CBN.....an alternative point of view.

[odie]

I thought about posting to the CBN thread, but decided it would be more appropriate to comment elsewhere.

I hone my cutting tools, and I can say without question that it does require a long term commitment to learn how to acquire a perfect honed cutting edge. Of course, there are many more things in the equation.....but the basic reality is......the sharper the tool, the better the cut. (....and, just because one has a sharp tool, it doesn't mean the human element, other tooling and variables aren't involved.) I've found that the sharpest edge is honed on both sides of the edge, and I use 400-600 grit diamond hones to accomplish that. I've heard others say: "the edge just doesn't last very long......and, I'll agree with that 100%! The trick is to hone often, even to the point where it's disappointing how often it requires when doing your final cuts prior to sanding. When you start sanding regularly at 320, 400, and even 600, you'll be glad you did. Face it, sanding removes wood unevenly, depending on the grain structure.....long grain, end grain, irregular grain pattern, between annular rings, etc. When the wood is removed unevenly, the geometry becomes more distorted than when little sanding is required directly from the tool surface. The "tool surface" is as close to perfect geometry as can be had on a wood lathe.

For my purposes, the grinder wheel, whether it's CBN, or a matrix bound stone, is basically irrelevant to the cutting edge possible. The grind wheel has no other purpose, than to remove tool steel in basic preparation for producing a profile capable of being honed to a more perfect edge.

I don't know the actual numbers, but my guess is the turners who bring cutting tools directly from the grinder to the lathe, far outnumber those who hone......and those who meticulously hone are a small number compared to those who do it minimally.

Of course, the exception to all this is scrapers.....and there, I do as most everyone else does. I use the burr edge directly from the grind wheel.

ko

 

[hockenbery]

. Of course, the exception to all this is scrapers.....and there, I do as most everyone else does. I use the burr edge directly from the grind wheel. ko

I agree with you that few bowl and hollow form turners hone their bowl gouges.
I don't. It just is not worth the effort.

However most of those turners probably use a hone on scrapers.
Folks don't hone scrapers but many use a hone to remove the burr before sharpening if they use the burr from the wheel and a whole lot remove the burr after sharpening and strike a fresh burr with a stone or diamond hone. This gives a finer more consistent burr and thus a cleaner surface.

I can strike a new burr 4-5 times before going back to the grinder often enough to complete the job.
Burrs last a very short time and striking a new with a hone is quick and easy.

Keep in mind there is significant difference in honing for spindle work.
Just about every spindle turner hones. The skew must be honed to be useful.

Al

 

[john lucas]

I've been playing with sharpening a lot in the last 5 years or so. Woodturning magazine had an article years ago that showed how a sharper tool will hold an edge longer than a semi sharp tool. The theory is that an edge has to wear down to a certain point to be considered dull. a tool that is sharpened to a more refined edge (think about the top of an inverted V vs an inverted U) takes longer to wear down to the same degree of dullness (if thats a word) I have been sharpening some tools with 400 or 600 grit sanding belt and some with a Tormek Grinder which is supposed to be roughly 1000 grit. I do like the way they cut. Can't really tell if they hold an edge longer. That's like trying to tell if the Particle metal tools hold an edge longer than the HSS. I think they do but I don't really have scientific evidence to prove it.

There comes a point however such as in roughing bowls that I think it's waste of time to sharpen beyond a certain level. Straight off the grinder works perfectly fine for most of that. If I get tearout in those troublesome spots then I'll usually hit it with a hone or go to one of my finer grit sharpening tools.

 

[Bill Boehme]

Four topics guaranteed to start a war ....

... politics, religion, sharpening, and sanding. Despite that, thanks for starting this discussion. I'm sure that there is a diversity of views on what is "sharp". A recent issue of American Woodturner (June 2014, page 18) had an article on sharpening by Terry Martin. I felt that my opinion was somewhat validated by what he wrote. I wouldn't be too surprised if others may have gotten their hackles up.

... I hone my cutting tools, and I can say without question that it does require a long term commitment to learn how to acquire a perfect honed cutting edge. Of course, there are many more things in the equation.....but the basic reality is......the sharper the tool, the better the cut....

It is somewhat interesting that on one hand we stress to newbies the great importance of getting tools sharp ... sharper than what they think is sharp in many cases ... and on the other hand there's a diversity of opinion about the meaning of sharp. Topics like "what is sharp enough" and "what is too sharp" occur whenever two or more woodturners get together.

... I've heard others say: "the edge just doesn't last very long....

But, we both know that it lasts longer than an edge that isn't as sharp to begin with. And, my opinion is that a very sharp edge lasts much longer than some think it does ... I believe that edge wear is not a linear function, but a continuously accelerating one because friction increases the wear rate as the edge gets duller. If we assume that a very sharp edge with a smooth bevel has less friction than a rough bevel with a less sharp edge then it seems reasonable that the wear rate will be less. I should point out that sharper edge doesn't mean more acute edge angle when comparing sharpening methods such as honing and not honing.

... I don't know the actual numbers, but my guess is the turners who bring cutting tools directly from the grinder to the lathe, far outnumber those who hone......and those who meticulously hone are a small number compared to those who do it minimally....

From my dozen year perspective of meeting and talking to hundreds of turners, I would guess that the figure is well above 90% who go straight from the dry grinder to the wood ... not that there's anything wrong with that.

I don't always hone, but my justification for not honing is that when my Tormek wet grinder stone is graded smooth, it results in a smoothness comparable to honing. When it really matters, I'll go the extra step and use the leather honing wheel.

... Of course, the exception to all this is scrapers.....and there, I do as most everyone else does. I use the burr edge directly from the grind wheel....

This means that I must be the 6σ outlier. I remove the weak burr created by the grinder with a hone and then use a burnishing tool to put a more robust burr on the tool. The burnishing tool is an extremely hard and polished steel rod that is oval shaped in cross section. I originally bought it when I did flat woodworking to put a burr on cabinet scrapers. The nice thing is that it only takes a few extra seconds to do this and the result is a scraper than can make very smooth cuts in addition to scraping. Also, this type of burr is durable. Learning to raise a burr takes some practice. The most common mistake when first learning is applying too much pressure and rolling the burr over into a curl.

... Face it, sanding removes wood unevenly, depending on the grain structure.....long grain, end grain, irregular grain pattern, between annular rings, etc. When the wood is removed unevenly, the geometry becomes more distorted than when little sanding is required directly from the tool surface. The "tool surface" is as close to perfect geometry as can be had on a wood lathe....

We should also add that heavy sanding kills all crisp details that are especially important features in spindles and finials (or anything else that has crisp details for that matter). Would you believe that I can start sanding with 1000 grit paper?

 

[odie]

The theory is that an edge has to wear down to a certain point to be considered dull. a tool that is sharpened to a more refined edge (think about the top of an inverted V vs an inverted U) takes longer to wear down to the same degree of dullness .

Exactly, John......

The thing to grasp is individual turners don't agree on what is dull, and when to resharpen. (Not to mention they don't agree what is sharp, either! ) Those things are variables, depending on the results, and how much finish sanding is required. Different pieces of wood and species will be different, as well. Handling techniques will also vary between turners.....you might take the same piece of wood, with the same tool, mounted on the same lathe, and end up with a different surface quality than myself, or another turner.

Can't really tell if they hold an edge longer.

One sure-fire way to know for sure, is to observe how well intersecting planes meet. If it's a crisp clean corner, then you have not altered the geometry to a significant degree. Another way to tell, is to do some detail grooves on your turning. If the detail grooves are consistent in depth and width.....there again, the geometry hasn't been changed to a significant degree. If you are sharpening and honing more frequently, in order to maintain the objectives of maintaining geometric integrity, then the edge isn't lasting as long. If a turner is satisfied to start sanding at a coarser grit, then the bets are off! Ha!

That's like trying to tell if the Particle metal tools hold an edge longer than the HSS. I think they do but I don't really have scientific evidence to prove it.

I only have a couple particle metal tools, and I honestly can't tell the difference. Personally, I'm a big fan of M2 HHS. I know I hone and sharpen more often, but this old trusted HHS is such an easy re-hone+grind, that I'll probably never go to anything harder. IMHO, M2 is the perfect balance between edge holding abilities, and ease of sharpening.

There comes a point however such as in roughing bowls that I think it's waste of time to sharpen beyond a certain level. Straight off the grinder works perfectly fine for most of that. If I get tearout in those troublesome spots then I'll usually hit it with a hone or go to one of my finer grit sharpening tools.

I agree with that!.......although, I do a quick once-over with the hone while roughing. I normally don't worry too much about the fineness of the cut while roughing, but again, a cleaner cut is always preferable.....I don't let it get too out of hand! The boundaries of what I consider acceptable depends on what my intent for final shape is, elimination of bad wood, best artistic grain, and a host of other things. These boundaries are much more critical that I felt they were at other times in my turning evolution.

 

[Raul McCai]

Remember when all the cool kids had waterstones and would spend hours flattening them, kept them in special built benches with water always around? The mess? Ohh the mess. And winter. Can't let 'em freeze.
I managed to skip right on past the whole water stone thing.

I do like diamond. It's fast.

But - - - - -

There was a time when I laughed at the those guys with their mirror polished edges.



Then one day I tried it. I'd gotten a quart of 3M aluminum oxide auto paint polish for black paints. So I squirted some on a length of scrap wood - - ran my hand chisel along it for a few strokes until I obtained a mirror polish at the edge.
Then tried the chisel.

I was blown away.
Now I'm a fan of highly refined edges.

It doesn't matter how you get there.

 

[Tom Cadwalader]

Burnishing question

"The burnishing tool is an extremely hard and polished steel rod that is oval shaped in cross section. I originally bought it when I did flat woodworking to put a burr on cabinet scrapers. The nice thing is that it only takes a few extra seconds to do this and the result is a scraper than can make very smooth cuts in addition to scraping. Also, this type of burr is durable. Learning to raise a burr takes some practice. The most common mistake when first learning is applying too much pressure and rolling the burr over into a curl."

Where would one find a good source for learning to use a burnishing tool?

 

[odie]

"The burnishing tool is an extremely hard and polished steel rod that is oval shaped in cross section. I originally bought it when I did flat woodworking to put a burr on cabinet scrapers. The nice thing is that it only takes a few extra seconds to do this and the result is a scraper than can make very smooth cuts in addition to scraping. Also, this type of burr is durable. Learning to raise a burr takes some practice. The most common mistake when first learning is applying too much pressure and rolling the burr over into a curl."

Where would one find a good source for learning to use a burnishing tool?

Hello Tom.......

I'd also be interested in seeing some information/video on this subject.

I've had one of the Veritas carbide burnishers for many years, and from time to time, I take it out and give it another try. I haven't had much success in improving my scraper burrs with it. It may raise the burr somewhat, but I'm not seeing any improvement in the quality of the surface it leaves on the wood.

One thing I've found that vastly improves the burr straight from the grinder, is to use a very slow sweep of the scraper against the wheel. It helps a lot to make this sweep at the same speed as it progresses through the arc. These things tend to make a better, or more prominent burr that performs well......or, for my purposes it does.

As always, I'm interested in improving through experimentation and comparison of results, as an ongoing effort......and, as usual, the results are the only thing that counts! It's not about how good the tool looks at all......it's all about what you can do with it!

ko

 

[hockenbery]

The Veritas burnisher is one such tool.
lee valley carries as do many woodturning supply companies such as CSUSA, Packard, HIGLAND HARDWARE ETC...

Here is a description I its use
http://www.leevalley.com/us/shopping/TechInfo.aspx?p=41594

I don't have one but have used one several times. The burr changes the angle a bit and can be more aggressive but leaves a nice surface on the wood.

Al

 

[Tom Cadwalader]

Thanks but.....

The link was helpful........ For someone who has never used one or seen one....... I need to start with the 101 version.

 

[odie]

Question:

When raising the burr on a scraper, and the cutting tip of that burr is unaltered, but the height of the burr is increased......how will that make it cut any better if the cutting edge is the same either way?

Possibly a raised burr may be more useful for heavy cuts, which I don't do. All my heavy stock removal is done with gouges, and all my scraper work is done with a light shearing cut.

Looking for comments from those who have actual sustained experience with this, who can shed some light on the advantages, if that's what they perceive them to be......

ko

 

[odie]

This means that I must be the 6σ outlier. I remove the weak burr created by the grinder with a hone and then use a burnishing tool to put a more robust burr on the tool. The burnishing tool is an extremely hard and polished steel rod that is oval shaped in cross section. I originally bought it when I did flat woodworking to put a burr on cabinet scrapers. The nice thing is that it only takes a few extra seconds to do this and the result is a scraper than can make very smooth cuts in addition to scraping. Also, this type of burr is durable. Learning to raise a burr takes some practice. The most common mistake when first learning is applying too much pressure and rolling the burr over into a curl.

I think I'm seeing through the fog a little here, Bill!

What were discussing is your removing the burr left by the grind wheel, and I'm keeping the burr, and raising that. Also, since you mentioned that raising the burr takes some practice to learn, I wouldn't know from my limited experience with it. Also, I'd have to say the burr raised on my 80grit Norton SG wheels is a very decent, and very useful burr. There also, it takes some practice to do it well. I mentioned some of the key pointers in a previous post.

Maybe since I haven't been removing the burr left from grinding, and trying to raise that.....it represents the differences between how you see this, and how I see it. It could be that I've been spinning my wheels trying to raise a burr that's already there, rather than starting with a surface that had the burr removed.

I plan to be back in the shop tomorrow afternoon, and I'll attempt another shot at the Veritas carbide burnisher......but, after the burr from the grind wheel is removed. I'm going to do a little experimenting with a raised burr on the Veritas, compared to the burr raised on the SG wheel.....all on the same piece of wood. That ought to make the difference a little more clearly defined.

As I always say......results are the ONLY thing that matters.....and, I'm feeling very satisfied with the results I've been getting with the grinder burr. If I can improve on that, it is my objective to find a way to do it.

We should also add that heavy sanding kills all crisp details that are especially important features in spindles and finials (or anything else that has crisp details for that matter). Would you believe that I can start sanding with 1000 grit paper?

Yes, very true about the "heavy sanding" kills details. Not having to sand much.....that's the key to preserving the geometry, whether it's bowl turning, or spindle turning. Yes, I can believe a skillfully executed spindle turning can start sanding at a much higher grit than I can manage with my bowl turning......the difference, as you are aware of.....is the grain orientation differences between the two processes.

ko

edit: After re-reading the link Al Hockenbery gave us in post #9, I have to ask if you're using your hand burnisher to raise a burr on carbon steel, or HSS scrapers?

The burnisher was designed for use with high-speed steel scrapers. It is possible to roll a hook on carbon steel scrapers with a hand burnisher, but with high-speed steel you need a great deal of force and I have found that the fulcrum pin gives me the stability I need to really lean into my work.

 

[Bill Boehme]

"The burnishing tool is an extremely hard and polished steel rod that is oval shaped in cross section. I originally bought it when I did flat woodworking to put a burr on cabinet scrapers. The nice thing is that it only takes a few extra seconds to do this and the result is a scraper than can make very smooth cuts in addition to scraping. Also, this type of burr is durable. Learning to raise a burr takes some practice. The most common mistake when first learning is applying too much pressure and rolling the burr over into a curl."

Where would one find a good source for learning to use a burnishing tool?

I don't know. I've read descriptions in Fine Woodworking, seen demonstrations using them on cabinet scrapers at woodworking shows, and had a one-on-one with Alan Lacer where he showed using it on a woodturning scraper, but the key thing that is hard to convey would be how much hand pressure to apply when using the tool to put a burr on a scraper.

I bought my burnishing tool many years ago at the local hardware store back when the owner was a serious woodworker. Now, a big corporation owns the store so they no longer have neat stuff. It was made in "West" Germany which ought to give you a hint about how old it is.

It doesn't take much hand pressure. I think that the natural tendency is to apply too much pressure which results in rolling the burr over too far so that it is useless or breaks off.

I start by sharpening the scraper on my Tormek so that it has a very clean bevel and a sharp edge with a very tiny burr. I remove this burr by placing the top of the tool flat against the side of the Tormek wheel for a couple seconds to remove the tiny burr. Note that you can also do this with a diamond hone. Make sure that the hone is flat so that the edge doesn't get rounded over.

Next I use the steel on the top of the tool angled slightly towards the edge to make a very small forward facing burr. This step may be skipped.

Next, I put the steel against the bevel and roll the burr upwards.

Then, I angle the steel about ten degrees or so towards the edge and with slightly more pressure I pull a heavier burr. You should very easily be able to feel it with your fingernail running on the back side of the burr. Just don't slide a fingertip along the burr.

Try it out on a piece of wood. If the burr is rolled over too far then the results will be like scraping with a dull tool. If the burr is too small then the results will be mostly dust and a few small shavings ... not very exciting. A perfect bur will enable you to literally turn a entire bowl out of green wood and get beautiful shavings. It took me a lot of tries before I finally got it right. I think that Alan Lacer helped me the most because of the one-on-one situation.

Here is an article in Popular Woodworking.

Here is another good description of how to put a burr on a cabinet scraper.

Here is an article on sharpening scrapers by Alan Lacer that appeared in American Woodturner.

And, one more.

 

[john lucas]

I've wondering if there is a difference in the burr on a cabinet scraper vs a turning tool. On a cabinet scraper you first square up all edges and ideally hone them so they form a clean sharp 90 degree angle. Then you raise the burr with the steel (I believe they call it a ticketer but don't know how it's spelled). then you shape the burr by moving the steel at an angle. Your taking fairly large shavings with this tool. On turning tools we tend to simply polish the burr off the edge ,which can vary from about 45 degrees for John Jordan's shear scraper or Stewart Batty's negative rake scraper, up to about 75 or 80 degrees for old style scrapers. If you use the ceramic hone that John sells you probably do get a more polished edge before you start. I tend to refresh my edges frequently so I can't really say that an edge off the grinder lasts longer or shorter because I tend to use it for just a pass or so and then either regrind or hit the edge with the stone depending on which tool I have in my hand. Since we are sticking it into rotating wood we are removing very little per pass. for a shear scrape. Since I'm only using scrapers as a shear scrape on troubled areas as a final touch up I don't need the burr to last all that long.

 

[hockenbery]

A few folks use cabinet scrapers on turning.
Clay Foster has been using a cabinet scraper for many years on hollow forms.
Works really well for Clay.
I have tried it but never felt comfortable with it.
90% of my scraping is done with a bowl gouge in shear scraping mode.

I use shear scraping to remove the small tool marks left from the bowl gouge.
If I'm doing a square edge piece or a platter I shear scrap with a square edge scraper with a slight radius like Al Stirt uses.
This tool can be used with the handle close to level and works really well against a bead or a transition.

 

[odie]

I think the real question here, is whether a raised burr is, or can be an improvement over a ground burr. Obviously, a turner is necessarily going to have additional effort to acquire the raised burr......but, will there be an improvement in surface quality? If there is, then it will be worth the extra effort. John's right about how quick it is to refresh the ground burr. That's a great benefit to a turner......and, the results capable with the ground burr for finishing cuts just prior to sanding, is a pretty high standard to best.

Is there a difference between the raised burrs left by the burnishing tool vs the Veritas? That question I won't be able to address, since the Veritas is the only device I have for raising a burr. I will be able to compare the quality of the cut for either of these two types of burrs, by the methods I am capable of producing them.....ground burr left by the SG-80 wheel, or raised burr with the Veritas tool. I'm still going to perform my little "lab experiment" this afternoon. If the raised burr that can be had by removing the ground burr first, appears to "raise the bar" over what I can achieve with a ground burr, I will incorporate it into my methods of achieving the best possible surface, prior to sanding.......

I guess we can chalk it up to my own lack of understanding that I never realized the raised burr was AFTER removing the burr left by the grind wheel.....

ko

 

[Bill Boehme]

I think the real question here, is whether a raised burr is, or can be an improvement over a ground burr. Obviously, a turner is necessarily going to have additional effort to acquire the raised burr......but, will there be an improvement in surface quality? If there is, then it will be worth the extra effort. John's right about how quick it is to refresh the ground burr. That's a great benefit to a turner......and, the results capable with the ground burr for finishing cuts just prior to sanding, is a pretty high standard to best.

From all that I have read about burrs created by dry grinding is that they are not very durable smeared and crumbly metal that has a rather rather ragged appearance when viewed under magnification. I have also read that the burr created by a CBN wheel is smaller and weaker than that created by a matrix wheel because of the lower heat ... sounds reasonable.

Viewed under magnification, the burr created using a burnishing tool has a smoother and continuous solid appearance with an edge that appears to be sharper. I don't have much (hardly any) experience using a burr created with a dry grinder since I almost exclusively use my Tormek for sharpening scrapers and then make the burr with the burnishing tool. I like the way that it works, but occasionally I don't get a good burr and have to start over.

... Is there a difference between the raised burrs left by the burnishing tool vs the Veritas?...

The Veritas tool that you have IS a burnishing tool. The only difference is instead of being a long rod with a handle, it is a short tapered piece that fits into their fixture that screws to the bench top or wherever you fasten it. I suppose that Veritas believes that using their fixture help you make a consistent burr.

 

[Tom Cadwalader]

Very helpfull

I don't know. I've read descriptions in Fine Woodworking, seen demonstrations using them on cabinet scrapers at woodworking shows, and had a one-on-one with Alan Lacer where he showed using it on a woodturning scraper, but the key thing that is hard to convey would be how much hand pressure to apply when using the tool to put a burr on a scraper.

I bought my burnishing tool many years ago at the local hardware store back when the owner was a serious woodworker. Now, a big corporation owns the store so they no longer have neat stuff. It was made in "West" Germany which ought to give you a hint about how old it is.

It doesn't take much hand pressure. I think that the natural tendency is to apply too much pressure which results in rolling the burr over too far so that it is useless or breaks off.

I start by sharpening the scraper on my Tormek so that it has a very clean bevel and a sharp edge with a very tiny burr. I remove this burr by placing the top of the tool flat against the side of the Tormek wheel for a couple seconds to remove the tiny burr. Note that you can also do this with a diamond hone. Make sure that the hone is flat so that the edge doesn't get rounded over.

Next I use the steel on the top of the tool angled slightly towards the edge to make a very small forward facing burr. This step may be skipped.

Next, I put the steel against the bevel and roll the burr upwards.

Then, I angle the steel about ten degrees or so towards the edge and with slightly more pressure I pull a heavier burr. You should very easily be able to feel it with your fingernail running on the back side of the burr. Just don't slide a fingertip along the burr.

Try it out on a piece of wood. If the burr is rolled over too far then the results will be like scraping with a dull tool. If the burr is too small then the results will be mostly dust and a few small shavings ... not very exciting. A perfect bur will enable you to literally turn a entire bowl out of green wood and get beautiful shavings. It took me a lot of tries before I finally got it right. I think that Alan Lacer helped me the most because of the one-on-one situation.

Here is an article in Popular Woodworking.

Here is another good description of how to put a burr on a cabinet scraper.

Here is an article on sharpening scrapers by Alan Lacer that appeared in American Woodturner.

And, one more.

I have learned a lot from the links provided. thanks. Now I can follow the post and have a better understanding about the discussions.

What is most interesting to be is the fact that I am quite sure I read the 2008 article back in 2008. But at that point in time I was using a whole lot of 80 grit sandpaper. So it didn't really sink in. Now I am much more receptive to the information.
Thanks again.

 

[hockenbery]

I have learned a lot from the links provided. thanks. Now I can follow the post and have a better understanding about the discussions. What is most interesting to be is the fact that I am quite sure I read the 2008 article back in 2008. But at that point in time I was using a whole lot of 80 grit sandpaper. So it didn't really sink in. Now I am much more receptive to the information. Thanks again.

Tom,
We all have had similar experiences with not being ready to learn something.
We all need context and reference points to be able to assimilate new ideas in a meaningful way.

I have seen certain demonstrations a half dozen times and yet something new will click in a different way.
It isn't usually because the demonstrator left that part out the previous 5 times....

Al

 

[odie]

OK, the experiment is done.....took a couple hours, and the results did surprise me!

I thought I'd see no improvement of the raised burr over the ground burr, but there is a slight but noticeable improvement to the overall quality of the cut while using a shear scrape for the finest of cuts possible before sanding. I am going to incorporate the Veritas into my turning regimen for a limited, but important use.

I used three scrapers for the test, and did a final finish cut on about a 1" section of the exterior bottom of a bowl. I chose a hard maple roughed bowl with a section of burl for the test. The ground burr did a very acceptable finish cut, and then I cut that surface away with a gouge and started over with the raised burr. The difference is very small, but it is noticeable, both in the surface itself, and how the tool handled with a very light grasp in the hands......the feel of it was just a little bit smoother, in my opinion.

A Norton hard Arkansas stone was used for removing the burr left by the SG Norton 80g grind wheel....took it off cleanly with a couple of quick swipes. I have quite a few Sorby scrapers that are 1/2" thick.....these I can't use on the Veritas, because the carbide isn't tall enough. This, I don't see as a problem because I can switch to 3/8", or 1/4" thick scrapers when I want to use a raised burr.

It doesn't look like the raised burr is going to replace the ground burr for most of the general shear scraping, but will be in addition to it. Funny, how all these years, I had been thinking the ground burr was raised by the carbide, instead of removing it, and raising an all new burr.....I guess my mind was locked in on that, but this thread, and a little hands-on experimenting has opened my eyes to something I see as a valuable revelation!

I thought I'd get to this experiment hours ago, but after church, I took off for a short bicycle ride to check on the mail...ended up going right on past the post office and putting in about 30 miles, took about 3 hours of riding at my slow pace! I still need to package up the three bowls I sold this week-end.....and, pay some bills! Guess I'll do all that in the morning.....I'm tired out, and will crash in a few minutes.

ko

 

[Bill Boehme]

The burnisher was designed for use with high-speed steel scrapers. It is possible to roll a hook on carbon steel scrapers with a hand burnisher, but with high-speed steel you need a great deal of force and I have found that the fulcrum pin gives me the stability I need to really lean into my work.

If this came from the Lee Valley website, all that I can say is that the person who wrote that has a great misconception about the difference between carbon steel and high speed steel. Both fall into the category of tool steel and the difference in hardness is not very great. There are many other factors such as toughness and wear resistance that determine an alloys suitability for a particular purpose. Furthermore, when we talk about pressure (force per unit area) to deform metal we need to keep in mind that the actual contact area on the cutting edge by the burnishing tool is infinitesimally small, so it only takes a few ounces of force to create a tremendous pressure that is able to deform the metal enough to create the burr.

if he is "leaning" into the fulcrum pin to create the burr, he has undoubtedly ruined the burr. I like the analogy that one of my references used: "buttering a slice of bread" to give the reader an idea of the amount of force needed. There's no need to lean into the butter knife.

 

[john lucas]

Odie Glad to find out your a fellow bicyclist. I just moved and when I ride the 10 miles to town there is a 5 mile hill I have to come up to get back home. I'm not saying I'm all that slow but buzzards circle around me while I'm heading back up. I guess they figure I'm gonna die any minute.
I have looked at the Veritis burr raising tool and keep thinking I'll build one one of these days. Should be easy to turn and harden a piece. However now that I've used John Jordan's ceramic burr raising tool I may or may not ever make one. I thought it required a lot of pressure to raise a burr so the Veritis made a lot of sense with the leverage pin. However with John's ceramic cutter you just polish off the old burr and then use the same tool to pull across the tip to raise the burr. One or two strokes with moderate pressure is all it takes. With his tool I"m more satisfied with the burr than when I use the grinder.
I do have a home made scraper that I built years ago and using the grinder raises a better burr on it. I'm still experimenting with the burr on my older HSS round scraper that I reground into a negative rake. It seems to raise a nice burr of the stone but I haven't really played with raising it by hand. Of course my shop is still packed away so unfortunately I can't just run out to the shop and try it like I usually do.

 

[Gerald Lawrence]

Odie Glad to find out your a fellow bicyclist. I just moved and when I ride the 10 miles to town there is a 5 mile hill I have to come up to get back home. I'm not saying I'm all that slow but buzzards circle around me while I'm heading back up. I guess they figure I'm gonna die any minute.
I have looked at the Veritis burr raising tool and keep thinking I'll build one one of these days. Should be easy to turn and harden a piece. However now that I've used John Jordan's ceramic burr raising tool I may or may not ever make one. I thought it required a lot of pressure to raise a burr so the Veritis made a lot of sense with the leverage pin. However with John's ceramic cutter you just polish off the old burr and then use the same tool to pull across the tip to raise the burr. One or two strokes with moderate pressure is all it takes. With his tool I"m more satisfied with the burr than when I use the grinder.
I do have a home made scraper that I built years ago and using the grinder raises a better burr on it. I'm still experimenting with the burr on my older HSS round scraper that I reground into a negative rake. It seems to raise a nice burr of the stone but I haven't really played with raising it by hand. Of course my shop is still packed away so unfortunately I can't just run out to the shop and try it like I usually do.

All this talk about the Veritis tool and there are other options. I think the idea of the veritis tool is convenience and speed so that is can be mounted handy. You can make your own burnishing rod from a screwdriver with a polished shaft or a valve stem (which is polished as I understand). So fancy tool is not needed , just must be hard and polished to work best. Some of the answers about the advantages of grinding a burr or raising one are very enlightening.

 

[Bill Boehme]

It looks like I have a rare tool, a Hirsch Werkzeuge eiförmigen burnisherr (oval burnisher). It is as hard as a file and very smooth surface. I could not find it anywhere on the Internet ... not even on flea bay.

 

[john lucas]

Bill I have an Oval Burnisher. don't remember when or where I bought it but I've had it for more than 20 years. Mine almost looks Chrome.

 

[stu senator]

Burnisher

I made a burnisher from a hardened steel pin .250" dia by 2" long in a handle. It has a few marks on the polished surface but using the fingernail edge test it is mostly still smooth with a small bit of pitting. Still very useful and cheaply replaced.

 

[John Torchick]

Interesting thread here. May be a bit off topic but my grandfather said a knife wasn't sharp unless you could shave the hair off the back of your hand. Don't some refer to turning tools as "scary sharp?"

 

[Gerald Lawrence]

I got my oval burnisher at Lee Valley. They call it a Tri-Burnisher.

 

[odie]

I made a burnisher from a hardened steel pin .250" dia by 2" long in a handle. It has a few marks on the polished surface but using the fingernail edge test it is mostly still smooth with a small bit of pitting. Still very useful and cheaply replaced.

View attachment 8532

I was thinking about making one like that, but from the shank of an old dulled drill. I know they are hardened, but I'm wondering......? In order for it to work, it must be harder than the M2 steel in my scrapers......so, is it harder? That is the question......!

I was also thinking that the oval shape would probably work better than the round shank of a drill bit. If I did it right by grinding and dipping in water frequently, I could create a flat spot on the drill bit shank without changing the hardness of the hardened shank. That might be a lot easier to raise a burr on my 1/2" thick scrapers....you think?

For 1/4" and 3/8" scrapers, the Veritas seems to be doing a great job of it.....it would be hard to improve on that!

I also have a small piece of flat carbide used for metal lathe cutting. I may be able to adapt this piece to use for raising burrs on my 1/2" scrapers.......that is, if the drill bit idea doesn't work out for me........

ko

 

[stu senator]

Steel Pin

A dowel pin is case hardened to 60Rockweel C per spec.

Applicable Standard: ASME B18.8.2
Alloy Steel; Core Hardness Rc 47-58
Case Hardness Rc 60 min.

A stainless pin is much softer so do not use.416 Stainless is hardened to 36-42 Rc. 303 Stainless is not hardenable by heat treatment.

What is the tool hardness? It is often tempered to increase toughness (less brittle) or strength.

As an oval and a round will both have a point contact there should be no difference in the use except as a presumption to sell the oval shape.

A point contact will require less force then a line contact to raise a similar burr. A point to consider as you get older and have to work smarter rather then harder.

Stu

 

[john lucas]

You need to use a file to find out if one metal is harder than another. We call it a skate test. just lightly go across the metal. a hardened tool it will skate across. With experience you can sort of tell which piece is harder. Won't tell you how hard but will give you some idea if it's been hardened and which steel is harder. turning tools tend to be 58 to about 62 rockwell. Drill shanks should actually be kind of soft so they will bend instead of break but I sure can't speak for how they are all done. Screw driver shanks are also somewhat soft. Some of the steel used in copiers and printer rollers are really hard as well as engine valves.

 

[robo hippy]

Well, I was off in the woods camping at my booth at the Oregon Country Fair, aka Hippy Fair. Most fun event, and best sales event ever. Anyway, scraper burrs, my most favorite tool for heavy roughing and shear scraping....

The Alan Lacer article was done in 2008, and I think I was the only one using CBN wheels at the time, and they are the composite type with a 3/16 inch layer of matrix bonded to an aluminum hub. Later came the electroplated type. So, the burr.... I prefer the burr straight from the grinder and a CBN wheel which on a broken in wheel are more like a burnished burr. They are far superior to the burr straight from the aluminum oxide wheels, which raise a wire type edge which has no or little strength, and will break off or bend over easily. I prefer the burr from the 180 grit CBN wheel for fine finish shear scrapes, and the 80 grit burr for heavy roughing. There is little difference between them though. I have honed a burr on the scrapers with a 400 grit CBN and diamond cards. There is little difference between them and I can tell no difference in durability, though if I want the heavy roughing edge, the 80 grit CBN wheel is superior. I can remember being at the AAW Symposium in Portland in 2006 I think, and I watched one demonstrator who said, flat out, that it was impossible to turn a burr with a hand burnisher on HSS. He then proceeded to really crank on his scrapers with one of the Veritas burnishing set ups. Of course, I had to try out hand burnishing. He is flat out wrong with his statement that it is impossible, and I found out that it takes very little pressure to turn that burr, and only one or two light passes will make a fine burr. I do prefer the triangle burnishing tool to the round one. If my bevel is at 70 degrees, I have the burnishing tool at 80 to 90 degrees. I haven't been able to detect that the burnished burr is in any superior to the ones from straight from the CBN wheels. I think both are superior to the ones from the standard grinding wheels. Yes, you can crank way too hard with the Veritas tool, and if you take too many passes with the hand burnisher, and at too high of an angle, you can get a burr that rolls too far over like a breaking wave, and it does not cut well.

The only other debate I have heard on scraper burrs is upside down or right side up when sharpening. Jimmy Clewes is a fan of the upside down version. He feels that because the wheel drags the burr off the top side, you get a sharper burr. I tried it, and think that it is possible that that type of burr MAY be a tiny bit sharper, but isn't nearly as durable as the right side up burr. My current theory is that with the scraper right side up (same orientation that you use when cutting with it), because the abrasive is moving into the steel rather than dragging it off, you are doing some thing similar to honing the edge. For sure it is more durable.

Honed edges on gouges??? Well, especially since I started using the CBN wheels, I can see no advantage. With a well broken in CBN wheel, the edge is very polished. I have honed with the cards, and can see the polished edge on the heel and edge of the bevel, and can't tell any difference on my bowl tools, I do hone my skews, and will state clearly that I am not good with it, but there is a noticeable difference in how they cut when honed. For bowls, the critical point that I can determine is as much how high of a shear angle can I get, rather than how fine of an edge can I put on the tool. On the inside of a bowl, you can't drop the handle very much, so you need a tool that you can roll way over on the side. With Doug's fluteless gouge, I can easily go to 70 or higher, which compares to the dropped handle swept back grind on the outside of a bowl. Of course, I do all my shear scrapes with my scrapers.

robo hippy

 

[Fred Belknap]

I have quite a few Sorby scrapers that are 1/2" thick.....these I can't use on the Veritas, because the carbide isn't tall enough.

Odie I have the Veritas burnisher and the pins on mine are tall enough to do my 1/2" Sorby scraper. I have had it for around three years so yours may be an older model. They might supply you with taller pins. The pins on mine are at least 1/8" taller than my Sorby scraper. I use it a lot on final finish on my bowls.

 

[odie]

Odie I have the Veritas burnisher and the pins on mine are tall enough to do my 1/2" Sorby scraper. I have had it for around three years so yours may be an older model. They might supply you with taller pins. The pins on mine are at least 1/8" taller than my Sorby scraper. I use it a lot on final finish on my bowls.

Thanks, Fred.....good to know.

I've had that Veritas for close to 25 years, and most of that time, it's been neglected and unused. If you have been following this thread, you know why! It's definitely not tall enough to service my 1/2" Sorby scrapers, so the ones they sell currently may indeed have a taller carbide post. From my inexperienced point of view (even though I've had it for a loooong time), the old Veritas appears to be doing a very good job of easily raising a virgin burr (after the ground burr is removed).

I'm now doing further experimenting and gaining some "stick time" with the raised burr, and I like what I see! I'm thinking I may just have to scrap the old Veritas, and purchase the new and improved model! We'll see. Regardless, the old model will be useful for all my scrapers, with the exception of the 1/2" Sorbys. I use the shorter scrapers regularly, so I've got what it takes to do my own lab work for awhile!

Thanks again, ko

 

[odie]

If you compare the height of these two Veritas burnishers by eye......the new one on the right definitely looks taller to me.......

 

[odie]

Note to Bill Boehme........

If you make the angle of the grind closer to 75° to 80°, measured from the top surface, it makes it much more difficult to "curl" the raised burr.

ko

 

[Bill Boehme]

A dowel pin is case hardened to 60Rockweel C per spec.

Applicable Standard: ASME B18.8.2
Alloy Steel; Core Hardness Rc 47-58
Case Hardness Rc 60 min.

A stainless pin is much softer so do not use.416 Stainless is hardened to 36-42 Rc. 303 Stainless is not hardenable by heat treatment.

What is the tool hardness? It is often tempered to increase toughness (less brittle) or strength.

As an oval and a round will both have a point contact there should be no difference in the use except as a presumption to sell the oval shape.

A point contact will require less force then a line contact to raise a similar burr. A point to consider as you get older and have to work smarter rather then harder.

Stu

The dowel pin is too soft. HSS used in turning tools typically ranges between HRC 61 -63. A high speed steel drill has about the same hardness as turning tools so they would not be suitable either.

 

[stu senator]

Two things

Drill shanks typically get burrs from drill chucks and they can be removed with a file.

Too use the short pin veritus tool with a thick tool flip the tool over and use a shim to keep the burr off the base.

Stu

 

[odie]

Too use the short pin veritus tool with a thick tool flip the tool over and use a shim to keep the burr off the base.

Stu

Thanks, Stu......I'll give that a shot.

ko

 

[odie]

In a weak moment, I broke down and purchased the new Veritas last night. I had an order with Packard, and added it to the list........

Now, I have two Veritas burnishers........

ko