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+--- Thread: Work Sharp Cullinary (/showthread.php?tid=152)
RE: Work Sharp Cullinary - grepper - 08-19-2017
I was really curious about using a Scotch-Brite belt for deburring, so I just did the following on the Kally a few minutes ago:
Sharpened using a Cubitron 150 grit belt and created a burr. Here you can see the burr. The black line at the right is a marker line so the same area of the blade could be observed each time:
[attachment=272]
Did 3 light pressure passes, alternating sides each pass with a blue 3M Scotch-Brite belt. After the Scotch-Brite belt there was still burr, and the blade was not sharp. It would not hang on my fingernail, and it did not feel sharp to my fingers. I didn’t bother to take a sharpness reading.
I examined the edge using a 10X loupe under a good light being careful to shine the light from different angles. Even though there was still remaining bur, I was not able to see with it the loupe. It looked clean. Here is a picture of the blade. The marker line is not visible in the image, but it is just out of frame below and it is the same are of the blade. There is still burr:
[attachment=273]
So I finished with a leather belt. The leather belt removed the burr. The blade felt sharp, hung on my nail, and final sharpness was 150 gf on the PT50B. I was a little surprised that the Scotch-Brite belt did not dull the edge. While it did not dull it, it did not remove the entire burr either. Here is the final edge with the burr removed using the leather belt:
[attachment=274]
Conclusions:
The Scotch-Brite belt did diminish the burr.
The Scotch-Brite belt did not remove the entire burr.
The Scotch-Brite belt did not seem to dull the edge.
Interestingly, after the Scotch-Brite belt, I could not see the burr with a 10X loupe. Maybe I should have spent more time at it and looked more carefully.
The blade was obviously sharper after the burr was completely removed using the leather belt.
Unanswered question:
While the Scotch-Brite belt did diminish the burr, I don’t know if it really helped or if it was just an unnecessary step. I could have accomplished the same degree of burr removal by just skipping the Scotch-Brite belt and going straight to the leather belt.
Disclaimer:
This was just one test. It is neither extensive nor conclusive. Nonetheless, that is what happened and what I observed. I guess it's another take from it what you will kind of thing.
RE: Work Sharp Cullinary - Rupert Lucius - 08-19-2017
Thanks for the excellent report - considering adjusting my routine
Rupert uses a 120 grit belt, moves to a ScotchBrite (Blue) belt (appx 150 grit) and to the magic loose sewn 8 inch dia cotton buff at 1750/1800 RPM - operating without compounds (clean wheel).
Bed time for me -
As always and
Thanks
Rupert
RE: Work Sharp Cullinary - grepper - 08-19-2017
When I experimented with using a magic loose sewn cotton buffing wheel for burr removal it did not pan out for me. I was not able to get it to remove burr. If memory serves, there was some minor burr removal, but mostly it just did some straightened the the burr and polished the bevel.
I'm not sure of your thinking, but If you are thinking of adjusting your routine I would be dubious of simply skipping the Scotch-Brite step and going directly to the buffing wheel. If that is what you mean by adjusting your routine, I would replace the Scotch-Brite step with with something else like a leather belt or wheel.
Then again, you may be doing something differently that I am, and if what you are doing is working it's hard to argue with that! You know... if it ain't broke, don't try to fix it!
If you look very carefully, even after the leather belt there is still a very small amount of burr. It's not much, but a few more passes on the leather belt would have been more complete. There is just a small amount of rolled burr in some areas of the edge. You can see it where the arrows point and in other areas too. Close examination is required, but it's there.
[attachment=275]
Here is a closer image of my crappy job of burr removal with the leather belt. Admittedly this is a very small amount of burr and it would not be visible with just a loupe. But nonetheless, there it is! Yuck!
[attachment=276]
RE: Work Sharp Cullinary - grepper - 08-21-2017
Thanks to Mr. Rupert for passing this along. It is an interesting thread. I’m looking FW to when some forum members here get one and give it some good tests and reviews. The entire thread is interesting.
http://www.bladeforums.com/threads/microforge-technology.1474900/page-2#post-17395078
Here they say that the average depth of the MicroForge edge is ~5 microns and discuss what it takes to remove the MicroForge edge and what happens if you do it a bunch if times.
http://www.bladeforums.com/threads/microforge-technology.1474900/page-2#post-17387496
RE: Work Sharp Cullinary - Mark Reich - 08-24-2017
You have to get up mighty early if you want to beat Mr Rupert to the punch! I'm continually amazed with the things he finds and shares with me. Exactly as he did with EOU, actually.
I've spent a couple hours researching this. Text messaging with Work Sharp finally got me in the ballpark. Indeed, there is some sort of carbide wheel that dents the blade. That seems to be the crux of the entire concept. After sharpening, the blade is uniformly dented on the carbide wheel, then you just touch up on the ceramic rod again.
If you have to start with a sharp knife, then dent it, then resharpen it, are you you actually gaining? If the dents are only around 5 microns deep, that would be like 3,500 grit "teeth", while it looks like they are closer to 35 grit dents.
I'm sorry, but it seems like something is not adding up, IMHO.
RE: Work Sharp Cullinary - grepper - 08-25-2017
(08-18-2017, 01:58 AM)Jan Wrote: Really very interesting topic. Thanks for opening this thread Mr. Rupert! Mr. Grepper and Mr. Work Sharp Culinary, thanks for your contributions.
I am not an advocate of a "toothy" edge, but I am recognising its superior performance and edge retention. MicroForge technology is very interesting to me because it is a trade-off between smooth and toothy edge. In my thinking the micro facets are created in a way that does not reduce the strength of the edge.
In my understanding the MicroForge technology creates the micro facets via the plastic deformation of the edge. This process is also called work hardening because it may strengthen the steel in a close vicinity of the micro facets.
Jan
P.S.: As Mr Rupert said: Hope this is that "holy grail" edge.
Mr. Jan, you uttered a curious statement, "I am not an advocate of a "toothy" edge, but I am recognizing its superior performance and edge retention." I am wondering if you would be so kind as to elaborate on your thoughts.
It seems that on one hand you don't like a toothy edge, but on the other see its advantages. I think you mentioned in a previous post somewhere that scratches weaken the metal under the scratch. Is it because of the metallurgy of the thing that you have reservations concerning a toothy edge?
RE: Work Sharp Cullinary - Jan - 08-26-2017
Yes, Mr. Grepper, you understand my position to a toothy edge well. I hope that my statement is not internally inconsistent.
My reservations concerning a toothy edge are really based on metallurgical consequences of its generation. As I have already posted, a scratch near the edge which has a width of some 5 micron should reduce the strength of the cutting edge because it locally disrupts the regular steel lattice to a depth which is equal to the edge apex width.
It is a riddle for me how it is possible that the individual teeth of the toothy edge do not serve as a stress raisers where the steel fails. It is known, that a steel object is stronger when force is evenly distributed over its area. When the area is reduced, e.g. by a cracks or teeth, than spots with a localized increase in stress are generated. The steel should fail when this concentrated stress exceeds the material's cohesive strength.
Because the failure does not occur, we are probably still below the fracture strength of the steel.
Jan
RE: Work Sharp Cullinary - grepper - 08-26-2017
I know very little about metallurgy so I appreciate and find the posts about it very interesting and informative.
That said, sometimes I wonder how really applicable it is to basic everyday using a knife. By that I mean for all intents and purposes in normal use a blade is going to dull and need maintenance. For the most part, there is little difference between blades as far as that is concerned. One blade may stay slightly sharper/more useful maybe 10%-20% longer, but for general use, to me, that is really not a big deal. Sooner or a little later it will require maintenance.
Mr. Jan, I found your last post enlightening. I had always learned that a smooth edge was stronger and more durable because, as you stated, the edge is fully supported along its entire length and "a steel object is stronger when force is evenly distributed over its area." To me that seemed to make perfect sense. A no-brainer. I mean, duh!
But after a while I got fed up with smooth edges. They work great right after being sharpened but degrade in usefulness very quickly. So, how can this be? Surely it makes perfect sense that a well supported smooth edge must be stronger than a toothy edge. How can those little unsupported "teeth" possible work so well and have superior edge retention from a metallurgic point of view?
Then you most perspicaciously uttered, "Because the failure does not occur, we are probably still below the fracture strength of the steel."
That makes sense! Thank you Mr. Jan! For some odd reason I had not thought of it that way. While a fully supported smooth edge may be stronger, in this case, for what a general purpose knife is used for, the steel is strong enough that any strength reduction of a toothy edge is not of practical consequence. A wax candle is not as strong as a steel rod, but it works great for sticking into the top of a birthday cake.
Finally I can stop endlessly worrying and get a good night's sleep, blissfully enjoying all the benefits of a wonderfully toothy edge.
(No doubt someone will come along and say, not so fast grepper! Have you considered... )
RE: Work Sharp Cullinary - Jan - 08-26-2017
Mr. Grepper, I rejoice with you and hope that we do not remain in blissful ignorance of some more plausible explanation.
Jan
RE: Work Sharp Cullinary - grepper - 08-26-2017
Am I interpreting what you are saying correctly Mr. Jan? That steel is hard enough that weakening created by a toothy edge is not of great consequence simply because the steel is hard enough for the task at hand?
Blissful ignorance is good. Pesky science is bad. Very bad. It generally gets in the way of blissful ignorance.
