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Tool Edge Micrographs

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So, I "borrowed" a microscope from work (they'll never miss it).

Took an inexpoensive HSS SRG, and sharpened in various ways. Here are the micrographs:

Dry grinder, 80 grit CBN wheel: 80 Grit CBN-r25.jpg
Dry grinder 180 grit CBN wheels: 180 Grit CBN-r25.jpg
Tormek immediately after leveling stone (no grading): Tormek Fresh Stone-r25.jpg
Tormek after rough grading and honing the flute: Tormek Rough Graded Honed Flute-r25.jpg
Tormek after fine grading and honing the flute: Tormek Fine Graded Honed Flute-r25.jpg No, I did NOT switch these photos. Weird huh?

More photos in next post. I hit the 5 photo maximum.
 
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Here are the photos with my new 280 grit Tormek CBN wheel:

Tormek CBN Honed Flute-r25.jpg

and here is a blue light photo to show the edge detail:
Tormek CBN Edge Detail-r25.jpg

I expected the CBN wheel to be a bit rough when I first started using it. Based upon my experiences with CBN wheels on the dry grinder, it seems like there is a several month break-in period, during which the CBN grades up quite a bit.

So, what do you think? Cool photos huh?
Still have the microscope. Any request photos?
Sorry, I cannot do AO wheels, I no longer own any.
 

hockenbery

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Jeff,
Cool photos!
The tormek get closest to what I would call a razor blade edge.
The edge I would want for hand carving.

The question is what do they mean with regard to woodturning?
I have heard several experts say the seratted edge from a 60 grit wheel cuts wood really well.
Suggesting the CBN 80 would be best with regards to serrated edge.
 
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When looking at the first set of pictures from the CBN wheels, I thought they looked pretty rough, and I was wondering how 'new' they were. They do smooth out a LOT as they break in. Probably the same with your 280 grit wheel. Break in depends on how much you use them.

robo hippy
 
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interesting

Jeff,

Any chance of getting a picture of a new shaving or medical grade razor blade and/or a razor knife blade? Just curious how they compare to these images.

Were those first images deburred or were we looking at the burr?

Trying to figure out what we are seeing. Very interesting regardless and your time and effort are much appreciated!

Hu
 
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just a thought how bout a pic of a new razor blade
or a shave the hair of your arm sharp knife
just for comparison;)

hu beat me to the post button
 
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odie

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Interesting photos, Jeff.....and, thanks for investing the effort in showing us.


Question: With the honed edges, are you just taking off the burr from inside the flute, or are you honing both sides? I'm one who hones both sides, and there is a noticeable secondary bevel on the edge of the grind, with the first honing. The secondary bevel increases in size with subsequent rehonings, until a regrind is necessary.

ooc
 
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john lucas

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Thanks for the photos Jeff. What magnification did you use so I might have some comparison if i ever get my project done.
I spent quite a while sharpening my newer carving tools on the tormek and I don't feel they are as sharp as using some of my ceramic stones. I feel there is a gap between the grit of the stone graded fine and the polishing with the green compound on the strop. When I sharpen using the ceramic stone it seems to polish the steel better than the tormek stone. I do polish the tools after the ceramic on the green compound strop on the tormek. Of course I've never been able to see the edge magnified over 20 times but there is a noticeable less striation on the ceramic stone vs the Tormek.
 

Bill Boehme

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John, there are now several stones available for the Tormek. You might want to look at their ceramic stone for carving tools. Honing on the Tormek is something that, if not done correctly, will ruin a good edge. Many Tormek user get obsessed with putting a mirror finish on bevels -- It can be done --- at the expense of a sharp edge. The proper way to hone is to just remove the wire edge which means feather light pressure and just a couple seconds of honing. The bevel should have a smooth gray color and not be polish to a mirror finish.

They also have a black stone for shaping tools.
 
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Thanks for the comments all. I posted those first set of photos quickly, because I promised and wanted to get the thread going. This weekend, I will spend some more time to provide better and more photos. I will include those sharpened using my Sorby EdgePro (belt sharpener), and will include some fresh scalpel blad pix for comparison. I will also attempt to photo the edges head-on to show the burr, if there is one. It is a bit tricky, as I have to adjust the depth of field and focus just right. The digital output loses some quality over binocular vision through the eyepieces.

This is 200 times magnification. I have capability to use white and near UV blue light to light the subject matter.
 

Bill Boehme

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Jeff, when I sharpen a skew on my Tormek after the edge is sharp, I flip the tool from one side to the other using progressively lighter pressure to try to prevent any roll over at the edge. As a last step, I lightly hone both edges for a second or two on each side -- but it does take a few seconds to get the angle set just right on the honing wheel to make sure that I am not honing away the edge, which can easily happen. I use a Sharpie to paint the bevel to facilitate fine tuning the jig setting. Most of my skews have a 35° included angle.
 
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Thanks Bill. I do something like that as well, but didn't want to "muddy the waters" on these initial photos. I did not hone the cutting edge, just the flute side. I wanted to knock off any burr, so that the edge itself could be seen more clearly. This weekend, I'll do a more thorough set of photos, including honed edges.

My CBN wheels are rather new and, perhaps haven't settled down yet. When moving the shop from up north, my grinder was dropped, damaging both my original, and already broken in wheels. These are the replacements. They are only about a month or two old. I tried using the damaged CBN wheels for some time, but got too annoyed at avoiding the scars to continue that way any longer.
 

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The term "200 times magnification" is meaningless here, because we have no way to account for the scale factor of the camera, the effects of reducing file size for transmission and the characteristics of the display. Do you have any way to determine the actual dimensions of the individual pictures? An interesting experiment, nevertheless!

Dennis
 

john lucas

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I was wanting to know what magnification he used so when I do my tests I can use something similar so we have some sort of comparison. I realize we don't have a standard but we have to start somewhere.
 

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The term "200 times magnification" is meaningless here, because we have no way to account for the scale factor of the camera, the effects of reducing file size for transmission and the characteristics of the display. Do you have any way to determine the actual dimensions of the individual pictures? An interesting experiment, nevertheless!

Dennis

It will be different for every monitor. Some monitors have a resolution in the neighborhood of 70 pixels per inch while others might be 110 pixels per inch. However the scale factor from the camera, resizing software, and monitor basically have no effect on the structure revealed by the microscope itself. It may look larger or smaller than what is seen by looking directly through the microscope, but the size effects of everything downstream of the microscope doesn't add any further detail to the image. The thing that is most important is that all of the images were made at the same magnification so that we can compare apples to apples without the need to know precisely what an inch on your screen translates to on the actual object. It is a comparative study so that we can see the resulting edge from different kinds of sharpening tools. If a millimeter would fit in the picture, that might give you an idea of what 200X magnification means, but it doesn't otherwise add anything. We had a scanning electron microscope at work and we often looked at magnifications of 50,000X. The fact that an inch would be almost a mile was far more abstract than simply using the photomicrograph for its intended purpose of performing failure analyses.
 
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I almost didn't want to answer that question about magnification, because I KNEW it was very relative to a variety of things.

When taking the photos, I used the "200x" objective lens. In this type of microscope, the actual magnification is dependent upon several factors, including focus and distance of object from lens.

This is starting to become a bit more of a science experiment than I had originally expected but, okay, I'm up for the challenge. I will repeat the photos this weekend, plus will add some size reference to the images (I'll figure something out), and will add the other photos I was planning.

I wish there was a way for me to place ALL the photos, arranged side by side, in one post. The 5 photos per post limit is going to make this somewhat confusing to read. Any moderators out there have an idea?
 
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A further refinement of the study

How about showing the same edge after 20 seconds of cutting some basic maple at the same RPM.
Then at 1 minute. Or different type of wood after a set time.
It would be interesting to see how much, or how little the starting edge quality matters after use.
 
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Seriously Mark? Maybe a project for sometime in the future.

Here are my plans for this weekend photos:

Compare:
CBN dry wheels at 80 and 120
Tormek grey wheel at 220 (rough graded) and "1000" (fine graded) unhoned and honed edges.
Tormek CBN wet wheel (280 grit) unhoned and honed

I will also photo a fresh/unused surgical scalpel blade for true "scary sharp" comparison, and will find some scale reference to place with each micrograph.

I will put this together as a single PDF document, an will post it in this thread (or a link to it anyway). That way, it will be easier to understand and use. It will also allow me to provide higher resolution and a size that is more conducive to presbyopic vision (old eyes).
 

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Jeff, just to get sense of absolute scale of these pix, would it be possible to lay a fine wire of known size, say 30 gauge along gouge when you take one of the pix?
 
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How about showing the same edge after 20 seconds of cutting some basic maple at the same RPM.
Then at 1 minute. Or different type of wood after a set time.
It would be interesting to see how much, or how little the starting edge quality matters after use.

Excellent idea, but more appropriate when doing wear studies with different alloys. I seem to remember such a study done some years ago with PMs in various alloys. IIRC it sort of debunked the justification for the difference in price between V-15 and 2060 over their lesser cousins, A-11 and 2030, for bowl gouges.
 
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Sorry. I thought it seemed reasonable.
A mirror shined sharp gouge on the shelf is a trophy.
regardless of the method used to obtain the shine.
The goal is to turn something with the tool, right?
At what point would I need to return to the sharpening system to keep the high quality cut.
I guess there are way too many variables to be objective.
 

john lucas

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Mark I was at that demo and the test results really didn't duplicate turning very well. He used odd angles on the tools and I forget what else we discussed later that left us with dubious results on his tests. I'm doing a comparison on how sharp the 3 types of tools get, Powdered metal, HSS and High Carbon Steel. I'm still trying to figure out a way to do some kind of test to get some wear results and then get micro photographs. That may take a while since I'm getting ready to start battling the Prostate Cancer I have. Hopefully it won't slow me down for long.
 

Mark Hepburn

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Mark I was at that demo and the test results really didn't duplicate turning very well. He used odd angles on the tools and I forget what else we discussed later that left us with dubious results on his tests. I'm doing a comparison on how sharp the 3 types of tools get, Powdered metal, HSS and High Carbon Steel. I'm still trying to figure out a way to do some kind of test to get some wear results and then get micro photographs. That may take a while since I'm getting ready to start battling the Prostate Cancer I have. Hopefully it won't slow me down for long.

John,

Off topic here but I had prostate cancer (Gleason 7) and underwent a RRP just over two years ago. Because of other health issues I wasn't a candidate for brachiotherapy or chemo. So out with the prostate and here I am two years later cancer free and with no lingering post operation issues. I'm glad I did it. Took about six weeks to get back to work and feeling somewhat normal again, though.

I know some may think this is "too much information" but c,est la vie. I researched like a madman and feel like i made the best choice. Now it happens that three friends in my office have recently been diagnosed so we have spent a good bit of time discussing.

I wish you well in your battle,


Mark
 
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ouch and a suggestion

A time when the off topic is more important than the thread subject. John, good luck with your treatment. I have never had cancer but there have been a couple of biopsies. I do know even maybe preys on the mind, having to be treated has to be far worse. Wish there was more to offer to help but at times like this others are pretty helpless. I do know you have a world of friends just on the turning sites to support you.

Jeff,

Maybe just a finely graduated steel rule by your edge for reference or open a mike or caliper to a set distance the same in each picture to give an idea of scale. Shouldn't need to be too complicated. Any kind of standard will work, even laying the shank of the same drill bit by each piece photographed.

I do much appreciate what you are doing and don't want to turn a simple thing into a monster project. I made the mistake of mentioning that my CAD software could position objects on a ten mile radius map within 3/8" of where they were reported to be. A few minute upgrade on a drawing turned into a three month project! Was worthwhile though, radiation monitoring sites if we had a release at the nuke.

Thank You for doing this!

Hu
 
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Mark... Glad you are okay. As a physician who does that sort of surgery all the time, it can be very daunting to wade through all the information.

Sorry, didn't mean to sound flip. I have so many things to do for this project this weekend, that I don't think I'll even get to do any real woodturning. Oh well. Shop needs cleaning anyway.

I am going to try to find something here at the hospital that will show micro millimeter rulings. Don't have a ruler at home that has that much resolution.

I do think it would be nice to see how long it takes to dull an edge, o remove a burr. There's a lot of conjecture out there, but no real experimental data that I know of. Maybe we can generate some here. My problem with that is, I think I can only accurately do that test with a scraper. The angle of attack, even in bevel rub mode, greatly affects the amount of wear placed on a blade. Scrapers, on the other hand can be pushed into the wood in identical fashion time and time again. Unless someone has a better idea, I think that's how I shall proceed.

Oh, and I definitely want to test burr durability... For Robo.
 

john lucas

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Jeff I'm making some chisel shaped tools for my test with the edge square across like a carpenters chisel. I've been thinking about putting the chisel in my metal lathe. advance the cut a known amount into the work as it rotates and then use the power feel to go from one end of a turning to the other. maybe make 2 or 3 passes with each tool and then look at the edges. Don't know if that will be enough to really dull them. I would have to use 3 pieces of wood all cut from the same board so maybe the variable wouldn't be too bad. These tools would be the same ones that I will have sharpened by a professional sharpening service so hopefully the edge would be about as good as it can get.
 
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John. I think that sounds about as controlled an experiment as you can get with this sort of thing. If you do that, I'll do the others. The only thing I can think of, is that the force exerted on the edge of a turning gouge is higher per unit than a square gouge. It should skew the results towards longer edge life... At least that's my guess. Still a useful experiment.
 
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Mark Hepburn

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Mark... Glad you are okay. As a physician who does that sort of surgery all the time, it can be very daunting to wade through all the information.

Sorry, didn't mean to sound flip.

Thanks Jeff. You're certainly right about the quantity (and dubious quality) of information out there. And I have to say that, having been through it, I have a real respect for those of you who are called to the profession. Now THAT is daunting!

Oh, and I definitely want to test burr durability... For Robo.

You'll make Robo a happy man if you can do that :)
 

Mark Hepburn

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Jeff I'm making some chisel shaped tools for my test with the edge square across like a carpenters chisel. I've been thinking about putting the chisel in my metal lathe. advance the cut a known amount into the work as it rotates and then use the power feel to go from one end of a turning to the other. maybe make 2 or 3 passes with each tool and then look at the edges. Don't know if that will be enough to really dull them. I would have to use 3 pieces of wood all cut from the same board so maybe the variable wouldn't be too bad. These tools would be the same ones that I will have sharpened by a professional sharpening service so hopefully the edge would be about as good as it can get.

This may be a dumb idea, but how about using some MDF formed up into blanks? It's a consistent medium and from what I understand not too forgiving to turn with? Just a thought.
 
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These tools would be the same ones that I will have sharpened by a professional sharpening service so hopefully the edge would be about as good as it can get.

Don't count on that result, John. I tried that with a couple of guys in my area just to see how they would do. Chisels came back with nice sharp burrs on even hollow-ground bevels that lasted about a inch in wood and then went dull. Except for large saw blades I do all my own sharpening now; from hand tools to chain saws.
 

john lucas

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Mark this guys knives are exceptional. I doubt they will come back with a burr. I just got the first 2 chisels done today. The Powdered metal and the HSS. I ground the angles identical and it came out to 28 degrees. I sharpened them on my scary sharp system. Man are they sharp. So far I can't tell the difference in these 2 in sharpness. Cuts paper effortlessly and or course cuts hair. I'm tempering the High Carbon steel to 60 rockwell and will sharpen it tomorrow after it cools down.
I am thinking about running a test after I get them back and photograph the edge. If I put a piece of wood on my metal lathe and set the tool in carriage at the same angle I can advance the tool into the wood maybe .100" and let the power feed run it across the wood. Do this about 3 or 4 passes or until the I think the tool isn't cutting the same and then try to rephotograph the edges. Do you think this would roughly be accurate at all.
 
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Hi John,

No intent to take anything away from your "guy." A good job done is always worth it.

Noting on your carbon steel. I know you know enough about steel to know that until you get to the molecular level, any alloy will sharpen to the same degree of fineness provided you use the same abrasive on each. It's an internet myth that Carbon Steel will give a sharper edge than High Speed or high alloys. The determining factor is the abrasive. A 400 grit wheel will leave a 400 grit edge on everything it touches. Carbon steel "can" be taken to a finer edge than ASP-2060 or V15 because of its smaller crystalline structure, but you need very special equipment, far beyond anything we woodworkers (or your sharpening guy) have to use.

It'll confirm that HHS and PM are more durable than carbon. But you already know that. The pix will be fun, however, to see how much each edge is degraded.
 
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john lucas

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I've been toying with using MDF or particle board simply because it might be more abrasive and at the same time more consistent. I'll have to look around and see what's available locally. I sharpened the chisels so far up to 1500 grit and then touched them on a leather strop to finalize the edge. That's as sharp as I get my hand plane blades and they cut wispers off wood. When I took slices off a piece of paper I couldn't believe how easily it cut. Probably not as easy as the floating silk in the movie Bodyguard (which myth busters proved wouldn't work anyway).
 
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One thing with MDF, other than being terribly dusty is that it is not consistent. The surface is more dense than the interior. I would guess that it is pressed in single sheets unlike standard plywood which can be stacked several (30 plus) high. The inside does not compress as much. I am not sure how much difference that would make.

robo hippy
 
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