Do you burnish your scraper?

[Alan Heffernan]

I have seen this Lee Valley scraper burnisher as well as some homemade tools for this purpose.

I would like to know if any of you take the time to burnish your turning scrapers.

I suspect you need to hone the top of the scraper and then burnish a hook. Burnishing one fresh off the grinder without honing the top may produce a hook that is so rolled over it is less effective.

Interested in your experiences.

465467

[Reed Gray]

The main scraper I use for bowl roughing is the Big Ugly tool, which has tantung silver soldered onto the end of some bar stock. It gets a great burr from the grinder and doesn't need burnishing, though this material can be burnished. My more standard scrapers that I use for shear scraping, most of which are M42 HSS or V 10 (D Way and Thompson) I am still experimenting. Frequently the burr off of the grinder does a good job. I use wheels from 80 to 600 grit for my burrs. It can be turned down and burnished back up a couple of times, but presently, I am thinking that returned burr is not as sharp. I seldom go to the trouble of honing off the grinder burr. I have done that, and then burnished on a fresh burr, and it cuts very well, but not positive that it is a better edge. I have been turning some big leaf maple that has been problematic. For reasons unknown, I am getting tear out in one quadrant only, and nothing seems to take it out, including NRSs, 600 grit gouge grinds, and any type of burr for shear scraping. Standard tear out is in 2 quadrants, always... With the older M2 HSS scrapers, a burnished burr seems to work better for durability, but not sure if it provides a better cutting edge for shear scraping, haven't used them in years for that. I am currently experimenting with hand honing with a diamond card to raise the burr, going across the bevel rather than up or down. Mixed results, but most of it has been with this strange big leaf maple.

I do prefer to burnish NRSs (negative rake scrapers). I use a hand held tool with a 3/16 carbide rod in it. Hand pressure only. I also use it on my card scrapers. After much experimenting, I have settled on a 60/25 grind for my NRSs. The skew chisel types, in the 30/30 range have too acute of an angle to take a burnished edge, at least for me. I tried a 40/40, and a 45/45, and didn't care for them. I am thinking that you need a certain amount of metal under the burr to support it for longer cutting action and sharpness. The edge can be burnished down and back up again a couple of times.

As for the Lee Valley burnisher, it does have carbide rods. It is intended to be bolted down to your work bench. I never considered getting one. Main reason is that I have many different angles that I use, and it seems to be set for one specific angle. Another problem with it is that you can over burnish. By that I mean that it is easy to put too much pressure on the rod and scraper which yields a burr that is too heavy, and some times they can curl back too far which is not the best edge for cutting with. I prefer the hand held. My first one was a 1/8 inch carbide drill bit. You can burnish with the standard burnishing tools for card scrapers on M2 HSS. The triangle one works best. For the M42 and V 10, you pretty much need carbide.

robo hippy

[Alan Heffernan]

Thanks for the insightful reply Reed!

I have successfully avoided spending the money on the Veritas tool. It is too limited in application and therefore the 60+ bucks to get it in hand doesn't make sense to me. Guess I will make me a tool or use a Veritas handheld that I have already for some testing. I have some carbide milling bits that I have wrecked in the mill that could serve the purpose.

I have tried the skew chisels with a hook but the edge is just way too fragile for me and I decided not to repurpose a good tool (Dway) for that.

Your advice on the NRS of 60/25 is appreciated. I may buy some stock for that and grind my own. Do you have an opinion on the steel to use? M42 or PM10V? Thompson's blanks are attractive to me for grinding myself but I like the Dway stuff as well.

[tom lucas]

I burnish my scrapers sometimes. I bought a 5/16" dia carbide rod that is short and put a handle on it. I think it was about 3" long before I put the handle on it. Sticks out about 2" which is plenty for burnishing. Works good and didn't cost much. But you can only burnish a few times before the burr is too weak. Then you have to go back to the grinder for a second or two.

[John K Jordan]

I bought one of those burnishers years ago. I used it on a variety of scrapers including some that were very large.

That burnishing tool can be very aggressive because of the leverage the pin at the rear gives you. It can easily create a burr that is much too large to be useful. When used gently, it's fine.

I quit using the thing at least 10 years ago and instead use burnish with hand tools. I started with a fairly large diameter carbide rod then went to a smaller rod. I like the small one better.

465482

My favorite burnisher now is made by Arno, has a round rod on one side and a triangle on the other side. The triangle actually as a small radius on the working edge rather than a sharp edge so it really works like a small diameter rod. The triangle is more aggressive than the round rod. Sorry, I can't find a pic of the Arno.

I use the hand burnishers for scrapers, negative rake scrapers, and hand scrapers.

JKJ





I have seen this Lee Valley scraper burnisher as well as some homemade tools for this purpose.

I would like to know if any of you take the time to burnish your turning scrapers.

I suspect you need to hone the top of the scraper and then burnish a hook. Burnishing one fresh off the grinder without honing the top may produce a hook that is so rolled over it is less effective.

Interested in your experiences.

465467

[roger wiegand]

I burnish with a carbide rod-- Alan Lacer sells a nice kit with the rod and ferrule, you make your own handle to suit. You can also use the butt end of an old solid carbide router bit or other carbide tooling if you want to make one for near free. I had the Veritas jig years ago, it makes far too aggressive a hook for me. A light pass by hand is plenty to turn a burr for light duty scraping like cleaning up the inside of a bowl. I polish the top flat with a diamond teardrop card (also from Alan) then pull the burr. My scrapers go a very long time between trips to the grinder; the raised burr is smaller, more consistent and longer lasting than the burr off the grinder.

[Randy Heinemann]

I love the Veritas burnisher. For me it works well although I also have burnished my scrapers with a carbide pin mounted in a small handle. Both work well.

[Richard Coers]

I prefer the burr off the grinding wheel. Just a super light pass completely restores it.

[Reed Gray]

As for tool steel, I can't see any difference between the V10/Thompson and the M42 from D Way. I have a friend who is mostly retired now and he turned myrtle wood trays for the tourist shops for 30 or so years. He didn't notice any difference either. Funny thing about the M42, it comes in 1/4 inch, then 5/32, then jumps to 3/8. I use 1 inch wide ones. Just because I guess. You don't need a heavy tool for a NRS. The cuts you do are feather light, and if you have to push at all to get it to cut, then it is dull. I got a bunch of blanks from D Way so I could 'experiment'.... Smaller width ones are good for the insides of boxes.

robo hippy

[David M Peters]

Well this question feels like a poll, so I'll add in my answer that I don't burnish my scrapers. They get sharpened on the 80 grit wheel but normally are touched up with a hand hone.

[Alan Heffernan]

Well this question feels like a poll, so I'll add in my answer that I don't burnish my scrapers. They get sharpened on the 80 grit wheel but normally are touched up with a hand hone.

Thanks for participating in the poll David. Your response generated another question!

Have you compared the edge you get on the 80 grit vs. something finer? I have always wondered about that but have never taken the time to really investigate it deeply enough in the shop.

[Reed Gray]

I have sharpened and raised burrs with 80, 180, 320, 600, and 1000 grit CBN wheels. I settled on the 180 grit wheel. The burr I get from it seems to be every bit as durable as the 80 grit burr, and just as sharp. The finer wheels do leave a nice burr, but I don't think they are quite as durable. Part of the burr raising that can make a difference is how hard you push into the wheel. I have some times thought that if you grind hard, rather than just brushing the bevel against the wheel, you get a more aggressive burr, but not necessarily a better burr. For my McNaughton blades, Kel tole me to use a coarse/220 grit diamond hone to raise the burr. With those, I will hone across the bevel rather than up the bevel. This does seem to raise a better burr than the fine hone cards.

Side note, Jimmy Clewes is one who sharpens his scrapers up side down. He said this produces a finer/sharper burr. I tried it a few times, but didn't notice any real difference. I will say that I did not give this method a heavy duty work out, so maybe I need to play with it some more. I don't have a negative 70 degree setting on my grinder platform. I do have one that I can do at about 80 degrees.

robo hippy

[Edward Weber]

Keep in mind that the burr created by the grinder is weaker than the burr created by burnishing.
A burnished burr is considered to be work hardened and therefore much stronger.
A burr created by the grinder is much quicker to create/restore and is usually turners need.
YMMV

[Jeffrey J Smith]

I've gotten in the habit of hand burshing scrapers when needed - I sharpen scrapers on an older 80 grit cbn wheel (probably closer to the 180 when it was new. When going for a final sheer scrape, I grab a 3/4" D-Way skew and use the rounded edge to quickly burnish a nice burr. The M42 steel seems to turn a nicely hooked burr that lasts a little longer, and the skew was handy..
Got in the habit because I'm too lazy - and way too cheap - to go back to the grinder too often.

[David M Peters]

Have you compared the edge you get on the 80 grit vs. something finer? I have always wondered about that but have never taken the time to really investigate it deeply enough in the shop.

I have 80/350 CBN wheels. Scrapers off the 80 grit wheel just seem to cut better for me.

But then I'm contradicting myself by stating that I hand-hone them when they're dull, that's like a 600 grit finish. If scraper no longer feels sharp to my thumb (i.e. the burr is gone and the corner is a bit rounded off) then I'll hand hone it.

I'll also add that scrapers are not my primary tool, I'm trying to improve my gouge skills to get finish cuts from them. Listen to Reed if you want scraper expertise :-)

[John K Jordan]

Keep in mind that the burr created by the grinder is weaker than the burr created by burnishing.
A burnished burr is considered to be work hardened and therefore much stronger.
A burr created by the grinder is much quicker to create/restore and is usually turners need.
YMMV


Just compare the grinder burr to the burnished burr under a microscope. The grinder burr looks like a ragged and fragile edge while the burnished burr looks more like a smooth knife edge.

I've used both and almost always take the few extra seconds to hone off the grinder burr and add a burnished burr. The times I used the grinder burr I used CBN wheels from 80 to 600. 600 worked the best for me but none lasted as long as the burnished burr. The two do have a bit different "feel" in use.

Also, don't remember if I mentioned this earlier but when a burnished burr starts to get dull, I generally refresh it at least once with the diamond hone and burnisher before returning for a pass on the 600 grit CBN wheel.

JKJ

[Allen Mattsen]

I bought one of those burnishers years ago. I used it on a variety of scrapers including some that were very large.

That burnishing tool can be very aggressive because of the leverage the pin at the rear gives you. It can easily create a burr that is much too large to be useful. When used gently, it's fine.

I quit using the thing at least 10 years ago and instead use burnish with hand tools. I started with a fairly large diameter carbide rod then went to a smaller rod. I like the small one better.

465482

My favorite burnisher now is made by Arno, has a round rod on one side and a triangle on the other side. The triangle actually as a small radius on the working edge rather than a sharp edge so it really works like a small diameter rod. The triangle is more aggressive than the round rod. Sorry, I can't find a pic of the Arno.

I use the hand burnishers for scrapers, negative rake scrapers, and hand scrapers.

JKJ

You turned me on to that one and it works great!466328

[John K Jordan]

You turned me on to that one and it works great!466328

I'm glad you like it.
While searching for Arno recently I came across their knife sharpener which is made just like the burnisher except for different carbide inserts - one for removing metal from the knife edge and the other for smoothing the edge. I find it works great when I'm in a hurry and don't want to get out the sharpening machine!

https://www.amazon.com/Arno-Carbcut-Handheld-Carbide-Sharpener/dp/B07J17DMKS

JKJ

[Mel Fulks]

Agate burnishers were used by many old timers and considered the best. Dulled carbide laminate bits also work well.

[Allen Mattsen]

Just compare the grinder burr to the burnished burr under a microscope. The grinder burr looks like a ragged and fragile edge while the burnished burr looks more like a smooth knife edge.

I've used both and almost always take the few extra seconds to hone off the grinder burr and add a burnished burr. The times I used the grinder burr I used CBN wheels from 80 to 600. 600 worked the best for me but none lasted as long as the burnished burr. The two do have a bit different "feel" in use.

Also, don't remember if I mentioned this earlier but when a burnished burr starts to get dull, I generally refresh it at least once with the diamond hone and burnisher before returning for a pass on the 600 grit CBN wheel.

JKJ
You prefer the 600 grit wheel for your scrapers? I've mainly been using my 180 grit for flat style tools and the 600 for gouges, in part just to leave them set up for most common tasks...

[John K Jordan]

You prefer the 600 grit wheel for your scrapers? I've mainly been using my 180 grit for flat style tools and the 600 for gouges, in part just to leave them set up for most common tasks...

Yes, and I made some gages from plexiglas to very quickly set the wolverine platform for my most common angles for NRS, skew, hand scraper, etc.

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Since this picture, I started spray painting all of these on one side to make them easier to see and read. This one is for grinding a thin hand scraper at 90-deg. The 3rd pic is honing the edge flat before burnishing.

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This one is for my curved NRS ground at 60-deg, usable either left or right depending on which side I burnish the burr.

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I use a wolverine varigrind (not varigrind 2) for the bowl gouges, the tormek 1200grit CBN for the spindle gouges.

JKJ

[Allen Mattsen]

Yes, and I made some gages from plexiglas to very quickly set the wolverine platform for my most common angles for NRS, skew, hand scraper, etc.

466462

Since this picture, I started spray painting all of these on one side to make them easier to see and read. This one is for grinding a thin hand scraper at 90-deg. The 3rd pic is honing the edge flat before burnishing.

466463 466464 466465

This one is for my curved NRS ground at 60-deg, usable either left or right depending on which side I burnish the burr.

466466 466469 466472

I use a wolverine varigrind (not varigrind 2) for the bowl gouges, the tormek 1200grit CBN for the spindle gouges.

JKJ

Great idea w/ the plexiglass. I have some and so far been using a paper gauge that came w/ my NRS from D-Way tools. Do you just scribe a line or how do you form the gauge - surely not by grinding it down in the wheel, I imagine? I have plexi ready to use, this sounds like a good project.
A friend made me a 3-D printed setup gauge for 40° which is kinda cool. Maybe down the line...

[John K Jordan]

Thanks! I did shape the curve with the CBN wheel but only removed a TINY bit pf plastic!

- Set the tool rest platform on the grinder to the desired angle.
- Held a straight edge of a piece of plexiglas on the platform and tight against the flat side of the CBN wheel.
- Used a xfine sharpie to trace the curve of the wheel on the plastic.
- Carefully cut along the curved line with the bandsaw; cut a wide relief notch in the middle for a “two-point” contact (wide “points”!)
- With the flat held firmly and perpendicular against the platform, turned the grinder on then off and with wheel turning slowly gently
touched the gage to the wheel, refining and smoothing the two contact points. A fine grit CBN wheel may melt the plastic
a bit instead of cleanly grinding so I cleaned up the edges as needed with a sharp knife.
- Mark the angle and tool on the gage.

When I use one to set the angle of the platform I’m careful to hold the gage perpendicular to the platform AND the front of the wheel or the grind angle might be off a bit. These would be a bit easier to use if made from thicker material, say 1/4” or so but more effort to make. I might try making them from aluminum or steel and use two much narrower “points” to contact the wheel.

I do have a 3D printer so that might be a good option but would have to be careful to get the shape right for a specific tool angle since the tool thickness is much smaller than the two-point contact distance on the curve of the wheel. By making the gage to match a given tool grind that I like I don’t even have to know the angle! The important thing is the gage sets the platform so the grind is precisely repeatable so a clean grind on even a very thick tool only takes seconds and no extra tool steel has to be ground away.

I wouldn’t use these on conventional grinding wheels since the radius changes as they wear.

BTW, for most platform sharpening I prefer to use the mini platform instead of the larger one that comes with the Wolverine. I bought a couple of these through Amazon when they were $32.

JKJ


Great idea w/ the plexiglass. I have some and so far been using a paper gauge that came w/ my NRS from D-Way tools. Do you just scribe a line or how do you form the gauge - surely not by grinding it down in the wheel, I imagine? I have plexi ready to use, this sounds like a good project.
A friend made me a 3-D printed setup gauge for 40° which is kinda cool. Maybe down the line...

[Allen Mattsen]

Great info, working on gauges from plexi now :).

Question about your NRS's: I use one like those, straight on one side, and it makes me wonder why not just rounded all the way around? Is it just harder to raise a consistent burr if it was round nose in shape? There must be a reason for several with inside/outside or left/right orientation?

[John K Jordan]

Great info, working on gauges from plexi now :).

Question about your NRS's: I use one like those, straight on one side, and it makes me wonder why not just rounded all the way around? Is it just harder to raise a consistent burr if it was round nose in shape? There must be a reason for several with inside/outside or left/right orientation?

467174

Do you mean these?

I don't find it difficult to burnish a burr a scraper that is rounded all the way around.

I use a variety of negative rake scrapers and some are in face rounded around the top and part way down the other side, but not very far down the other side. In fact, I've seen pro turners at symposiums use such NRS and have seen some for sale. You can certainly grind it far down both sides but unless you use a very wide scraper it would tend to have a fairly sharp radius on the tip. This can be handy at times - I ground one with a narrow tip radius for a special purpose, to use on a small platter with a raised foot that had a smoothly curved and fairly deep cove "waist". I made the tool just to fit nicely into this tight area. (Sorry, I don't see that I took a picture of that NRS.)

However, if you look at the three above note they all have a short straight or almost straight tip. I've never seen anyone grind one that way (until after they saw some of mine) but I did it this way on purpose for a special reason. If I'm making a small squarish platter like this with square or almost square wings...

467177

... I can use the end to smooth flat areas and areas with very shallow curves. It even works very well on the wings themselves (used gently, of course). I've had people tell me you can't use scrapers on wings but perhaps they didn't thing of grinding one like this. If the NRS was curved on the end I don't think it would be as useful for general work.

I think the flat tip on the end makes it a little easier to control the tool, moving it back and forth gently (with the tool horizontal and held firmly flat against the tool rest, supported with the left hand close to and sliding against the back of the tool rest, thumb on top, left forefinger below).

I occasionally use the 90-deg corner at the end of the short flat has another purpose - smoothing right up to shoulder or bead, sometimes difficult to do another way.

I guess I could grind a very wide NRS with long curves down both sides and a flat tip but it might be massive and difficult to sharpen.

The first photo below shows using the flat tip to smooth the wings. I make the tops of most of these with shallow curves so on those I can use the flat end all the way from the edge to the center. Having a flat takes out more of the small variations typically left by the finish cut with a gouge.

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The bottom side of the piece, however, has tighter radii towards the foot so the long curve on the side is perfect for smoothing that. Also good for the insides of a bowl. The flat tip works well towards a flattened center of a bowl or a flat platter.

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Note that one huge goal (for me) for these scrapers is to eliminate power sanding with relatively coarse paper. Power sanding with coarse rotating disks has a number of serious problems. For years now I have not ONCE power sanded with a rotating disk such as on a drill. (My nice angle drill gets used for drilling holes in tight places!)

If I follow the finish gouge cut with the NRS and follow that with hand scrapers, I can almost always start sanding with 320 or sometimes finer paper. The hand scrapers can get the surface so smooth I often do all or most of the sanding by hand. If I use power sanding, it's always with VERY gentle random orbital action from a pneumatic ROS with 2" or 3" paper, usually 600 grit.

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If I made a lot of platters that were perfectly flat I'd probably grind one NRS, maybe a 3/4", that was straight (or almost straight) all the way across the end but with a slight radius on each corner to keep it from digging into the wood.

Using these tools for smoothing (after both initially shaping and making finish cuts with a Hunter Hercules tool), a relatively inexperienced student made this one as her first "real" project, a present for her sister. Previous to this she had a spindle lesson and few simple spindle practice projects, and completed very nice small bowl in her second lesson. Then she wanted something more challenging!

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You might not be able to tell by the photos but the surface was SO good, perfect, top and bottom. I finally found someone pickier than me! :)

BTW, I've done a number of turning club demos on all these techniques. When it's safe enough again I might be talked into doing some more.

There I go again, writing too much!

JKJ