Why are burrs so malleable?

[EOU]

No one is going to cry over a few sliced onions Me2...or, maybe they will. Do you feel that there is the possibility that fewer iron oxides/sulfides might be raised to the surface using one abrasive as opposed to another? Our understanding of the passivation process is that it serves to remove these impurities thereby inhibiting corrosion. Interestingly enough, we understand that citric acid is often a component of this passivation process. This is an interesting discussion and particularly so because of the abundance of stainless steel edges in use today. Thanks for bringing this up Me2. It may be a far more important and prevalent problem than most realize.

[me2]

Funny you mention that. These onions are particularly strong. Normally I don't have issues cutting up even 2 full onions, but these I had to step outside to clear my eyes after just 1/2 of the first one.

I limited this issue to carbon steel blades, as I've not noticed it in the stainless blades I've tested. I normally sharpen the Bunka on water stones, but this time used the Sharpmaker for convenience. I haven't noticed excessive corrosion in the past, so that led to the question of whether sharpening method makes a difference. The 4k stone finish is more polished than the Sharmaker medium finish it had this time, which could make a difference, though I doubt it'd be significant on it's own. As noted above, these onions were particularly strong, which could be a factor as well.

My sharpness testing set up is not standardized, and so won't be translatable to the BESS scales, however it allows for detailed relative comparisons for knives on hand. I'll have to drag it back out to explore this further. IIRC, double edge razor blades are around 10 grams to cut the thread I'm using, while carefully sharpened knives start at around 15 off the standard fine white stones of the Sharpmaker or my best efforts with the 4k stone. I have some 1 micron and 0.3 micron honing films, but my supply is limited, and I'm reluctant to use them for normal sharpening. This might be the time to start.

[EOU]

The numbers you generated are good enough for us Me2 and very helpful. Your numbers are somewhat translatable in our opinion thanks to the very predictable sharpness level of DE razor blades. You don't have to own an edge sharpness tester to relate to the BESS. We'd say your 10 is 50 on the BESS C and your 15, theoretically, is around 75 or so.  Now we have a good idea of where you are at and where you are at is sharp! We look forward to more from you on this as you continue your experiments.

[Ken S]

I took advantage of some middle of the night insomnia quiet to slowly read this topic. Several thoughts came to mind:

For the past eight years, I have sharpened primarily with a slow speed water cooled Tormek. Recently I have worked on converting a Viel and Kally 1SM belt grinders to variable speed. With surface feet per minute equaling the circumference of the drive pulley (D x pi) times RPM, I lowered the RPM of the Viel by about a third by switching to a four inch drive pulley similar to the 1SM pulley. The standard Viel drive pulley is six inches. The variable speed DC motor has a range somewhere around 700 RPM to an amount higher than 1725 RPM. I rarely use anything except the lower range. This speed is still above Mark's "speed of smell". Mark, I know you recently acquired a Gen III Viel, with smaller drive pulley and variable speed motor. Do you notice any difference between edge burr from your full speed Kally and the slower speed Gen III? What about with your Tormek? My question here is could there be a correlation with heat generated by higher speed grinding?

I did some testing with CBN wheels on a Tormek, used wet or dry. The wheels I used were steel D-Way with steel reducing bushings. I used Hone Rite Gold with the water to prevent rust. After reading about corrosion, I am wondering if routine use of Hone Rite Gold might be a good practice with either the Tormek or with water stones. I just watched a video with Rob Cosman using Hone Right Gold. I had not noticed him using it in earlier videos.

My third burr thought was with hand scrapers. When I was in my twenties, I met an elderly refinisher. He was a genuine expert who had apprenticed with an old Austro Hungarian cabinetmaker. He and his teacher were great believers in the hand scraper. Here, instead of trying to remove the burr, we use the burr to enhance scraping. The burrs (double) are formed by pressure, rolling a hardened rod over the edge. In skilled hands, the burrs can be quite large. When the burrs are longer usable, the scraper edge is ground away, back to "good", non fatigued steel.

I generally sharpen knives with the edge trailing. The factory configuration for the Tormek square edge jig for chisels and plane irons is grinding into the edge. Do those of you who sharpen with a belt grinder sharpen into or trailing the edge?

Ken

This is a fascinating topic.

[Rupert Lucius]

I took advantage of some middle of the night insomnia quiet to slowly read this topic. Several thoughts came to mind:

For the past eight years, I have sharpened primarily with a slow speed water cooled Tormek. Recently I have worked on converting a Viel and Kally 1SM belt grinders to variable speed. With surface feet per minute equaling the circumference of the drive pulley (D x pi) times RPM, I lowered the RPM of the Viel by about a third by switching to a four inch drive pulley similar to the 1SM pulley. The standard Viel drive pulley is six inches. The variable speed DC motor has a range somewhere around 700 RPM to an amount higher than 1725 RPM. I rarely use anything except the lower range. This speed is still above Mark's "speed of smell". Mark, I know you recently acquired a Gen III Viel, with smaller drive pulley and variable speed motor. Do you notice any difference between edge burr from your full speed Kally and the slower speed Gen III? What about with your Tormek? My question here is could there be a correlation with heat generated by higher speed grinding?

I did some testing with CBN wheels on a Tormek, used wet or dry. The wheels I used were steel D-Way with steel reducing bushings. I used Hone Rite Gold with the water to prevent rust. After reading about corrosion, I am wondering if routine use of Hone Rite Gold might be a good practice with either the Tormek or with water stones. I just watched a video with Rob Cosman using Hone Right Gold. I had not noticed him using it in earlier videos.

My third burr thought was with hand scrapers. When I was in my twenties, I met an elderly refinisher. He was a genuine expert who had apprenticed with an old Austro Hungarian cabinetmaker. He and his teacher were great believers in the hand scraper. Here, instead of trying to remove the burr, we use the burr to enhance scraping. The burrs (double) are formed by pressure, rolling a hardened rod over the edge. In skilled hands, the burrs can be quite large. When the burrs are longer usable, the scraper edge is ground away, back to "good", non fatigued steel.

I generally sharpen knives with the edge trailing. The factory configuration for the Tormek square edge jig for chisels and plane irons is grinding into the edge. Do those of you who sharpen with a belt grinder sharpen into or trailing the edge?

Ken

This is a fascinating topic.

Merry Christmas to all that have participated and also you lurkers (please make the decision and come aboard and participate).

Most of the time I am sharpening into the edge.

Maybe it is more a mood thing - I, do not know - for sure there is less burr when going into the edge.

Rupert

[Mark Reich]

Mark, I know you recently acquired a Gen III Viel, with smaller drive pulley and variable speed motor. Do you notice any difference between edge burr from your full speed Kally and the slower speed Gen III? What about with your Tormek? My question here is could there be a correlation with heat generated by higher speed grinding?

I've only used my Gen III with a leather belt and 16µ PDP compound for burr removal and fast touchups. This is a very aggressive compound at only 1000 grit. With the sharpest particles, this is the toothiest compound that stays on a leather belt. It's easy to create a burr on a Kally, especially when it's freshly loaded, but easy to manage on the Gen III or leather hone.

I only use my Tormek for hair scissors, with a wet 4K wheel. I should use it more, but I've been sharpening woodworking tools on an industrial bench grinder all my life so that's what I'm used to. I'm very aware of the heat, and use a dip bucket.

Belt or wheel speed can be a factor when you're trying to minimize the burr, normally when finishing. Pressure and Grit have everything to do with heat. When necessary, dipping in water is an unconscious act, otherwise I'd be burning my fingers constantly. 

I did some testing with CBN wheels on a Tormek, used wet or dry. The wheels I used were steel D-Way with steel reducing bushings. I used Hone Rite Gold with the water to prevent rust. After reading about corrosion, I am wondering if routine use of Hone Rite Gold might be a good practice with either the Tormek or with water stones. I just watched a video with Rob Cosman using Hone Right Gold. I had not noticed him using it in earlier videos.

I very rarely worry about oxidation, never corrosion. I'm used to wiping stuff clean and pretty dry when necessary. 

My third burr thought was with hand scrapers. When I was in my twenties, I met an elderly refinisher. He was a genuine expert who had apprenticed with an old Austro Hungarian cabinetmaker. He and his teacher were great believers in the hand scraper. Here, instead of trying to remove the burr, we use the burr to enhance scraping. The burrs (double) are formed by pressure, rolling a hardened rod over the edge. In skilled hands, the burrs can be quite large. When the burrs are longer usable, the scraper edge is ground away, back to "good", non fatigued steel.

I like using scrapers with a burnishing tool. The work hardened hook lasts longer. I use a regular burr from sharpening the hook end of these Way more often. I have many, because they are super handy, useful and inexpensive.

I generally sharpen knives with the edge trailing. The factory configuration for the Tormek square edge jig for chisels and plane irons is grinding into the edge. Do those of you who sharpen with a belt grinder sharpen into or trailing the edge?

Almost always edge trailing with belt grinders, almost always edge leading on hard surfaces, like grinding wheels or stones.

Mr Grepper, can you move this last post by Mr Ken and these replies into a new thread, Please? This thread has meandered too far, and "Why are burrs so Malleable" is a topic worth it's own thread IMHO. 

[Ken S]

I agree with Mr. Mark's request for these posts. Good thought, Mark.

Ken

[Ken S]

Please see my topic in forum assistance.

Ken

[grepper]

Sorry for the delay in responding.  I've been out of town due to the holidaze.

I'm more than happy to assist in any way I can!
 
Mr. Mark, What thread would you like Mr. Ken's post an your reply moved to?  If the thread does not exist, please create it and let me know.  I'll move the posts.  I'm not sure what you wish to call the thread, or if you wish it moved to some other existing thread.

I fully agree with your and Mr. Ken's suggestion that we try to create new subjects instead of letting threads meander endlessly.  It's really easy to create a new thread, and, as Mr. Ken mentioned there is a lot of great information here. Distinct posts and better organization will improve the Exchange for the benefit of everyone. 

I agree that these posts deserve a thread of their own.

[Mark Reich]

Excellent! It is Great to know it's not hard to break a thread into separate subjects, because it's so common to have a thread make sharp turn.

I realize that most of the time these sudden digressions are not intended to break away from the original topic, and it's just for some simple clarification.

Other times, a great question can totally change the course of a thread. That's when it becomes problematic for me to find the new subject, hidden within an unrelated topic.

IMHO, that's why searches become useless on other forums. If can manage to nip this in the bud, and make it easy to snip a topic into a new thread, maybe we can avoid this pitfall.

At the same time, I fully realize a couple things- First, it's probably the "moderator's" job, and second, we can't get trigger happy on making that kind of decision.

Also, I totally understand that it's difficult to impossible to realize when a simple question will lead to a change of direction. It's totally normal to ask a pretty relevant question without starting a new thread so this won't be easy, but I believe it will make a unique, easily digestible forum. I'm asking for help in making these decisions.

Thank you, Gentlemen!