The burr

I just wanted to make one comment about the "toothy edges" achieved by sharpening to a relatively coarse grit. This does result in an aggressive edge with micro-serrations. However, this type of edge is subject to damage with only light use. As these serrations deform and break, the edge will quickly degrade and require re-sharpening.

If you refine the edge out to a finer grit and get a smoother, straighter apex, then the edge will be more resistant to deformation and should retain its sharpness longer.

TedP
 
phillipsted said:
I just wanted to make one comment about the "toothy edges" achieved by sharpening to a relatively coarse grit. This does result in an aggressive edge with micro-serrations. However, this type of edge is subject to damage with only light use. As these serrations deform and break, the edge will quickly degrade and require re-sharpening.

If you refine the edge out to a finer grit and get a smoother, straighter apex, then the edge will be more resistant to deformation and should retain its sharpness longer.

TedP
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Many, myself included have found just the opposite depending on the chore. Choose the edge prep and inclusive angle as closely as possible for a given job and that's the edge that will last the longest. I've had a polished edge on my hatchet last for three or four weekend backpacking trips and still shave some arm hair. I've had the same edge strategy fail within days of use at work while a coarse edge lasted for weeks under the same conditions (all other things being equal). From what I have found with my own unscientific testing, pressure seems to be the number one killer of coarse edges, and friction seems to be the number one killer of polished edges. I can execute pressure cuts for a loong time with a fine edge depending on the material, and draw cuts for a loong time with a coarse edge - using fine edges to draw cut will dull them real fast, likewise chopping or press cutting with a rough edge starts poor and gets worse quickly.
 
Personally I believe it to be steel related, some steels like 1095 work well with a coarse edge while others like S30V tend to fail quicker.
 
knifenut1013 said:
Personally I believe it to be steel related, some steels like 1095 work well with a coarse edge while others like S30V tend to fail quicker.
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I have to chuckle - in my experience 1095 tends to hold a somewhat finer edge longer than a coarse one...

As I recall from Hardhearts CATRA testing it appeared the only reliable predictor of longevity (for the cutting done on the CATRA equipment) was inclusive edge angle. Any time there's a discussion on this topic I always try to qualify my comments by saying "What I've found" or "In my experience". Fairly subtle differences in edge prep, method of use, and material worked against can yield big changes in perceived and actual efficiency and longevity - I'm uncomfortable with blanket statements on this line of thought.
 
I have some inside knowledge of that test ;) and can say with confidence that edge performance is 95% angle.
The grit as you know makes the edge more task specific and to the users preference.

Interesting to hear your findings with 1095, at what grit or stone do you find balanced performance?
 
This is going to be a bit difficult to make a linear comparison, but probably somewhere around a 4k JIS or a touch finer. I noticed if I tried to stop at 1k or 1.2k ( or stropping with black compound on a firm backing), the edge just didn't seem to hold up as well. For most of my stainless edges this is where I'll stop for EDU - somewhat coarse but capable of just dry shaving stubble. This is a safe range to stop at IMHO for a multipurpose edge so it took me a while to accept that 1095 was bucking this approach. It performed well just not as long as many of my other knives, likewise if I polish it up too high.

I guess it depends on POV, to me a 6k is fairly polished, to someone else maybe somewhat coarse. To me coarse is 320 or under, 400 - 1000 is medium, 1200 - 4000 medium fine, and 6k up is extra fine etc.


I cannot be 100% sure of the 1095 steel in every case I noticed, but some of my inexpensive puukkos are of a similar composition (maybe) and seem to trend the same as the two knives I have listed as 1095. As I understand the carbon steel used by Mora is virtually the same as 1095 also, so am comparing against several manufactureres and a handful of examples.
 
So not too far off from my experience. Our thoughts on what defines a coarse and fine edge is somewhat different though, but not much.

Thinking back, my conclusions to the performance probably stem from being on one extreme or the other of the finished grit. I always used a mirror polish or a 300 grit stone to sharpen 1095 so its probably a perception from that.
 
I experiment too much - sometimes I can't even remember how I finished an edge off if I haven't used a particular knife in awhile. For a time I was jotting this down in a notebook but am not disciplined enough to keep it up. Now I generally assume how the edge was finished based on the type of blade (intended use) and what type of steel.
 
For whatever it is worth, I have arrived at a happy medium. On one side, I have a love of the quest for the perfect edge and on the other, a practical working sharpness. Nothing impresses like a scary sharp knife, popping hairs, push-cutting toilet paper, etc... But there is also something to be said about simple(bordering expedient) means for quickly getting your knife to meet all cutting expectations. I am fascinated with pushing the envelope to squeeze every ounce of potential but at the same time, driven by real World practical application. The two are not always in alignment. It is a compromise that, in my opinion, can be just as fulfilling.
 
Rick Marchand said:
For whatever it is worth, I have arrived at a happy medium. On one side, I have a love of the quest for the perfect edge and on the other, a practical working sharpness. Nothing impresses like a scary sharp knife, popping hairs, push-cutting toilet paper, etc... But there is also something to be said about simple(bordering expedient) means for quickly getting your knife to meet all cutting expectations. I am fascinated with pushing the envelope to squeeze every ounce of potential but at the same time, driven by real World practical application. The two are not always in alignment. It is a compromise that, in my opinion, can be just as fulfilling.
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I have to agree with this. Most of my tinkering is trying to find faster and more simple methods of reproducing edge characteristics I can get with other less convenient means. I also find that my super duper edges, at whatever grind I stop at (coarse, med, or fine) will rapidly 'deteriorate' to be just coarse, med, or fine - all the method-specific characteristics tend to fade fairly quickly under use anyway. But once you get that edge you were looking for its hard to be happy with an edge that only does what you needed it to do.

Did not realize you were in NS, have vacationed there a couple times and stopped at Mahone Bay. Beautiful Province, we didn't want to leave. The wife and I went as far as getting paperwork to apply for citizenship but never filled it out...

HH
 
Well Knifenut!, few years after the original post, newbies (like me) reading it and found it very helpful and informative. Thank you!
 
Found a good little video that I though would go well in the thread.

[video=youtube;EVYEB3HHu6M]https://www.youtube.com/watch?app=desktop&persist_app=1&v=EVYEB3HHu6M[/video]
 
After seeing the other vid from the "Grinding Doc" in another thread (about loading/swarf formation), I'd looked this guy up on his YouTube channel. Saw this vid & liked it. Good idea (great, actually) in linking it into this thread, Jason. It fits perfectly. :thumbup:

I'm encouraged by his recommendation to use 'softer'-bound media with more angular & friable grit. This is a textbook description of the qualities I've come to like in SiC wet/dry paper which, coincidentally, really reduced the issues I was seeing with burrs in very ductile steels. Glad to know I wasn't imagining this. :)


David
 
Great to see this thread being still alive! Good video, thanks for sharing Jason!
 
Good discussion and sharing of information is a gift to all who stumble across it in the future, as I have. Many thanks.
 
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