which steel gets sharper

[john lucas]

I finally finished this article and got it published in the latest issue of More Woodturning. thought you all might find it interesting.
https://www.morewoodturningmagazine.com/articles.php?articlesid=112&access=7e7d78763e40

 

[hockenbery]

Terrific article.
It is obvious you put a lot of hours into this.

Thank You!

 

[Mark Hepburn]

John,

I enjoyed your article, and you sold a subscription too.

 

[odie]

John.....nice work!

It is surprising that the BESS tester showed a direct conflict with the photo results. Did you do the test with the same pieces of steels that were shown in the photos? OK, given the conclusions you've reached (7 grams overall difference), what is your expectations the practical difference will be to a turner? I suspect the answer to that question will be minimal, if any......but am interested in your observations, conclusions.

It seeems to me that Sharpness is only relevant subject to many other things.....such as rpm, correct presentation, and so forth......

-----odie-----

 

[john lucas]

Odie I did use the same pieces of steel to do the BESS test. As I mentioned the 7 grams of difference is extremely small. The same with the photos at 5000X magnification. Up to 1000 times we still couldn't see any difference in sharpness. At 2500X it just started to show. So for all practical purposes they were equally as sharp. What was fun was finding out how sharp they were in comparison to other sharp things like kitchen knives and razor blades. Most what I was trying to prove or disprove was that one steel would get sharpen than another. For our purposes and the tools we use I would say no, they are equal. No that is assuming of course that it's decent steel that has been properly heat treated. We all have had instances of crappy steel that simply won't get sharp. I tried to sharpen a cheap pocket knife for my son the other day and it simply would not get sharp. Without magnification I couldn't tell you why but it would barely shave hair and would drag when cutting paper. Even cheap paring knives will get sharper than that easily. The tools I sharpened for this test would cut paper like it was hardly there and of course would shave hair easily.

 

[Jon Minerich]

John,
I am still learning how to properly sharpen my tools, so I may be confused. After reading your article on sharpening, I think
I understand that any good quality HSS tool will perform well. That being the case, did the tool manufacturers develop new steels just to hold a sharp edge longer? All my tools are HSS so I don’t have anything for comparison.j
Thanks,
Jon

 

[john lucas]

Wow been a long time since I've been to Biloxi. Was in the Air Force there in 68 and 69. Left just days before Hurricane Andrew hit. Yes tool manufacturers have been trying to find ways to make the edge last longer. First of course was simply hardening correctly. Too hard and then edge chips. Not hard enough and the edge wears away too fast. then came Cryogenic treatment. Basically freezing the steel which helps more of the particles of metal that are changed by heat treating to also change thereby having a more even structure to the metal. With HSS or other steels that are melted to form the tool you can only get so much Vanadium in the steel. 4% if I remember corrrectly. With the particle metal steel like the Thompsons you up to 15% but that gets really expensive so Doug Thompson chose 11% (or maybe 10 can't remember). the Vanadium ads wear resistance and toughness to the edge. His tools are also Cryogenically treated to further enhance the edge holding. I don't know the composition of M42 (looked it up but forgot) but it also holds an edge for a very long time. It used to be that the harder steels and carbides simply would not hold an edge. The edge chipped too easily. Consequently when you tried to sharpen them to a really keen edge the edge simply chipped. That is why Carbon Steel was the preferred steel for carving knives and other tools needing a really fine edge. With modern steel treatment this changed and that is why I wanted to do this test. To see for myself if the modern steels could be sharpened as sharp as High Carbon Steel. they can as shown in my tests. Now edge holding tests are far more involved and I simply don't have the equipment, time or money to do that test. It would require cutting a known amount of material at a fixed depth of cut for fixed period of time and do this hundreds of times with several samples of each steel. There might even be more variables. I did find out in my own rough experiments that sharpening an edge to a finer grit improved edge holding. I did this with 2 tools. I turned a bunch of Hand mirror handles and over several days sharpened each tool many times using 2 different grits. I observed the shavings coming off the tool and when they quit being long and beautiful I would resharpen using the other grit. After 3 or 4 days of this it was pretty obvious even with all the variables that the tools sharpened on the 320 grit held a sharp edge longer than the tool sharpened at 180. this was done with a wide variety of woods. Now I can't say how long that tool would have cut with a less than sharp edge. Again, too many variables.

 

[Jon Minerich]

Thanks for the explanation. I will try a finer grit for sharpenening and see what happens.

By the way, You probably wouldn’t recognize Biloxi. After Katrina, they rebuilt a lot of Gulfport/Biloxi. We just moved down here for my planned retirement 1 1/2 years ago. and we like it a lot. (I just formally retired a few days ago-Jan 2nd). So we are here to stay. The Lighthouse Woodturners is a great bunch of guys and they are very generous with their time and resources helping newbies like me.

 

[john lucas]

I drove through Biloxi really fast about 2 years ago coming back from Texas. Wanted to stay and look at all the changes but didn't time. You could tell a lot changed. My room mate at the time was still in Biloxi when the storm hit. He took a lot of photos and sent them to me. There were huge ships 1/2 mile inland some sitting on a golf course.

 

[odie]

As long as we,ve touched on the subject of edge holding ability, I have a comment about that. I believe most turners almost universally feel that the ability to hold an edge longer is the most desirable. While I did feel that way at one time, I,ve come to alter my opinion about that. The reason I feel that way is I will spend less time debating the the issue.....because there is little difference between "almost sharp" and "almost dull". I find that my tools will be sharper over time if they dull a little quicker, because I spend less time making the decision to re-sharpen. my tools will spend less time in that zone where a decision must be made.

It is my opinion that good quality M2 steel will allow me to be a better turner than if my preferred tools held an edge for a longer cycle between sharpenings. This, of course, requires me to sharpen more often, but I feel the inherent advantage is well worth it !

-----odie-----

 

[Gerald Lawrence]

I agree with you Odie. I got some CBN Cards from Ken and honing with them really makes a difference cards are double sided and go up to 600. Never got that good of a result with diamond hones.

 

[odie]

I agree with you Odie. I got some CBN Cards from Ken and honing with them really makes a difference cards are double sided and go up to 600. Never got that good of a result with diamond hones.

hi Gerald.....

In my experience, the diamond hones work great for awhile, but they do wear out after a few months. The life span can be increased somewhat by limiting the pressure while honing. The diamond dust doesn,t wear out, but the adhesion process used isn,t great. I,m currently using some cheap Chinese made ones available online.....less than $5 apiece, so they can be considered disposable.

If you wouldn't mind, give me a link to the CBN hones you speak of, ok? Thanks.

-----odie-----

 

[john lucas]

I used to use the plastic diamond hones like EZLap and the other brand. They wear out quickly. I spent the big bucks on a TRend double sided diamond hone and it's still working fine after 2 years. I do apply a little of the trend lapping fluid occasionally which seems to make a difference.
As far as the using lesser steel so the tool gets dull faster I just can't hang onto that. I try not to let my tools get dull. I sharpen a lot. To me it just makes more sense to use good steel that will hold an edge. I hate sanding tearout so as long as I can see good shaving coming off the tool I'm good to go. Once they don't seem that good, well I've waited too long and should have sharpened a few minutes ago. I know we will have to agree to disagree on this on Odie.

 

[Gerald Lawrence]

hi Gerald.....

In my experience, the diamond hones work great for awhile, but they do wear out after a few months. The life span can be increased somewhat by limiting the pressure while honing. The diamond dust doesn,t wear out, but the adhesion process used isn,t great. I,m currently using some cheap Chinese made ones available online.....less than $5 apiece, so they can be considered disposable.

If you wouldn't mind, give me a link to the CBN hones you speak of, ok? Thanks.

-----odie-----

https://woodturnerswonders.com/collections/unique-tools/products/credit-card-hone-new Try this and look around Ken has some good stuff even CBN wheels for under 100.

 

[Hy Tran]

I finally finished this article and got it published in the latest issue of More Woodturning. thought you all might find it interesting.
https://www.morewoodturningmagazine.com/articles.php?articlesid=112&access=7e7d78763e40

John,

Awesome article, thank you. The one question I have that isn't clear is, what is the measurement uncertainty with the BESS system? 7 grams is insignificant in magnitude when you compare, say, razor to kitchen knife--but what are the statistical and non-statistical (lay folks might call them systematic) errors in measurement? I accept your conclusions regardless of the measurement uncertainty, by the way

Best wishes,

Hy

 

[john lucas]

I can't answer that. I'm very new to the BESS machine and it was borrowed. I have been to their website and a lot of knowledgeable people there on the forum. All I know is when I ran the blades through 3 times I got virtually the exact same reading +/- 1 so the readings are very consistent. You can change the reading a little by tilting the blade so it is slicing rather than pushing through the medium. I tried very hard to maintain the same angle of cut when testing.

 

[robo hippy]

I had an old set of DMT diamond plates that I had stopped using but couldn't throw away. On a whim, I applies some of the Trend Lapping fluid on them. They almost cut like new again. Just plain water doesn't work....

robo hippy

 

[Hy Tran]

I can't answer that. I'm very new to the BESS machine and it was borrowed. I have been to their website and a lot of knowledgeable people there on the forum. All I know is when I ran the blades through 3 times I got virtually the exact same reading +/- 1 so the readings are very consistent. You can change the reading a little by tilting the blade so it is slicing rather than pushing through the medium. I tried very hard to maintain the same angle of cut when testing.

Thank you, you've demonstrated +/-1 gram repeatability. The 7 gram difference is likely some real difference in cutting force, but as you say, insignificant in the greater scheme of things.

Best,

Hy

 

[john lucas]

When you consider that the double edge razor read 60 and single edge razor read 100 and the utility razor read 200. My tools all read around 170 with the one tool measuring 177. We are really splitting hairs. I stropped the utility razor and got it down to 130. When you consider that the sharpening angle on the razors was less than my tools you can understand why they get lower readings. Compare the 170 with all of my Kitchen knives that will shave hair and read closer to 300 you get to see how small 7 points is on that scale.