a good video for perfectionist knife sharpeners

[Ken S]

I found the technique and dedication used in this video outstanding.

https://youtu.be/XA4FR4Fq3K4

Ken

[Thy Will Be Done]

Interesting video.  I wonder if the chips were left from the damage he noted early in the video about it coming to him with chips.  I will say that he lost me when he put the knife on the buffer.  To my understanding, any claims of 'high end sharpening' go out the window in all likelihood when you use such high-RPM dry grinding equipment as it takes but a fraction of a second on something like that to overheat the apex and damage the steel.

[3D Anvil]

Adding the grinder to the equation certainly introduces the risk of overheating, but I doubt he did any damage with those two quick passes on a leather wheel.  It's also a variable speed grinder he's using.

[Ken S]

I would not be so quick to categorically write off an experienced sharpener using a variable speed higher speed grinder (buffer). I have watched Steve Bottorff, the most experienced knife sharpener I know, use a buffer with paper wheels. Another one of our highly respected members, the late Wootz (Vadim of Knife Grinders) has pioneered the use of felt wheels using higher speed buffers. Granted, these experts have the experience and skill to avoid pitfalls which might plague most of us.

I do not put myself in this high skill category; however, with much work and dedication, I believe most of us could reach that level.

Ken

EDIT: Here are two examples of using Tormek's with higher speed grinders:

https://tormek.com/en/products/accessories/bgm-100-bench-grinder-mounting-set

https://tormek.com/en/products/accessories/owc-1-tormek-converter

I have seen these mentioned in one of the online classes. I have not seen either actually used in these classes.

[Thy Will Be Done]

Adding the grinder to the equation certainly introduces the risk of overheating, but I doubt he did any damage with those two quick passes on a leather wheel.  It's also a variable speed grinder he's using.

You are certainly entitled to hold an opinion that it 'should be fine' but the reality is that the apex is so small (and most importantly has virtually no mass) that it can literally overheat in a fraction of a second and you would have no way of even detecting it.  In my view, combining this with a Tormek is rather silly considering the whole point is to guarantee the edge doesn't overheat.  You cannot do that with any non-cooled powered equipment, a guarantee, that is.  They cannot know and neither can you, period. 

[Ken S]

TWBD,

With all of my own sharpening, you and I are on the same page. I have a dry grinder that I purchased in 1973. I have not sharpened with it since purchasing my T7 in 2009. I also have two belt grinders converted to variable speed. These are useful for many things, although I do not sharpen with them.

I also have the parts for the BGM-100 and the other adaptor, although I have never installed either. Instead of going dry, I use a Norton 3X grinding wheel adapted for wet use with the Tormek. At 46 or 80 grit, they cut very fast. Used wet, they also cut coolly.

Ken

[3D Anvil]

Adding the grinder to the equation certainly introduces the risk of overheating, but I doubt he did any damage with those two quick passes on a leather wheel.  It's also a variable speed grinder he's using.

You are certainly entitled to hold an opinion that it 'should be fine' but the reality is that the apex is so small (and most importantly has virtually no mass) that it can literally overheat in a fraction of a second and you would have no way of even detecting it.  In my view, combining this with a Tormek is rather silly considering the whole point is to guarantee the edge doesn't overheat.  You cannot do that with any non-cooled powered equipment, a guarantee, that is.  They cannot know and neither can you, period. 

I share your concern, but my opinion wasn't formed out of thin air, but rather from a review of Vadim's extensive testing of edges and specific comparisons of blades sharpened on Tormek alone, versus in combination with paper and felt wheels on grinders, versus, only on grinders, etc.  This is also based on my own experience sharpening hundreds of knives -- mostly using Tormek to apex the blade, followed by honing on leather belts with various compounds.  In my experience, the leather belts, at the slowest speed of a Work Sharp Elite belt grinder, produce significantly less heat than paper wheels or felt on a half-speed grinder.  That said, I haven't tried a leather wheel on a grinder, so I can't speak to that specifically.

I think I'll do some side-by-side testing of my own, just for peace of mind.  Will report my results when I get them.

[Sir Amwell]

I would be very interested in any results 3D, as like you I hone on a WSKO blade grinding attachment at the lowest speed.let us know what you find.

[3D Anvil]

I surely will.  I ordered two identical 6" Victorinox kitchen knives this morning for the testing.  I'll probably start by sharpening each a few times just on the Tormek to eliminate any factory belt burn.

What do y'all think would be a good cut test?  Maybe slice up an equal number of carrots and take BESS readings to compare?  My wife, who's the cook in the house, suggests sweet potatoes. 

[Thy Will Be Done]

I surely will.  I ordered two identical 6" Victorinox kitchen knives this morning for the testing.  I'll probably start by sharpening each a few times just on the Tormek to eliminate any factory belt burn.

What do y'all think would be a good cut test?  Maybe slice up an equal number of carrots and take BESS readings to compare?  My wife, who's the cook in the house, suggests sweet potatoes. 

The difficult thing about testing edges is it's hard to know what exactly you are seeing is a result of how you sharpened it and not something else entirely.  Ideally you would introduce some sort of blinding as well, such as having your wife cut the materials and she has no idea which knife is which but you have a way of telling them apart.  Often what people report as large differences between knives/steels/etc are more a difference of some other factor such as random differences in sharpening, random differences in materials, etc.  You'd want to do a very large number of cuts with both knives across many runs to be confident in what you are seeing to some degree.

[Sir Amwell]

And there was me thinking you were going to go all Vadim on us with that coloured temperature sensitive whatjamecallit that he used in his heating tests. What we get is a carrot.
Tee hee!
Go for it 3D!

[Thy Will Be Done]

Even with temperature measuring equipment I'd still say you're unlikely to see evidence of overheating apex as it will cool off immediately once it's taken off the grinder/buffer, just as quickly as it overheated int he first place... in an instant.

[3D Anvil]

To me the issue with the temperature lacquers was that they were a millimeter or two back from the apex, where the area of concern is really the last 5-10 micrometers.  No way of knowing what the temperature gradient is in that critical area.  That's why I think the only practical way to test it out is to see how the edges perform in real-world use.

[tgbto]

I'm not sure what I think of these videos, but "perfectionist" might not be my first thought. The knife seems sharp all right, like 150 BESS max, but it had better be after 20 minutes of grinding... Why does he hone to check for a big defect, but then doesn't when the defect is supposed to be smaller? Marking the edge with a sharpie where the chip is would be faster if you want to put it under the microscope, but you can always check with a fingernail.

As for the honing on the high speed grinder - carrots and lacquers notwithstanding - the noise seems to indicate it is still fairly high speed, and the way he hones his knife will make quick work of whatever consistency he gained with the Tormek (one can see on the video that he doesn't hold the knife at the same angle on both sides, and also that his hand wobbles so the angle is not constant along the length of the knife). Did I miss something when he's talking 200 grit? I thought the coarsest diamond wheel was 360...

https://tormek.com/en/products/accessories/bgm-100-bench-grinder-mounting-set

https://tormek.com/en/products/accessories/owc-1-tormek-converter

Yup, none of which he is using on this video.

I use those on a high speed grinder when I want to quickly restore a much-abused chisel, I have not had to use them on a knife even when doing some heavy lifting, because a knife edge is so thin even the SG graded coarse reshapes them very quickly (it's even faster on a belt sander with a coarse belt).

And then I also use the BGM/OWC combination on my WorkSharp Blade Grinding Attachment, to hone on the leather belt for a few knives, but at a much, much lower speed than he does in the video.

[3D Anvil]

As far as the video goes, I think he could have saved himself a lot of time by just running the blade across his thumbnail to determine if all the chips had been removed.

I don't think you can guesstimate a BESS score from the paper test.