what it will or won't do. sorry shouldn't have made it look the factory does anything wrong. I'm a terrible wordsmith. as I've been following David's process I realized he has new edge and was wondering how the rolling from lots of use would do.... less or same?

David Martin said:
I have some other comments but allow me to address this ^. Not every knife is run on the CATRA as it requires time to do this. My 110 w/ s90v steel when it arrived had very nice even bevels. I know what an over heated area looks like and this was not in my knife. DM
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wasn't implying that Sir. more just how new edge would perform with newer steel exposed. in your testing and use...same or less rolling in similar tasks.
 
I think I understand what you're saying. Correct me if not. A 'new edge' could be over worked. Not burned. This would cause metal fatigue. Especially, when I began putting it to the test. This is my 3rd test. I don't think this condition was present. It took some working for this rolling to appear. Which I thought was from normal use. I was trying to avoid hitting bones. (finger size) Still, I could have a little bit. I know meat processing and don't have to think about it, I just go to it. I don't hesitate or stop unless I see something or my wife out of the normal. We've done this enough and know what to watch for. Even repeated cutting through ribs could cause metal fatigue. (15 ribs per side = 30 per bird) X 12= 360. Just saying I cut a lot of ribs with it. DM
 
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David Martin said:
Yes, not leaving out the better steel material, edge angle and heat treat. The knives I have w/ 420hc steel, I've noticed will roll quicker than
s90v during use. So, steel structure and matrix play a role. As well as the other 2 items. Then yes, 'the number of insults'. DM
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The 420hc will roll quicker than the S-90-V because it has less Carbon and cannot achieve as high of an HRC. 420HC has 0.46% C. S-90-V has 2.3% C, about 5X as much. The Carbides in the matrix do not contribute significantly to the resistance to edge rolling. They are inclusions in the structure but not part of it. The edge angles on the 420 and S90 Bucks will be the same. A proper heat treat will give the S90 an advantage over the 420 in HRC. The steel structure is the matrix/lattice crystal framework which resists deformation. The non-ferrous Carbides are just along for the ride.
 
jbmonkey said:
I've always found....once on gets to newer steel from a factory sharpen it shows better results of what it will or won't do. sorry shouldn't have made it look the factory does anything wrong. I'm a terrible wordsmith. as I've been following David's process I realized he has new edge and was wondering how the rolling from lots of use would do.... less or same?



wasn't implying that Sir. more just how new edge would perform with newer steel exposed. in your testing and use...same or less rolling in similar tasks.
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Since factory edges, for the most part, are applied on one belt running over a contact wheel with only one grit employed, I would guess that almost any post factory sharpening would improve the performance of the factory edge. I wouldn’t ascribe this improvement to new steel being exposed by the removal of bad steel, but rather to an improvement to the refinement and/or geometry of the original edge.
 
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David Martin said:
I can agree with this as a premise. Somewhat. Your saying a weaker, softer metal is capable of grabbing, holding and straightening a very tough, harder metal.? If you put enough pressure against it. Perhaps the thin edge bevel is weaker than I think. DM
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The edge metal being returned to the “normal” position does not need to be grabbed or held by the brass rod, merely nudged. Bladesmiths use the brass rod to test for the proper heat treatment of their blades. The same rod can be used to repair a damaged edge. This works on knives in the 60 HRC vicinity.
 
David Martin said:
I think I understand what you're saying. Correct me if not. A 'new edge' could be over worked. Not burned. This would cause metal fatigue. Especially, when I began putting it to the test. I don't think this condition was present. It took some working for this rolling to appear. Which I thought was from normal use. I was trying to avoid hitting bones. (finger size) Still, I could have a little bit. I know meat processing and don't have to think about it, I just go to it. I don't hesitate or stop unless I see something or my wife out of the normal. We've done this enough and know what to watch for. Even repeated cutting through ribs could cause metal fatigue. (15 ribs per side = 30 per bird) X 12= 360. DM
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I don’t think that metal fatique comes into play on a properly made steel knife blade. We’re not talking about 1 mllion miles on a vibrating airplane wing. It seems as implausible as work hardening.
I watched slaughterhouse butchers debone dairy cows which were hung as front and rear halves. They used a 6” boner in one hand and steel in the other. 3 cuts- 1 steel. They could take the meat off the bone (1/2 of a cow) in one piece and drop it into a wooden crate.
 
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Yes, the matrix and those elements hardened in it, (i.e. vanadium carbides) will give an advantage to that steel in cutting and resisting deformation.
If you observed Dairy cows being brought to slaughter, those are Canners, grade. A old cow who used up her useful life and now her end result
is dog food. They are thin and tough to process. And they are using a commercial grade boning knife of 420 steel which can be bent back into
place with a steel. Not in the same kettle of fish as our example here.
Your old diagram looks like your using a drawing motion to straighten the rolled edge. Not a edge trailing lift. DM
 
Ok, a good photo. But what have you actually processed with them? Used them to gain personal experience and knowledge in. Specifically toward knowing what is occurring at the edge to bring about rolling. Then how to fix it. DM
 
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Once my s90v Buck gets rolled again I'll try the brass rod. These are available at my hardware store. DM
 
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