Author Topic: Wire edge?  (Read 171 times)

Offline bgtklbx

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Wire edge?
« on: August 01, 2020, 10:26:34 pm »
Hello Tormek pros. I sharpened a mid grade kitchen butcher knife today and had the following experience. The edge had been previously sharpened by me at 12 dps. It had dulled from normal use. I decided to use my new CBN wheels and they worked great. Apexed using a 400 then one pass on the 1000 cbn.
I then broke my normal protocol and finished on a new 4000 Tormek japanese stone. The JS250. I did it edge trailing using the frontal base and software, at the edge angle. It felt sharp on the thumbnail, but the BESS went to 900. WOW, not good. So i suspected a wire edge??
I then went to my 2 paper wheels at the edge angle 10 micron diamonds and then 5 micron diamond, went to rock hard felt with 1 micron diamond at 2 degrees higher. Now its 135 BESS. I went 2.5 degrees higher on the felt and it was a little better and ended on paper wheel at edge angle using green chromium oxide. 110 BESS, cuts paper super clean. So i stopped since its kind of a cheap knife. Any ideas on the super dull reading after the 4000 stone? Thanks for any ideas or input.

Offline cbwx34

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Re: Wire edge?
« Reply #1 on: August 01, 2020, 11:30:47 pm »
Hello Tormek pros. I sharpened a mid grade kitchen butcher knife today and had the following experience. The edge had been previously sharpened by me at 12 dps. It had dulled from normal use. I decided to use my new CBN wheels and they worked great. Apexed using a 400 then one pass on the 1000 cbn.
I then broke my normal protocol and finished on a new 4000 Tormek japanese stone. The JS250. I did it edge trailing using the frontal base and software, at the edge angle. It felt sharp on the thumbnail, but the BESS went to 900. WOW, not good. So i suspected a wire edge??
I then went to my 2 paper wheels at the edge angle 10 micron diamonds and then 5 micron diamond, went to rock hard felt with 1 micron diamond at 2 degrees higher. Now its 135 BESS. I went 2.5 degrees higher on the felt and it was a little better and ended on paper wheel at edge angle using green chromium oxide. 110 BESS, cuts paper super clean. So i stopped since its kind of a cheap knife. Any ideas on the super dull reading after the 4000 stone? Thanks for any ideas or input.

I suspect you're right.  :)

Edge trailing at the same angle on the SJ wheel, most likely won't remove the burr, especially on a "cheap" knife.

If you want to experiment removing the burr just on the SJ wheel, try a couple of alternating, edge leading passes (or you can try edge trailing), with very light pressure, 2-4 deg. higher than the sharpened angle, and see what happens.  Light pressure.  The goal is to remove the burr... not polish.

Did I mention very light pressure? ;)

Offline Hannsi1957

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Re: Wire edge?
« Reply #2 on: August 02, 2020, 12:12:51 am »
I guess you could say you got lost.
a middle class  knife dont need a 1000 grit cbn. after the 400 grit cbn go to the felt wheel with about 1 degree more. then go to the leather with the right degree and you will probably get better results than after all the work you have done.
now of course the reasoning......... 2 things i would never do. sharpening a middle class knife with 12 degrees and a high end treatment like you tried it......why????? the steel is much too soft for such a treatment, the cutting edge with 12 degrees is much too fine so you don't remove the burr but you keep putting it back. don't experiment with such knives but if you want them to be very sharp for the moment sharpen 15 degrees but even better with middle class knives that are in daily use an angle of 20 degrees. this keeps its stability and sharpness for a long time.

cheers Hanns

Offline bgtklbx

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Re: Wire edge?
« Reply #3 on: August 02, 2020, 12:45:11 am »
Thanks for the great replies. A constant learning process. Anyone else feel free to add your thoughts.

Offline brute

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Re: Wire edge?
« Reply #4 on: August 02, 2020, 03:31:34 pm »
Hannsi:
Great advise.

Offline jvh

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Re: Wire edge?
« Reply #5 on: August 02, 2020, 10:19:50 pm »
Hello Tormek pros. I sharpened a mid grade kitchen butcher knife today and had the following experience. The edge had been previously sharpened by me at 12 dps. It had dulled from normal use. I decided to use my new CBN wheels and they worked great. Apexed using a 400 then one pass on the 1000 cbn.
I then broke my normal protocol and finished on a new 4000 Tormek japanese stone. The JS250. I did it edge trailing using the frontal base and software, at the edge angle. It felt sharp on the thumbnail, but the BESS went to 900. WOW, not good. So i suspected a wire edge??
I then went to my 2 paper wheels at the edge angle 10 micron diamonds and then 5 micron diamond, went to rock hard felt with 1 micron diamond at 2 degrees higher. Now its 135 BESS. I went 2.5 degrees higher on the felt and it was a little better and ended on paper wheel at edge angle using green chromium oxide. 110 BESS, cuts paper super clean. So i stopped since its kind of a cheap knife. Any ideas on the super dull reading after the 4000 stone? Thanks for any ideas or input.


Hello,

cb and Hannsi have already said the most important thing.

In short: CBN 400, CBN 1000, SJ-250, 2 paper wheels, rock hard felt wheel, FVB, grinding towards the edge, grinding away the edge. Too many steps, too many possible problems in each one.

IMHO:
1. Trust no one. ;) Verify all steps with your own tests. Change procedure if results are bad (grinding/honing angles, pressure, wheels etc.).

2. On normal circumstances use grinding towards to edge (small burr, more easily removable). FVB and grinding away from edge use if there is no other option only (I haven't used mine since I bought the US-430).

3. 12 dps for knives deserves its own topic.
Just my experiences - very weak edge if grinded without microbevel, this applies to all steels! Very short edge retention, contact with bone can chip the edge easily, contact with cutting board dulls the blade in short time. Of course, usable for vegetable, boneless meat etc. Everything changes with microbevel (36-40°) but is it necessary for everyday used kitchen knife?

Some tests made Pavol Sandor, unfortunately it's in Slovak only but results table has english descriptions. I know that the tests were done by rope cutting but what is the difference between rope and wooden cutting board?
To be honest, there is also disclaimer: "The tests have no absolute informative value! They are influenced by subjective factors...etc.". Very nice for videos that contain tests, microscopy, explanation, etc. Deal with it as you wish, the decision is up to you.

Test results
Video 1, Video 2, Video 3, Video 4


jvh