Sharpening Bowl Gouges

[William Rogers]

This subject came up in another thread. Limiting to bowl gouges in this poll. Not looking for a debate, but what others are using doing to sharpen their gouges and if they hone them. You can vote as many thing that apply. I use both 80 an d 180 grit CBN, so I would vote both of those.

 

[Roger Wiegand]

Another option-- I hone many times (10-20) between trips back to the grinder to re-establish the edge.

 

[William Rogers]

Another option-- I hone many times (10-20) between trips back to the grinder to re-establish the edge.

Good point. I added that to the poll, Thanks

 

[Brian Gustin]

Yet another option - I hone SOME tools after sharpening on grinder, but not ALL (Some I don't bother, some you'll WANT the burr)

 

[odie]

Another option-- I hone many times (10-20) between trips back to the grinder to re-establish the edge.

Same here.

-----odie-----

 

[odie]

Just to clarify......I do not go to the grinder to "sharpen", as the poll suggests. The purpose of my grinder is to remove metal, and I'm using a Norton 80gt SG wheel for this purpose. I depend entirely on the honing process to create the cutting edge itself.

-----odie-----

 

[Monty Ivy]

I don't hone exactly. The RS Pro-Edge allows the use of belts with very fine grits. Skews get ground to 3600 grit. Bowl gouges are perfectly fine with 160grit.

 

[Randy Heinemann]

Actually I don't use CBN wheels. I sharpen with a diamond wheel on my Tormek - mostly 600 grit. Since I mostly sharpen gouges, sharpening takes about 30 seconds and I sometimes sharpen during a bowl, but the edge seems to last a long time on my powdered steel Crown gouges, so most of the time it isn't necessary to resharpen until I shear scrape and cleaning up tearout. I also have a 300 grit wheel which, in the end, I think was a waste of money since I really haven't used it more than 2 times in about 2 years.

 

[Richard Coers]

Never enough options for the number of possible combinations of ways to sharpen. Most of my techniques never win the popularity poll.

 

[robo hippy]

Well, I do hone my skew chisels. Still figuring them out. I have found that stropping the edge does not bring it back, so I go back to the grinding wheel or a hand hone, then strop. I have heard some say that they never strop the skew. For me, it made a major difference. Using honing/polishing type stones, up to 8000 grit, it still leaves a burr, no matter how light my hand pressure is. I currently have 3 stropping grits, up to 16000. Still don't know if going that high makes as much of a difference as the species of wood does. I remember John Lucas's experiment with ebony and he said he couldn't really tell any difference.

For bowl gouges, I go from 180 to 600 grit, depending on which grinder is closest. The only times the finer grit wheels make a difference seems to be if the wood is punky, and with big leaf maple, that is common. I never bother to hone the edges on my bowl gouges. For what I do, it doesn't seem to make any noticeable difference. Perhaps I should try it on some myrtle I have been turning. Sharpness has been a non factor with this log, it always seems to be quite rough as in 80 grit sanding to start. NRS, shear scrape with grinder burr or burnished burr, 80, 180, 600 grit seems to make no difference. I have yet to hone or strop the burr off of my bowl gouges, but maybe it will help with this particular log.

I own one of Odie's bowls, a black and white ebony one he posted up a year or three back. His work is on a whole different level. You have to see it, pictures do not do it justice....

Oh, maybe included here could also be burnished burr or grinder burr for NRSs.

robo hippy

 

[Robert Santore]

By honing, do you mean taking the burr off the top, or refining the surface you've just ground?

 

[William Rogers]

By honing, do you mean taking the burr off the top, or refining the surface you've just ground?

Good question. Mostly refining surface just ground or in between trips to grinder.

 

[Lennart Delin]

I usually use the gouge straight from 180 grit CBN, with a very quick honing on the inside only, only a couple of strokes with a diamond. A test on fast grown spruce, turned with the wing:
1 Straight from the grinder CBN 180 grit
2 Honed on inside
3 Honed inside and outside

 

[odie]

The real test will be seasoned bone dry hardwoods with high ratings of Janka hardness......like these on
the shelves above the fan.

-----odie-----

 

[William Rogers]

@odie Just curious if you will eventually go not CBN wheels. And if you care to share why you think a friable wheel is better. Been a while since I honed a tool of the friable wheels, but I am fairly certain it is much easier to hone a gouge when sharpened using a CBN wheel. You definitely remove less material verses a friable wheel.

 

[robo hippy]

Honing is one thing, and stropping is another. Honing, or maybe polishing, still leaves a burr, even if it is very small. I find burrs on my bench chisels and plane irons even on stones up to 16000 grit. The stropping pastes remove the burr. The honing plates do not remove the burr.

robo hippy

 

[Robert Santore]

Good question. Mostly refining surface just ground or in between trips to grinder.

for gouges I have been taking the burr off the top after grinding. I tried honing as a means to put off a trip to the grinder, but I find that I can put a fresh edge on the grinder now in less time than it takes to hone. Based on what people have said above it sounds like honing may give you a better cut, and I'd certainly be willing to try that again. I am a fairly new turner, still learning a lot and am definitely not settled yet on anything in particular.

I had read that some prefer toothy edges on gouges, and production folks seem to take a quick grind and get back to work, so didn't really think honing the ground surface was necessary.

a few quick notes about other tools
scrapers - I've been honing the burr off before grinding so the new burr goes on a clean edge, based on what I've seen Richard Raffan do
skews - I hone after grinding to remove the burr (unless I am going to use it like a NRS).

Like I said, still learning a lot and open to ideas. I really like the type of comparison @Lennart Delin did above. I'm also interested to hear @robo hippy say he sees a big difference on skews when he strops. Might give that a try.

 

[odie]

@odie Just curious if you will eventually go not CBN wheels. And if you care to share why you think a friable wheel is better. Been a while since I honed a tool of the friable wheels, but I am fairly certain it is much easier to hone a gouge when sharpened using a CBN wheel. You definitely remove less material verses a friable wheel.

Hello Bill......

I'm not planning to go to the cbn wheels anytime soon.....but, who knows what's in store for me to evolve to! I don't necessarily feel using a friable wheel is better than using a cbn.....but, it's certainly as good, IMHO. I have the original Norton SG wheels, and they do last forever, it seems. These have been in use for at least a decade! When they were phased out for the new type SG wheels, I bought a couple more of the old style SG 80gt wheels.....which are still new in the box! From my POV, the grinder has no other purpose than to remove metal, while the cutting edge itself is entirely honed.

All of this, of course, is a matter of preference, and I'm not saying the way I sharpen and hone is what's best for anyone else, but myself. I freely give my own thoughts and conclusions......and, leave it up to anyone else to take it or leave it. (What I personally think is most other turners are inclined to "leave it" for most of the ways that I do things!.....I feel it's all a matter of results, and I feel satisfied with my methods of achieving the results I've been getting as of late.)

It's interesting that you feel honing would be different, if it's done to a surface that's prepped by a cbn wheel, as opposed to a friable wheel. There is a micro bevel that separates the very tip of the edge from the bevel, and the two things aren't connected at all, so I'm having a hard time to grasp the concept that there is a difference. Maybe you can explain that to me a little more succinctly, so I can better understand your own POV.....?

-----odie-----

 

[Lennart Delin]

It's interesting that you feel honing would be different, if it's done to a surface that's prepped by a cbn wheel, as opposed to a friable wheel. There is a micro bevel that separates the very tip of the edge from the bevel, and the two things aren't connected at all, so I'm having a hard time to grasp the concept that there is a difference. Maybe you can explain that to me a little more succinctly, so I can better understand your own POV.....?

-----odie-----

I did a comparison of the grind from different wheels and there are no major difference of the edges. CBN 180 grit, aluminum oxide 120 grit, Tormek aluminum oxide 220 grit. Old carbon steel chisel.

Otherwise the main difference has been stated many times:
CBN does not need to be dressed and keeps the same diameter, so you never have to reset tool rests or jigs due to wear of the wheel.
CBN heats up the steel much less, though not significant for HSS.

 

[odie]

I did a comparison of the grind from different wheels and there are no major difference of the edges. CBN 180 grit, aluminum oxide 120 grit, Tormek aluminum oxide 220 grit. Old carbon steel chisel.

Otherwise the main difference has been stated many times:
CBN does not need to be dressed and keeps the same diameter, so you never have to reset tool rests or jigs due to wear of the wheel.
CBN heats up the steel much less, though not significant for HSS.

View attachment 48247

Hello Lennart.....

The question that arose concerning William Roger's statements, was whether the hand-honed edge was different as a result of the type of wheel used for creating the bevel. It wasn't a matter of comparing the edges created by different types of wheels.

Of note in your photos is the obvious single direction of the grinding markings on the edges created by the CBN, and Aluminum Oxide wheels, and those on the Tormek are much less apparent. This is consistent with previous observations noted. It is also an indication that multiple directions during a honing process eliminate these grinding marks on the very tip of the edge, and directly effect the efficiency of the cutting edge's ability to produce a cleanly executed cut.

Thanks for making the effort to create and post those photos......they are significant and helpful.

-----odie-----

 

[Monty Ivy]

A difference to consider...

A grinder wheel of any type creates a small hollow grind that follows the radius of the wheel. The RS Pro-edge provides a flat grind with no hollow. This is very advantageous on certain tool types, scrapers, skews, spindle gouges, bench chisels, and plane knives. I don't think it makes much difference for bowl gouges given the rotating jig setup common across both systems.

My Tormek T-8 setup has been retired and sits on a shelf these days.

 

[William Rogers]

@odie It has been a long time since I used a friable wheel and maybe other factors were much more a contributor. I now use a CBN pocket hone instead of the eze diamond hone and I may not have been the best at keeping my wheel properly dressed. I do like the CBN pocket hone 600/1000 grit better and the CBN wheel better as I don’t have to dress it.

 

[Doug Freeman]

A difference to consider...

A grinder wheel of any type creates a small hollow grind that follows the radius of the wheel. The RS Pro-edge provides a flat grind with no hollow. This is very advantageous on certain tool types, scrapers, skews, spindle gouges, bench chisels, and plane knives. I don't think it makes much difference for bowl gouges given the rotating jig setup common across both systems.

My Tormek T-8 setup has been retired and sits on a shelf these days.

Please elaborate on why you think a flat grind is better than a hollow grind, Monty.

 

[Monty Ivy]

Please elaborate on why you think a flat grind is better than a hollow grind, Monty.

Mainly it's because it more closely matches the form of the original factory edge. It won't take a scoop out of the face of a chisel or skew.

 

[William Rogers]

I agree with Monty. An 8” wheel doesn’t produce much of a hollow grind, but there is some. I have the ProEdge and like the grind it does for my skews, parting tools, roughing gouges, and scrapers. Very easy to set to any angle and you have a large variety of grit choices, plus my skews still look like skews. I don t Use the ProEdge for other gouges as the protrusion is quite a bit. I use the Hannes Vector jig and doubt I would ever use anything else. I have a friend that uses the Wolverine jig and so far he has given me 6 bowl/ detail gouges either Thompson or Dway that are too short for him to sharpen. I’ll get quite a bit of use from those and doubt I will ever need to buy bowl, spindle, or detail gouges again .

 

[odie]

@odie It has been a long time since I used a friable wheel and maybe other factors were much more a contributor. I now use a CBN pocket hone instead of the eze diamond hone and I may not have been the best at keeping my wheel properly dressed. I do like the CBN pocket hone 600/1000 grit better and the CBN wheel better as I don’t have to dress it.

A CBN pocket hone is something I might like to give a try......where are they available?

-----odie-----

 

[Monty Ivy]

A CBN pocket hone is something I might like to give a try......where are they available?

-----odie-----

I think woodturnerswonders has them.

 

[William Rogers]

A CBN pocket hone is something I might like to give a try......where are they available?

-----odie-----

The are available at WoodTurners Wonders. The flat one is $13.95, but the tear drop is $75. right now I am using leather with honing compound, however I still believe in Santa and hope he thinks I have been good and bring me the tear drop CBN.

 

[odie]

The are available at WoodTurners Wonders. The flat one is $13.95, but the tear drop is $75. right now I am using leather with honing compound, however I still believe in Santa and hope he thinks I have been good and bring me the tear drop CBN.

Can I assume the CBN surface is not as hard as a diamond surface?

edit: Not sure if that's the right question. ^^^^

Maybe I should ask if CBN cuts steel better than a diamond will.....?

-----odie-----

 

[William Rogers]

@odie This is the sales pitch from Woodturners Wonders

Introducing WoodTurners Wonders newest hone. This hone has been requested over and over again by our customers. It's now finally available at a price below similar diamond hones–and we all know by now CBN is far superior for honing hard tool steel than diamonds–any day and twice on Sunday!


I guess the HaHa was because you don’t think I have been good!

 

[odie]

@odie This is the sales pitch from Woodturners Wonders

Introducing WoodTurners Wonders newest hone. This hone has been requested over and over again by our customers. It's now finally available at a price below similar diamond hones–and we all know by now CBN is far superior for honing hard tool steel than diamonds–any day and twice on Sunday!


I guess the HaHa was because you don’t think I have been good!

Well, we all know about "sales pitches"......

I suppose the only way to verify that is to buy one.

edit: Only you, the man upstairs, and Santa will know for sure.......

 

[robo hippy]

Well, check out Sharpening supplies.com. More things than you ever knew existed for sharpening anything. That being said, I would prefer diamond hones and cards for touchups if I did that. On the skew, it is worth it, but you still should strop. As for the difference between diamond and CBN, the diamond is harder, but on standard grinders, the speed is too much, and the diamonds degrade quickly with any heat build up. This is why they work on the Tormek, but not on slow speed grinders. The Tradesman grinder set up from Canada has a variable speed grinder, and you can get CBN or diamond wheels for it. I believe they started out for sharpening the CNC carbide bits. CBN can touch up carbide, but it really shortens the life of a CBN wheel. As for which cuts faster, I would expect comparable grits to cut equally well. The thing is that the CBN will eventually wear out. The diamond should pretty much outlast all of us. I had some old DMT stones, like 30 years old, that pretty much didn't cut any more. Put some trend lapping fluid on them and they really came back to life. I now use auto glass cleaner on my lapping plates. There is no ammonia in it, which can bother the plating of the abrasives. Plain water also helps keep them clean. I think that most of the time, what keeps them from cutting well is that they get gunked up. Really true on my CBN wheels when I am turning sloppy wet madrone.

robo hippy

 

[Doug Freeman]

From Eagle Superabrasives (and other sites as well):

"Diamond is composed of pure carbon and is produced under high heat and pressure. When Diamond is used to grind hardened steel it causes a chemical reaction and essentially begins to form graphite and lose it strength.

So what makes CBN better for working with hardened steels? CBN is not composed of carbon atoms, instead it is formed with boron and nitride under pressure and heat. Grinding hardened steels produces high temperatures, CBN has a great thermal conductivity, keeping it cool under extreme heat."

Please note it says grinding, not hand honing. I can't come up with a good reason to replace diamond hones with cbn, but if one needs a new hone, and cbn is cheaper, I see no reason not to get the cbn. My diamond hones have held up for many years.

 

[Gerald Lawrence]

Please elaborate on why you think a flat grind is better than a hollow grind, Monty.

I think he is referring to the skew. It is easier to learn with a flat grind rather than hollow grind. Info came to me via Capt Eddie and I tried but it is a pain to sharpen a skew that way and I learned to use the hollow grind. Oh the flat grind did work easier.

I have two CBN cards 180-220 and 320-600. The do work well. I have only used diamond handle hones and cannot campare.

 

[William Rogers]

I have only had inexpensive diamond hones and seem to wear out quickly. I would think the expensive diamond hones would last much longer. The CBN hone I use has lasted for 2+ years and is still working well, I still want to get the CBN tear drop hone. It may be a preference, but CBN seems to work well for honing.



@Doug Freeman Interesting post. Good information.

Regarding flat vs hollow grind I prefer flat grind my skews. Sharpening skews on the ProEdge is easy and they look like they are factory ground.

 

[Randy Heinemann]

From Eagle Superabrasives (and other sites as well):

"Diamond is composed of pure carbon and is produced under high heat and pressure. When Diamond is used to grind hardened steel it causes a chemical reaction and essentially begins to form graphite and lose it strength.

So what makes CBN better for working with hardened steels? CBN is not composed of carbon atoms, instead it is formed with boron and nitride under pressure and heat. Grinding hardened steels produces high temperatures, CBN has a great thermal conductivity, keeping it cool under extreme heat."

Please note it says grinding, not hand honing. I can't come up with a good reason to replace diamond hones with cbn, but if one needs a new hone, and cbn is cheaper, I see no reason not to get the cbn. My diamond hones have held up for many years.

I've used diamond wheels from Tormek on my Tormek for a couple of years. I can't say that there has been any degradation of the length of time a sharpening lasts on my Crown PRO-PM gouges. While I can say that I don't know what powder metallurgy really means, I don know that these gouges get very sharp and stay sharp longer than other HSS gouges I have used and other HSS turning tools I own. I have sharpened them only on the Tormek diamond wheel (mostly 600 grit). I suppose it's possible that the degradation occurs over a very long period or with heavier use than I put these tools to, but they continue to perform as they did when I bought them. I checked on Eagle Abrasives site. It appears they are a commercial industrial supplier of all kinds of grinde wheels. I'm sure they are a good company, but I wonder if their recommendations apply to a low speed grinder like the Tormek (which I doubt is manufactured for an industrial environment) and for the lower intensity use of grinding wheels in the home shop. I don't

 

[Randy Heinemann]

I followed up with Sharpening Supplies customer support. I have found that their support staff always gives reasonable and accurate answers. Since they sell all kinds of sharpening wheels and systems, including both CBN and diamond wheels, they don't appear to have any reason to be biased toward one type of wheel or another. The answer seems to be close to what I suspected; namely that, with standard grinders there is a certain amount of heat build up, even with lower speed grinders (1750 rpms). This heat seems to be what causes the reaction with the diamond surface and HSS tools. Because of the slow rpm's of a Tormek (about 90 rpm's I think) and continuous water cooling, there is no heat build-up and, therefore, no reaction between the diamond surface of the wheel and the HSS. It appears to be the reason that Tormek does not offer CBN and went with diamond instead. My experience to date doesn't indicate any degradation of the tools. Rather the result is an extremely sharp tool and, in the case of the powdered steel Crown tools, a very long lasting edge. If I were to buy a standard low speed grinder, I would certainly buy at least 1 CBN wheel rather than diamond.

 

[Mark Jundanian]

I seem to recall that WoodTurners Wonders offered a CBN wheel for Tormeks.

 

[Robert Santore]

I seem to recall that WoodTurners Wonders offered a CBN wheel for Tormeks.

They do. I just recently swallowed hard and bought one (they ain't cheap, but neither are Tormek diamond wheels) and am really happy with it. I find it really cuts down on the time needed to freshen a tool compared to the aluminum oxide water stone.

 

[Randy Heinemann]

I seem to recall that WoodTurners Wonders offered a CBN wheel for Tormeks.

I just checked and they do. However, the price is about the same as Tormek's diamond wheels. Actually, the point I was making was that was no reason to be concerned about using diamond wheels on a Tormek machine because of speed and water cooling; no heat. That is the reason that Tormek does not make a CBN wheel for their machines - there is no reason to . . .