I found the technique and dedication used in this video outstanding.
https://youtu.be/XA4FR4Fq3K4
Ken
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.
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.
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.
Quote from: 3D Anvil on July 07, 2023, 06:43:22 PMAdding 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.
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
Quote from: Thy Will Be Done on July 09, 2023, 07:14:05 PMQuote from: 3D Anvil on July 07, 2023, 06:43:22 PMAdding 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.
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.
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.
Quote from: 3D Anvil on July 10, 2023, 07:24:54 PMI 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.
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!
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.
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.
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...
Quote from: Ken S on July 08, 2023, 04:37:39 AMhttps://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.
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.
Quote from: 3D Anvil on July 11, 2023, 04:35:37 PMI don't think you can guesstimate a BESS score from the paper test.
Well the idea was that there was no evidence of sub-60 BESS scores. And I stand corrected, according to Wootz' scale, paper slicing is 300 BESS and below.
So I did the test I mentioned earlier: two identical Victorinox 6" knives, both sharpened on Tormek. One was honed/stropped on a rock hard felt wheel, also on the Tormek. The other was honed/stropped on a Work Sharp Elite using leather belts, at the lowest available speed. In both cases, the first pass was at the sharpening angle +2° and the second pass was at the sharpening angle (15°).
After some hand stropping to equalize the results, both knives measured 105g on the BESS tester.
Test consisted of slicing up 5 carrots and 1 sweet potato per knife, on a wood cutting board.
Conclusion: no significant difference. The average of three BESS tests in the cutting area came out to 245 for one knife and 247 for the other.
I'm going to put it up on Youtube when I have a chance.
Interesting 3D.
So edge retention seems not to be compromised by the different honing methods.
So any potential over heating by using the WSKO leather belts seems not to affect the edge retention.
What is of interest to me is how quickly the sharpness decreases with these pretty standard kitchen tasks?
Yep, that was my conclusion. I don't think the leather belts create near enough heat to affect the temper of the edge.
As far as the change in BESS score goes, it didn't surprise me. These were at the low end of Victorinox's line, costing $21 each. They don't even state what the steel is, but it's probably 8cr4mov or something along those lines. Maybe 55-58 hrc? Also, the average factory edge comes in around 210 BESS, so the end result wasn't far off from that.
For what it's worth, here is the video of my honing edge retention test: https://youtu.be/A8xEQqrjbDM
Loved the video 3D. Make more!
As an aside, as commented earlier on about the drop in sharpness after the the test slicing/ chopping which I found surprising. I think that using your knife to push sliced food away across the chopping board by scraping with the knifes edge seriously dulls the edge. It doesn't affect the validity of your results as you did pretty much the same with both knives.
I always tell my customers not to use the knife edge to push/scrape the food away on the board.
Get into the habit of using the spine of the knife to do this. Retention will be much better.
Thanks, man! The irony is that I'm always on my wife not to drag the blade sideways across the cutting board. However! If you pay attention, you'll see that (I think) I only used the blade side that way one time. Otherwise, I'm using the spine-side of the blade to collect the cut food.
In order to preserve the domestic harmony, integrity of the kitchen knives, and the fingers, I recommend keeping one of these dough scrapers by the cutting board.
https://www.amazon.com/Ourokhome-Stainless-Dishwasher-Laser-Engraved-Conversion/dp/B09G5ZJTZW/ref=sxin_14_pa_sp_search_thematic_sspa?content-id=amzn1.sym.1c86ab1a-a73c-4131-85f1-15bd92ae152d%3Aamzn1.sym.1c86ab1a-a73c-4131-85f1-15bd92ae152d&crid=11WFJ5RRGHG6A&cv_ct_cx=pastry%2Bcutter&keywords=pastry%2Bcutter&pd_rd_i=B09G5ZJTZW&pd_rd_r=14f39405-a6b5-4430-96fe-740806bc6141&pd_rd_w=bJger&pd_rd_wg=FidMQ&pf_rd_p=1c86ab1a-a73c-4131-85f1-15bd92ae152d&pf_rd_r=KXJCS88R1T09HSZQ2RY1&qid=1689566310&sbo=RZvfv%2F%2FHxDF%2BO5021pAnSA%3D%3D&sprefix=Pastry%2B%2Caps%2C180&sr=1-3-364cf978-ce2a-480a-9bb0-bdb96faa0f61-spons&sp_csd=d2lkZ2V0TmFtZT1zcF9zZWFyY2hfdGhlbWF0aWM&th=1
Ken
Quote from: 3D Anvil on July 15, 2023, 05:58:47 AMYep, that was my conclusion. I don't think the leather belts create near enough heat to affect the temper of the edge.
My two cents : I sometimes hone on the WS Elite/BGA with the leather belt, and I don't expect much heat production that way. In the video by the OP however, the speed seems much higher (and the high-volume high-pitch sound produced seems to back this up).
Quote from: tgbto on July 17, 2023, 08:51:28 AMQuote from: 3D Anvil on July 15, 2023, 05:58:47 AMYep, that was my conclusion. I don't think the leather belts create near enough heat to affect the temper of the edge.
My two cents : I sometimes hone on the WS Elite/BGA with the leather belt, and I don't expect much heat production that way. In the video by the OP however, the speed seems much higher (and the high-volume high-pitch sound produced seems to back this up).
I agree. The leather wheel he's using sounds a lot like a paper wheel on the grinder, and I find that paper wheels introduce a lot more heat than leather belts, even with my 1/2 speed grinder.
From what I can see on the video, it looks like he's using a wheel made with stacked leather discs, and the honing is done with the side of those discs. So yeah, I think friction is much higher than on a Tormek with the smooth leather wheel.
Lots of assumptions about the speed of that leather disc wheel have been made here.
The RPM control at the machine seems to be set to a low RPM.
I could not find any information about the actual RPM in that video.
So, I do not know if it runs fast.
Quote from: HaioPaio on July 21, 2023, 12:50:23 PMLots of assumptions about the speed of that leather disc wheel have been made here.
The RPM control at the machine seems to be set to a low RPM.
I could not find any information about the actual RPM in that video.
So, I do not know if it runs fast.
Well, here's the grinder (https://www.amazon.com/Shop-Fox-W1839-Variable-Speed-Grinder/dp/B01M1A4XD0?th=1) (a Shop Fox W1839 that it says runs from 2000-3400 rpm), that he's apparently running in the middle of the range based on this (https://youtu.be/R0DhQOt62c0?t=114).
::)
Quote from: cbwx34 on July 21, 2023, 03:27:21 PMQuote from: HaioPaio on July 21, 2023, 12:50:23 PMLots of assumptions about the speed of that leather disc wheel have been made here.
The RPM control at the machine seems to be set to a low RPM.
I could not find any information about the actual RPM in that video.
So, I do not know if it runs fast.
Well, here's the grinder (https://www.amazon.com/Shop-Fox-W1839-Variable-Speed-Grinder/dp/B01M1A4XD0?th=1) (a Shop Fox W1839 that it says runs from 2000-3400 rpm), that he's apparently running in the middle of the range based on this (https://youtu.be/R0DhQOt62c0?t=114).
::)
You also have to consider that it's a 6" wheel, so it will be considerably slower (feet per second) than an 8" or 10" wheel rotating at the same speed.
When I posted the link to this video, I did not anticipate the amount of attention using a higher speed buffer would receive. I have never owned or used a buffer. I also have not used my dry grinder in a dozen years.
Discounting the higher speed buffer, I still believe the video has value. I was impressed with the more in depth understanding of paper tests he demonstrated. He also demonstrated a practical efficient command of using his digital microscope.
Ken
Quote from: HaioPaio on July 21, 2023, 12:50:23 PMSo, I do not know if it runs fast.
The relative intensity as well as pitch/frequency of the sound of the blade on the wheel is quite telling though, even if it is not a tachometer.
Quote from: 3D Anvil on July 21, 2023, 05:17:03 PMYou also have to consider that it's a 6" wheel, so it will be considerably slower (feet per second) than an 8" or 10" wheel rotating at the same speed.
A T-4 honing wheel rotates at 120RPM, for a diameter of 5 3/4". So even if he were using it at 2000 RPM, that is still 17 times faster. Or 15.5 times faster than the T-8 with LA-220.
Thanks for clarifying. We know now that this machine runs between 2000 and 3400 RPM.
Vadim Kraichuk did an fairly comprehensive testing on overheating of the knife apex. The report is available here http://knifegrinders.com.au/SET/Heat_in_Sharpening.pdf
Unfortunately, he did not directly address this type of leather disk wheel.
For general buffer wheel materials he concluded at page 19, that no overheating occurs, even with full speed.
Vadim most likely operated his machines in a 50 Hz environment.
So, his machines ran at 83% of the speed in an 60 Hz net.
Does anybody know facts about leather disc buffers?
Has anybody hands on experience with it?
I read in an ad that the leathers discs would not be glued together at the outer area and the air between the discs would support cooling. https://prosharpeningsupply.com/collections/wheels/products/leather-honing-wheel-fits-6-in-bench-grinders-and-polishers
The unglued space between the layers of leather allow for airflow and result in a much cooler running wheel, meaning you can make more passes in less time without overheating the blade.
I do not know if this is true.
Quote from: Ken S on July 21, 2023, 05:25:38 PMWhen I posted the link to this video, I did not anticipate the amount of attention using a higher speed buffer would receive. I have never owned or used a buffer. I also have not used my dry grinder in a dozen years.
Discounting the higher speed buffer, I still believe the video has value. I was impressed with the more in depth understanding of paper tests he demonstrated. He also demonstrated a practical efficient command of using his digital microscope.
Ken
I was more impressed with the microscope than anything he was doing, not to say he was unskilled but nothing struck me as being unique about his abilities. Discriminating, yes. Outstanding? I suppose many commercial sharpening outfits are not this thorough but I definitely will not let blades leave that are not dialed in when it comes to my business.
It seems that this thread is now becoming polarised into whether the you tuber that initiated the discussion is correct in his chosen honing technique.
The technique he used maybe open to debate among purist Tormek users. Is it too fast and overheating the edge? Etc etc.
The process obviously works for him.
More pertinently, does it work for his customers?
Us Tormek users, slow and steadily and opinonatedly pursuing some holy grail of an ever decreasing Bess score, believing our way is the only way.
I get it. I've done it.
In the real world though away from our safe, organised and territorial workshops, customers want sharp knives. Do they care if it's 120 or 46 Bess? Do they care how their knife has been sharpened as long as it's satisfactorily sharp AND stays sharp for as long as possible ( good edge retention)?
I hope not to invite approbation from the belt grinding community. We know that using this method is highly likely to compromise the temper on the edge of a knife, even with frequent dunking in water to cool the edge ( arguably the damage is done before the chance to cool).
And us Tormek users can get very snobby about this, yes?
But the proof is in the slicing.
I personally prefer quality over quantity and like to know I have not compromised a customer's knife.
And so it then becomes easy to judge others.
What counts is edge retention.
Thanks to 3D for his work on this.it's reassuring.
What will be reassuring to the sharpener, the original subject of this topic, is whether his customer is happy and doesn't come back after a week saying 'it was really sharp and now it's already blunt' , or simply not use his services again.
His protocols will adjust accordingly.
Just my long winded twopennorth worth.....
To be precise I have not wandered into the overheating or not realm.
My concern is rather how an uncontrolled honing on a high speed device may change the apex angle in an uncontrolled fashion, especially seeing how the wrist angle varies in the video. And whether cutting paper the way the sharpener did is any indication of an outstanding outcome of the sharpening process.
Wrt edge retention, the sweet potato test indicates that there is no significant difference between the two knives, but my opinion is the angle was more controlled throughout the process and the speed of the honing way lower.
Good comments, deserving of better explanation. For several years I have regularly watch sharpening videos to expand my knowledge. I try to glean ideas. Not all of these videos are Tormek specific. If I see an interesting technique using another method which I feel can benefit my Tormek technique, I incorporate it into my knowledge base. I also tend to pass over or ignore things which do not seem to apply to or benefit my needs.
While working on this reply, I watched this video again. I am still impressed with Paul's use of the microscope. This is certainly not original; however, it is well demonstrated. I admit that I did not pay much attention to the honing portion. I have never used a buffer, being quite content with the Tormek leather wheel used at low speed. I sharpen for my own needs and do not feel any need for speed.
Ken