Is there any difference between...

[odie]

Is there any difference between...the degree of sharpness that can be acquired on the common M2 steel tools vs the degree of sharpness that can be acquired with the more expensive exotic steel tools?

-o-

 

[Steve Tiedman]

Yep, and it's probably best demonstrated, visually, under a microscope.

Various alloy blends may, or may not, improve the utimate ability to obtain a perfectly keen(er) edge, more likely they improve the wear resistance of the overall steel alloy blend, allowing an edge, built for the task, to last longer.

Some of the very best, most incredibly sharp edges can be found on hand carving tools, which more often than not are simple carbon steel alloys. Incredibly sharp, but they can't take the abuse of turning as well as the more heavily blended alloys, which may, or may not, be able to provide the same keen edge as some simple carbon steels. These alloys may sacrifice a wee bit of keen edge ability (they'll still slash my flesh open!), but they make up for it in toughness/wear resistance. It's all a give/take balance for the job at hand.

 

[odie]

These alloys may sacrifice a wee bit of keen edge ability

Do they really, Steve?

Interesting!

I've come to the understanding that the exotic steels have the capability to achieve the same level of sharpness that the M2, or carbon steels do.

...but, I'm open to further discussion/input on that.

-o-

 

[George Kuipers]

I just sharpen when the tool is dull, steel or no steel.

 

[Timothy White]

@odie exotic steels can be sharpened just as sharp as carbon steel but not with the same medium.
@Neil S. Has a really good post about tungsten carbide bowl gouges. He gives good information on sharpening TG.
Im going to make a positive statement here!
ANY steel ground on an 80 grit “stone” is not sharp or any where close to it.

 

[Brian Deakin]

Simply sharpen before your do your final cut

 

[robo hippy]

This is one of those debates that never goes away. It seems that the usual conclusion is that any edge can get equally sharp with any metal, but some are easier to get there than others. Possible exception might be the micro/nano grained carbides, and maybe the ceramic kitchen knives. I made a bench chisel and some marking knives out of some M42 HSS, and was told on the flat work forums that I could never get the edge as sharp as the A2 steel, which is one of the favorites. Well, as near as I can tell, it took the same fineness of edge as I sharpened up to 10000 grit and stropped the edges. They now use a PMV11 blade for plane blades. Sharpness and edge durability are some what different, but durability depends on hardness, and on bevel angle. I did see an interesting video on resharpening ceramic kitchen knives. It wouldn't take a good edge from a 1200 grit diamond stone, but a 3 micron diamond lapping paste on an MDF wheel got the edge back. His theory was that the coarser lapping plate did remove material, but because of the coarseness, it would chip the edge of the blade. Quite possible. He didn't have sharpening stones finer than 1200. Maybe 8000 would help.

robo hippy

 

[William Rogers]

I think I remember @john Lucas did some microscope photos of different steels edges. I couldn’t find it, and maybe I did not remember exactly what he did.

 

[odie]

@odie exotic steels can be sharpened just as sharp as carbon steel but not with the same medium.
@Neil S. Has a really good post about tungsten carbide bowl gouges. He gives good information on sharpening TG.
Im going to make a positive statement here!
ANY steel ground on an 80 grit “stone” is not sharp or any where close to it.

Yes, that's what I believe is correct about the exotic steels.....they are capable of every bit as sharp of a cutting edge as any of the more common HSS turning tools. The only difference is their enhanced ability to hold an edge is much greater.....and, from My POV, extreme edge holding ability ultimately becomes a disadvantage for woodturners. I've spoken about this many times in previous posts.

I should clarify here that my use of an 80gt wheel is only for the purpose of removing metal, and never to create a final cutting edge on gouges. Every one of my gouges have edges that are hand honed, both on the flute side AND the bevel side....always. Most of my scrapers do use the bur directly from the 80gt wheel, and for that, it works fine for general purpose roughing work. When I want to use scrapers for final finish work just prior to sanding, the ground bur is removed with a flat diamond hone, and a more perfect bur is manually raised.

-o-

 

[odie]

I think I remember @john Lucas did some microscope photos of different steels edges. I couldn’t find it, and maybe I did not remember exactly what he did.

Although I haven't had the ability to provide photos, I have a small microscope that I've used to personally inspect the cutting edges of my tools.

-o-

 

[Bill Alston]

As I understand it, sharpness is largely determined by the grain structure of the steel? The finer the grain the sharper it can be honed. Honed being the operative word here. Many folks don’t seem to go beyond 180 grit so I doubt that’s approaching anywhere near the sharpness that most wood turning tools can support. Carving tools need to be very sharp as unlike wood turners they don’t use sandpaper afterwards.

 

[Perry Hilbert]

i do not turn any thing particularly fancy, but I do have a few favorite older carbon steel tools. Easy enough to sharpen with a few strokes on a stone. and for a final cut seem to do a much finer job. The edge certainly does not last as long as HSS or others modern tools. depending on the species of wood, I do not have to sand at all. which is still amazing to me. I can get close with some modern tools, but never quite that smooth.

 

[Rusty Nesmith]

A good friend of mine says he can get his Sorby tools sharper than Thompson but the Thompson will stay sharp longer.

 

[Bill Alston]

i do not turn any thing particularly fancy, but I do have a few favorite older carbon steel tools. Easy enough to sharpen with a few strokes on a stone. and for a final cut seem to do a much finer job. The edge certainly does not last as long as HSS or others modern tools. depending on the species of wood, I do not have to sand at all. which is still amazing to me. I can get close with some modern tools, but never quite that smooth.

Yes, it seems to be a trade off with HSS. Not as sharp as carbon tool steel but tougher, being able to hold an edge longer.
I’ve got a Crown M42 “Razor Edge” spindle gouge and it doesn’t seem sharper or hold an edge longer than my old Henry Taylor Diamic gouge.
I’ve recently decided to finish sharpening a couple of my tools with an 800 grit belt to see if it makes a noticeable difference. I’ve polished the flutes as well, but I’ve not had chance to try them out yet.

 

[Jim McLain]

I recently purchased an A11 steel 1/2 inch bowl gouge from Ashley Harwood and I was very impressed with the sharpness she achieved. I think a big part of it is how well polished the flute is. Have to say this is probably the finest A11 steel tool I have ever purchased or used.

 

[Doug Rasmussen]

There's a factor that may be more important than sharpness, that's the included angle of the cutting edge.

A kitchen knife has an included angle (just guessing) of maybe 2 to 3 degrees. What's the included angle of a bowl gouge, 30 degrees? A dull kitchen knife will slice a tomato better than the sharpest bowl gouge.

Way back in the day as a hobby project I rescued a 1930's automatic lathe going to the scrap yard. That machine was a Rube Goldberg mechanism with levers and cams operating it. They used different type tools than modern automatic lathes, each part's design required a custom formed knife. For instance, to turn a ball imagine a piece of tubing. Remove the bottom half of the tube. Then sweep the edges back. The cutter sort of peels the work with the top of the cutter first hitting the largest diameter of the ball like peeling an apple and the swept back edges shear cut both sides of the ball. While the edges of the ball are being shear cut the top of the cutter passes over the ball. Those cutters were carbon steels with a few degree included angle and honed when needed, never ground except when being made. On the cheap these cutters were made from car leaf springs. Surprising how nice a finish these type tools could do. A cutter might run for half a day without needing honing.

The relief angle of a cutter is important. The picture shows an ideal cutting scenario, the relief angle between the work and cutter is only a couple degrees. Conventional gouges can't do this as well as hook tools.

Top

I've mentioned the ultimate carbide woodturning insert about a million times. They're known as a high positive diamond insert since then have a relatively low included angle and razor sharp cutting edges. Arizona Carbide lists carbide diamonds, none high positive though. Hand turners don't use them because they're too aggressive with a tendency to dig into the work unless they're rigidly held (which can't be done by hand turners).

 

[Steve Tiedman]

This evening I thought I'd set up my camera and take some macro shots of edges on a bowl gouge and some other tools. Suffice it to say, I stopped at the bowl gouge. These photos cannot show alloy grain structure, that the job of high power microscopes.

These photos are not as though the edge is under a microscope, nor did my setup lock the tool into the dead exact position each time to make the pics as apple-to-apple as possible. Take this all for what it's worth, funtime with my camera. (Camera info- Pentax K3-III Monochrome, B&W capture only, and a Pentax 100mm macro lens.) JPEG files transferred to my phone and the images cropped a little bit, and contrast increased to highlight the grinding marks. I haven't viewed the photos on a computer screen yet, but that will be the best place to see them, something bigger than a phone. The gouge is a 1/2" Crown Pro-PM powder metal, Ellsworth grind.

60 grit aluminum oxide wheel that looks like it could stand a dressing. (Edit- now I'm looking at the photos on a computer screen. That ain't no edge! It's crap! But yes, it will remove the surface of a spinning lump of wood.)



Jig at the same angle but moved to a 180 grit CBN wheel, 6 full sweep strokes moved across the wheel at a moderate speed with light pressure. Some waste burr is visible on the edge. That disappears instantly when in contact with the wood, the waste burr is not a usable cutting edge. (Finger pressure removes it.) For gouges, this is the wheel I use to get an edge to cut wood, I don't go any further with hones or strops. Maybe I should. Edit- I go from the wood to the 180 and back to the wood. I will hone with skew chisels, using a 600 grit diamond, wood to hone to wood, no wheel until the bevel hones flat. (Hey, old-timers, remember when we sharpened at a 100 or 120 grit al. ox. wheel... 20 years ago?)



Below, after 5 or 6 careful strokes with a 1200 grit diamond hone to remove the waste burr and refine the very edge to lessen the diamond chip grinding grooves in the steel. Now we're getting sharp. Depending on how the light reflected off the bevel at the edge and heal, you'll see black or white lines right at those edges. Those are not present in the previous shot because the edge is still more like a hacksaw than a razor blade. The hone did not touch the bevel between those two lines due to the radius of the wheel leaving a concave bevel surface.

 

[Timothy White]

A good friend of mine says he can get his Sorby tools sharper than Thompson but the Thompson will stay sharp longer.

That is an almost true story. The reason Sorby tools can be made sharper than DT’s is because the Sorby flute is polished. I’ve been working on the flutes of my Doug Thompson gouges with an Alan Lacer diamond slip stone for a few years now. The better the flute gets the sharper the gouge gets and the longer the edge lasts.

 

[Bill Alston]

Thanks for posting the photos Steve. I’m not surprised at what I’m seeing in them. As you say a 60 grit wheel will produce an edge that will happily remove wood but it’s hardly what many would call sharp.
I have tried and failed to take some macro shots of the edge of one of my scrapers but I’ll try again with one of my gouges.

Timothy, the flutes on wood turning gouges seems to vary quite a lot between manufacturers. Some have a very nicely finished flute whilst some others leave a lot to be desired.

 

[Steve Tiedman]

Bill, I agree. I have one 3/8" Sorby- polished, shiny flute. I have one P&N 5/8" from their early days, darn near a mill finish, maybe a finer grind than 180. The rest of mine are Crown Pro-PM. The flutes are nicely smooth but not polished. The factory flute finish, or your flute finishing efforts, does make a difference on edge quality, for sure.

 

[Bill Alston]

It seems that many turners feel it’s a waste of time honing wood turning tools. I read an article a little while ago by a professional turner and he disagrees. A nicely honed tool, particularly on finishing cuts, can reduce the amount of sanding required. This can be quite important in preserving any crisp edges in the design.

 

[odie]

It seems that many turners feel it’s a waste of time honing wood turning tools.

^^^^^ This is the result of "herd think".

Most new turners will spend a small fortune on tools where the commercial strategy is to prolong needed trips to the grinder, and eliminate the need to hone. This is very attractive to those who are just starting out in woodturning.....and IMHO, sends new turners down a long frustrating path that ultimately ends in disappointments that could have been avoided by developing more traditional and long underappreciated skills. I can remember feeling very discouraged with my grinding/honing skills early in the learning process.....and, I'm thankful that I stuck it out using tools, grinder wheels, and methods that are no longer in vogue. My previous lifestyle was one of exclusion from the outside world that most other turners exist in.....and this enabled me to avoid being influenced by those who have something to sell us, or those who have invested $$$ in their products. At that time, and for a period of about 25 years, the only external influences I had, were a few woodturning books, and a few early VHS tapes on turning.....quite literally nothing else, but me and my lathe, and lots of time on my hands!

When I need to return to the grinder, and re-hone, it's so fast and easy, that it's just something that's done without any cerebral effort. This process has been refined to the point where the results, BOTH on the quality of my sharpened edges, AND the results on my turnings.....are distinctly noticeable to me......EVERYTHING benefits by that refinement, but it does take quite a bit of effort and perseverance to achieve it. Nobody else will notice these things.....but, YOU certainly will!

-o-

 

[robo hippy]

How clean your surfaces are before you start to sand depends on a number of things. One is wood species. There is how sound is the wood as in fresh and solid or soft and punky. There is also your 'finish cuts', which is probably one of the most important factors.

I am not sure about the idea of the specific metal when it comes to 'particle' size. Some used to claim that the sharpening stones would pull out particles the size of the particles, and not just shave off the particles. I can see this being true with very coarse stones, but maybe not true with the very fine stones. No clue as to how they get the polished edges on the carbide tools. I can get my tantung scrapers to an extremely fine edge by honing and stropping, and can get surfaces as clean as I can with a skew, and yes, my skew skills are not legendary, well, other than being ho hum.... Tantung is a particle metal which is cast, if you are not familiar with it.

robo hippy

 

[Michael Nathal]

Alan Lacer has an excellent article on honing in Am Woodturner Spring 2003. He has a second article (Summer 2009) with lots of photos of sharpened edges. He is mostly comparing the older grinding wheels and hand honing with a diamond hone, but also covers power honing . Tom Wirsing also shows similar photos of edges in June 2018. He is emphasizing CBN wheels.

 

[Bill Alston]

Thanks for mentioning the name Michael. I did a search and found the article I read a while ago:

https://alanlacer.com/resources/Honing-Turning-Tools.pdf

 

[Aaron Harris]

Here's a little different perspective from a turner who probably has a lot less experience and skill than many of you old salts. I come from a background of straight razor restoration, so being obsessed with a super-fine edge is part of it. Obviously this is an absolute requirement when shaving tender facial skin smoothly. So for my 1st three years or so of turning, I definitely subscribed to the hone everything very fine school, even to the point of stropping my skews honed with 600 diamond cards further on diamond-spray laden fire-hose strops!

And then I attended Matt Monaco's Skew class at our Turning Learning Center late last fall. I was dumbfounded to watch him sharpen his skews on the coarsest 46 grit stone wheel in the shop every time. He doesn't hone off the burr, or hone ever, really. And his edges look as ragged as you would expect off that wheel. But his finished surfaces on the maple spindles he was demoing on were literally glass smooth, better than I can get from sandpaper if I'm honest. Of course his fine tool control is what makes the difference. I was gobsmacked, still am. I signed up for his weeklong class at Arrowmont in June hoping I can absorb some more of that tool control along with his other skills.

Only tangentially related to the OP, but it just goes to show "there's more than one way to skin a cat."

edit to add: I am still far too early in my turning and sharpening journey to have developed dogmatic thinking in this area, so am not trying to generate any controversy at all (I used to watch grown men actually get mad over different razor honing techniques on the straight razor forums with sad bemusement). It just amazes me what turners with vastly different approaches can accomplish if they "hone" their skills using their favorite techniques. I learn something from all of them.

 

[Steve Tiedman]

Aaron, your observations and experiences are spot on in demonstrating the poor cat techniques! And you will find that what works for one turner/craftsperson/artist may not be for you, and vice-versa, but neither are necessarily wrong.

Photography is another hobby of mine. "Wow, great shot, what camera and lens did you shoot that with?" Every time, they (mostly other photographers) ask about the gear more than the scene, conditions and setup.

Personally, I've never heard anyone say "Wow, great bowl, what gouge and edge grinding method did you use to make that?" I dunno, maybe someone has asked that.

In the end, like you're pointing out, it really doesn't matter which lens or gouge I used, it was my skill that got me to the finished product. All the best on your continued trek in the turning world.

Now, those fire hose strops, do you prefer them to suade-side and/or smooth side leather strops? Suade on wood with Lee Valley-Veritas green compound for me for woodworking tools. (Because that's what I know...!)

 

[Neil S]

@Neil S. Has a really good post about tungsten carbide bowl gouges. He gives good information on sharpening TC.

The durability of an edge is something that we can measure. Those measurements can be useful to others if we specify the criteria on which we made our judgement that a particular edge profile made form a particular metal composition had stopped cutting a particular material.

But sharpness is a far more subjective judgement. A lot of personal preferences go into making those judgements and they are not readily conveyed to others. Not least among those is the judgement on how much time and effort would be required to bring an edge backup to a preferred degree of sharpness balanced against how well (not how long) it is cutting for you at the time.

I sharpen many different types of cutting tools for different purposes; going from high-end Japanese hand forged kitchen knives using natural stones up into the #20-30k grit range, down to firewood splitting axes, and large one and two-person hand saws in between, to name just a few. I spend a lot of time looking at edges under magnification, but what is a useful level of sharpness on a tool for one purpose would be totally unproductive for other purposes. What I might judge to be sufficiently sharp may be very different to what you or others may decide.

When I'm turning the final cuts on punky piece of wood I prepare or reach for the 'sharpest' tool I have to do that. I know the preferred level of sharpness that I want for that purpose and its durability at a lower level of sharpness is of little interest at that stage of the job. However, for most of the time I'm turning I'm after durability. I want an edge that will get the bulk of the job done with the least number of trips to the grinder.

What then can I say that might be useful to other... in broad terms, the larger carbides in some of the 'exotic' woodturning tools we use provide more durable cutting edges, while others with finer carbides can take a finer edge (as seen under magnification) but usually don't hold their edge for so long.

The extreme end of that is good quality plain carbon steel like they use in razors, which can take the finest of edges, which is ideal for shaving, but is almost gone instantly if used to turn most woods.

At the other end is Tungsten Carbide that (in most grades) will never feel really sharp, but will cut 'satisfactorily' for longer than most of the other turning tool steels we use and particularly with the tougher woods.

In between we have steels like M42 that have a finer grain structure that take a beautifully sharp to the feel edge that is excellent for finishing cuts, but not quite as durable as some of the other HSSs.

M2 also takes a very fine edge, but is not as durable as M42

Among the more durable edge steels are Tantung and the vanadium steels. Of those a 15% vanadium is robust but is harder to put a fine edge on. A10% vanadium tool is a two-way bet, it seems to take a slightly finer edge but is not quite as durable as the 15% vanadium.

Much is made of the heat treatments used on the various steels. The bottom line there is it should be optimised for whichever steel it is being applied to, but the significant differences comes from the steel compositions.

The comparative cost of the tools and the abrasives we use to sharpen them are, of course, other factors that come into our judgments.

I've posted the following results of my testing elsewhere on the forum, so just added here without details. See how the 'sharpness' of the finer carbides in M42 does very well with fine finishing shear cuts but not so well in its durability with heavier push cuts. The Tt steel was for Tantung.

And the following shows the benefit with various woods of a grinding to a fine grit

​

 

[John Ames]

If you're asking about microscopic sharpness, then theoretically, carbide size can make a difference in absolute sharpness. For that reason fine grained low alloy steel is generally chosen for use in razors.

So, 12C27, which is pretty much formulated for razor blades, will potentially be able to get sharper than D-2, which is formulated to have large carbides.

However, you will only be able to see the difference at extremely high levels of polish and with a very thin edge.

Powder steels are manufactured to a specific grain size regardless of alloy content, and should all be able to get pretty darn sharp.

If you're asking about lathe tool sharpness, specifically, the ability of the person doing the sharpening will make all the difference. The metal's ability to hold an edge is a different question...

 

[Larry Mercier]

It just amazes me what turners with vastly different approaches can accomplish if they "hone" their skills using their favorite techniques. I learn something from all of them.

 

[Bill Alston]

I’ve realised there’s quite some difference between what some folks understand when we talk about the term “Honing”.
I mentioned this topic to someone the other day, and honing to them means passing a 300 grit diamond plate over the tip of a bowl gouge when it gets a bit dull. Honing to me on the other hand is using a 800 grit belt to polish the whole bevel after sharpening. Neither is right or wrong, just an observation.
I’ve ordered some small stitched mops to see if power stropping makes a difference. This will be for spindle gouges, I don’t do much bowl turning or faceplate work.

Edit: I found this yesterday, it’s quite a comprehensive treatise on sharpening! I’ve yet to read it all.

https://www.mnwoodturners.com/cms-files/sharpeningturningtoolsbookdo.pdf

 

[odie]

edit to add: I am still far too early in my turning and sharpening journey to have developed dogmatic thinking in this area, so am not trying to generate any controversy at all (I used to watch grown men actually get mad over different razor honing techniques on the straight razor forums with sad bemusement). It just amazes me what turners with vastly different approaches can accomplish if they "hone" their skills using their favorite techniques.

I may rant about my own discoveries in woodturning, but I ultimately do subscribe to the philosophy of "I'm OK, and you're OK"! If someone else is good with their results on the lathe, then that's fine with me, and accept it.

However, from my observations I've noticed that quite a few turners are satisfied with a tooled finish that requires aggressive sanding to get rid of the torn end grain, uneven surfaces, and tool marks. For those who embellish their turnings, this may be perfectly acceptable because they rely on sanding to eliminate what they consider inconsequential flaws......but, for my kind of turning, where the subliminal attraction relies on perfect geometry to gain the desired aesthetic appeal, it's not acceptable. In order to maintain the perfect geometry, then the turning skills, along with the right tools and techniques are essential to have a tooled surface in preparation for a very minimal amount of sanding. Aggressive sanding of bowls, being that they are side grain orientation, and the resistance to sanding alternates as it spins on the lathe, means the geometric integrity suffers a loss of perfection.....or, roundness. This loss of geometric integrity is what destroys the ability to achieve the aesthetic appeal my turnings rely on for visual acceptance by those who purchase them. They may not know just what it takes to gain their approval, but they know what they like, and most, if not all of them have seen or purchased turnings from other turners prior to making their comparisons and judgements.

^^^^^None of this will make much difference to many other turners, but for a select few, these things are essential.

-o-

 

[john lucas]

I have not read this whole thread. Way too long but I might try. I did my own tests. I ground high carbon steel , m2 steel and A11 particle metal to 2000 grit. Then honed them further. Then viewed them under an electronic microscope. I forget the magnification but it was very high. All 3 metals sharpened to the same sized peaks. Then I tested them on a commercial sharpness tester. All tested very close to identical.
However the test I'm doing right now shows me that for turning tools how polished the edge is barely matters. I know I'll take some flak over this but I've spent the last week turning all kinds of wood with various tools. I sharpen the tool on a 36 grit AO wheel. Make a cut. Then sharpen on my 350 cbn wheel. In most cases I cannot see the difference in the cuts. It us important to not cut the wood any faster than the wood wants to be cut. I use a very short main bevel so I can feel the cut. This travel rate us slower than you might think but that makes far more difference in the cut than the grit you sharpen with. Testing still going on.

 

[Aaron Harris]

I have not read this whole thread. Way too long but I might try. I did my own tests. I ground high carbon steel , m2 steel and A11 particle metal to 2000 grit. Then honed them further. Then viewed them under an electronic microscope. I forget the magnification but it was very high. All 3 metals sharpened to the same sized peaks. Then I tested them on a commercial sharpness tester. All tested very close to identical.
However the test I'm doing right now shows me that for turning tools how polished the edge is barely matters. I know I'll take some flak over this but I've spent the last week turning all kinds of wood with various tools. I sharpen the tool on a 36 grit AO wheel. Make a cut. Then sharpen on my 350 cbn wheel. In most cases I cannot see the difference in the cuts. It us important to not cut the wood any faster than the wood wants to be cut. I use a very short main bevel so I can feel the cut. This travel rate us slower than you might think but that makes far more difference in the cut than the grit you sharpen with. Testing still going on.

John-I don't know if you read it yet, but this is essentially the eye-opening observation I made repeatedly in Matt Monaco's skew class, except it was a 46-grit wheel, so about the same, really. I had been obsessively honing my skews especially based on advice here and watching Alan Lacer's videos, and then I wondered if I really need to be wearing myself out honing to light-saber sharpness when glass smooth surfaces with no tear-out are possible off the low-grit wheel (at least in MM's hands-mine are still a work in progress).

I guess my compromise since that revelation is grinding my skews on the 80-grit 1.5" CBN wheel (coarsest and biggest I have), then hone with the Lacer 600-grit slip-stone a few times before a refresh on the wheel so I'm not constantly grinding off steel from an already concave bevel. As the art and science of sharpening is something I am endlessly fascinated by, I am always experimenting to see what works best. I think the most important thing I've done is set my grinder up literally behind me at the lathe, where all I have to do is turn around for a quick refresh.

Turning and sharpening are part of the same continuum, I have learned, and should only be considered as to how they work together to achieve the best results. In fact, learning how to grind deliberately to complement the way I cut with any given tool has helped me up my turning skills almost more than any other factor.

edit: And Odie, your obvious precision off the tool with minimal sanding is evident in every one of your unique bowls. I am slowly getting there, because I am really tired of excessive sanding, the bane of every beginning turner I guess! Learning some of Ellsworth's more advanced finishing cuts in person last summer helped a great deal with this. Then my grail quest was the perfect curve and more advanced work on the fundamentals, which is exactly what I got from David's class. This summer's goal for me is much finer tool control and the ability to create the classic, elegant shapes, which is why I chose Monaco's Arrowmont class. The learning never stops.

 

[Steve Worcester]

My understanding is that "lower quality" of steels, i.e. low carbon then HSS (M2) then up M3, M4, then Mx with Vx, can be sharpened finer from the left to right, but because of the lower grades of steels inability to hold the edge, that steels fine edge advantage is gone and the mid and upper grade steels (m2 and up) hold their edge longer which results in less sharpening to maintain the same quality of cut.
With that said, there is still a lot of science in the hardening and tempering which also contributes to the cutting and edge holding ability of the same steels.

 

[Bill Alston]

If you look at the document link I posted earlier the photographs are quite compelling. The difference between just grinding and honing as well is obvious.
A couple of screen shots, but do take a look at the document.

 

[Neil S]

Testing still going on.

John

I look forward to reading your results.

 

[Roger Wiegand]

It may well be that for an expert the edge from a 46 grit wheel can give astonishing results, I'm not disputing that. What I have observed is that for a turner of very mediocre skills (me) honing allows me to eliminate tear out and produce a much nicer surface than I'm able to get before I hone. When the cut isn't going well I frequently hone and find it goes much better. If I were a better turner it might well make less difference. A sharper edge is, for me, more forgiving than a duller one.

There are some wonderful videos of a Japanese lab that studies sharpness and different sharpening approaches using a robotic plane and high speed microphotography to see what's happening at the cutting edge. They are well worth finding and looking at, more relevant to how you set the breaker on your plane, but fascinating nevertheless. Sadly I can't find them now.

 

[Neil S]

If you look at the document link I posted earlier the photographs are quite compelling. The difference between just grinding and honing as well is obvious.
A couple of screen shots, but do take a look at the document.

View attachment 60020

View attachment 60021

Bill

What needs to be added to those images is the grit sizes that Lacer & Wright used for their experiments, which can be read starting on
Pg58 of their articles you linked to.

The first tool edge image in each sequence is off a #60 wheel. The second is off a #600 diamond 'hone'.

However, if you were to refresh the edge of a tool on a #600 or #1,000 wheel are you grinding or honing it. The term 'hone' had more meaning back when grinding stones were always a coarser grit than hand honing stones. With grinding wheels available now going up to #1,000 or more the term 'hone' has a less precise meaning.

This is not a criticism of the Lacer & Wright article, which is an excellent piece of work at the time they conducted it. What we can take from their article is that grit size makes a difference and as long as you nominate the grit size you are referring to you can call the process whatever you like. I have several devices that I call hones and all they do is 'sharpen' to a finer grit or micron size. It's all just 'sharpening' along a grit continuum.

 

[Neil S]

I’ve been working on the flutes of my Doug Thompson gouges with an Alan Lacer diamond slip stone for a few years now. The better the flute gets the sharper the gouge gets and the longer the edge lasts.

Absolutely!

And, once you have removed the roughest milling tracks from the flutes you can then go quickly down to very fine grit sizes with a rag wheel and cutting bar compounds. Once that is done I maintain the polished surface of my flutes with chromium oxide (it's approx half a micron) loaded onto a rag wheel mounted on a bench grinder. I do that about every 5 bevel touch-ups and it takes just a few seconds to do.