Mon Mar 18, 2013 11:13 am
I stated I couldn't imagine buying from any other than CKTG...but I bought both of those recent Konosuke HD 240s. Both, in hope that I would learn something about knives. That hope turned to reality over the weekend. I learned that one will cut carrots much better than the other. I just don't know why.
The "better" knife arrived in seemingly showroom condition - sharper than I expected. The seller stated that he had stropped on a 5K and a balsa strop resulting in a bit better edge that OOTB.
The other needed help and I, within my current skills, put a pretty good edge on it. When done, it would go through newspaper and arm hair in equal to its counterpart - perhaps a bit "slicker".
That said, I compared them side by side, slice by slice, and the former excelled over the latter. Couldn't detect any difference until the center of the carrot. One knife would glide through with a little 'peck' on the board while the other would "break" through with a little 'whack' on the board.
All that to get to my no surprise question - What's going on here?
Mon Mar 18, 2013 12:08 pm
It could be a couple of things.
With the one that doesn't cut as well, can you cut something larger like a big potato? Then let us know what's going on?
It could be a thicker shoulder, it could be a loose burr, it could be a bent wire edge, etc.
Mon Mar 18, 2013 3:31 pm
Had to leave for work and didn't have a big potato. I'll get back to you on this. Going to work is not as much a problem as not having a potato. I'll get back home at 2:15 AM but they roll up the sidewalks 'round here at at 7. I'll leave a note to the Ol' Axe to get some potatoes before she whips me out of the sack tomorrow.....
Mon Mar 18, 2013 4:37 pm
Wil wrote:....I'll leave a note to "the Ol' Axe" to get some potatoes before she whips me out of the sack tomorrow.....
If you address your note this way, we may hear from you again and we may not.
Tue Mar 19, 2013 7:15 am
The first (and only) thing I think of is illustrated in Ben Dale's (EP inventor) video where he cuts a carrot with a knife with a razor sharp edge but very high angles like you may want on a camping knife. The edge gets thick VERY fast. He cut a carrot with this knife and then with a thin putty knife with a flat side. Not a sharp edge at all. Because the putty knife was very thin it cut the carrot fine, maybe even easier than the knife with a thich edge/blade.
So, is there a big difference in blade thickness or edge angle on the two knives? This is the only thing I can think of because of my very limited experience.
Tue Mar 19, 2013 8:50 am
"If you address your note this way, we may hear from you again and we may not."
But I ain't THAT nuts!
OK, got a couple of potatoes - big'uns - 5 inches or so and fat in the middle. Cut "crossways" in the middle with both knives with the handle held between my fingers and no pressure other than the weight of the knife...same angle of attack and starting point as well. The "better" made it through the potato somewhere on the first pull stroke (pushing then pulling). The other made it through on the second pull. I didn't notice any extra force required to push and pull either knife. Neither did I notice any better spots along either blade.
Tue Mar 19, 2013 8:59 am
So it's probably a thick shoulder.
Try thinning the shoulder a bit and try again.
That the knife didn't cut through with the same amount of force and strokes tells me that the knife is thicker somewhere. If we're talking about identical knives, it's most likely the shoulder.
It could also be a wire edge. You can force the wire edge to show itself by scraping your edge across your fingers forcefully. It will bend the wire edge and you can see it in the light most times. Takes knowing what you're looking for though.
I would start with the shoulder though, and go from there.
Tue Mar 19, 2013 9:24 am
Is a wire edge the same as a burr except stronger - as if it would become a burr if you continue to grind the primary edge?
Is there a method of knowing how much thinning is enough? Perhaps better asked...Can I thin it too much such that it can't be fixed by a professional?
Tue Mar 19, 2013 10:06 am
I don't know of a standard definition for wire edge....but I use the term to describe:
A weak edge
It's not really the same as a burr in my mind. As you abrade the edge, the very tip of the edge can become fatigued and fail easier than the rest of the edge. As the knife is used, it can flip/flop slightly back and forth until it breaks off. It can become a burr I guess....but to me not really any more so than the rest of the edge. Again...this is my knowledge base and my understanding of terms.
Your second question is one of the main reasons I don't recommend very coarse stones to newbies. You can really eff up a knife with a coarse stone and a thinning session. With a 1k stone, you would have to do so much work to get to the point of screwing up the knife that you'd likely give up first. So the answer to your question is "Yes, you can go too far and do so easily with a coarse stone".
As a general rule, on a normal knife, if you double the bevel width with thinning, you're probably safe. This is not true for single bevel knives in the least.
Asymmetry plays a role when thinning a knife too...all the same rules still apply. However, others put more emphasis on this than I do. That's not to make light of the asymmetry discussion either....I know it's important but most people will never fully understand it or give a crap about it.
Wed Mar 20, 2013 12:08 pm
I'll wait for the weekend to thin it so I won't be rushed. I'll work with what I have (Shapton glass 500) to the extent that I'm comfortable and if it doesn't improve at all I'll send it to a pro and see what happens. At the least, I'll have something else to compare to.
Would you think the 500 for a few strokes and then continue with a green brick will keep me outta "ruination" space? Yes, you're supposed to know exactly what a "few strokes" is and supply a definitive answer.
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