NRS vs scraper

[Emiliano Achaval]

A friend was telling me that I probably went about the wrong way on my last post about gouges vs scrapers. Scrapers have their place, in an arsenal of gouges, lol. What I dont like is someone starting only with scrapers and or scraping techniques. Just had a little run in with a beginner down south. I gently tried to tell him that if he cut the wood his piece would look much better. He used some kind of pine, and you know what happens when you scrape soft pine...
A few months ago I turned my mini scraper, yes, you heard right, I do have scrapers, and lots of them, lol, I turned it into a mini NRS, the one that I use to finish my hollow forms. If you ever turned Koa, you know how finicky she is... The mini NRS left a beautiful surface. The scraper used to do a decent job, but the mini NRS in my humble opinion is an improvement. One last thing, not every wood likes the NRS, some, like Milo, leaves a glassy surface, a 10. There are different grades of Koa, some Koa cuts like Kou, super nice, some Koa no matter what you try you won't get a nice surface on the end grain. Aloha

 

[john lucas]

One thing I've found us that small round cutters cut cleaner than straight edges on difficult surfaces. For example my 3/8" detail gouge will leave a cleaner cut than my skew even though they both have the same included angle. I don't really understand it since I am taking what appears to be the same width shaving with each tool. I've done this experiment many times when I have difficult woods turning mirror handles and each time it works. I have also done this experiment using a larger Hunter cutter vs the small Hunter cutter. The smaller cutter will cut cleaner. The smaller cutter is more aggressive so it takes care get a smooth line on the surface but the cut will be cleaner. I'm guessing that's the same with NRS.
I don't mind starting vessels with a scraper. Your just wasting away wood so what ever is quicker and easier. One day I was roughing out a really out of round piece. I swapped back and forth between my 5/8" bowl gouge and my Hunter Hercules. The Hunter was less stressful and easier to use. Once I got it round the bowl gouge was easier and more fun. As you approach the final shape of course I much prefer cutting. Scraping damages the surface far below the surface so it you get too close to the final shape you have to cut away a lot of wood with your cutting tools to get the final surface clean. If the tearout from scraping goes too deep then you have to alter the surface shape to get past it. sometimes that can be a bad thing. That's why excessive sanding of torn grain areas produces a divot that may look OK but feels terrible when you run your hands across the surface.

 

[robo hippy]

Well, I probably use scrapers more than just about any one out there..... For heavy roughing, they can't be beat, but they do leave a rough surface. If I want a finished surface, then I use them for shear scraping or bevel rubbing cuts, and yes, you can do a bevel rubbing cut with a scraper. I am still trying to figure out the NRS. As some one who absolutely has to experiment, I have them from 25/25 to 80/30, and every where in between, and I use grinder burrs and burnished burrs on all of them. I seem to get a lot better results with the NRS on harder woods than on softer woods. Also, I get better results on end grain than on flat grain. With shear scraping, grain orientation doesn't seem to make as much difference compared to the NRS. I have only had one piece of Koa to play with, and it had sat in a dry shop for many hears. The only way I could get clean cuts was to wet it down and then take very light cuts, taking 3 or 4 wettings to get rid of the tear out. I did use a scraper once with a honed edge to turn a lamp base in some figured sugar maple because I had seen Nick Stagg do that in a similar hard wood. I was able to get a 220 grit sanding surface. As a scraper psycho, "totally and in all ways inconceivable!" I don't care for big heavy burrs on my scrapers, but burrs from the 180 CBN wheel seem to work for most cutting, and a lightly burnished burr for shear scraping. I recently watched Dale Larson demo, and his shear scrapers had really heavy burrs that he burnished. Hmmm, may have to experiment some more...The amount of tear out seems to be related in part to the wood (don't do it on punky wood), and how heavy your cut is. When approaching final shape, I am much more gentle, which leaves a better surface. But, every piece of wood is different...

robo hippy

 

[George Guadiane]

This is a bead raising tool from Veritas. When a freshly sharpened and honed scraper has a raised bead on it, it can make shavings virtually identical to finished cuts of a well presented perfectly sharpened gouge. AND it can rough aggressively when desired.
I had been told about the advantages of this system for YEARS and I resisted. A friend did one of my scrapers with it and asked me to try it out... I went out and got one right away. I now have two.
I'm another one who doesn't get negative rake scrapers. The people that use and love them get great results. It seems to me that changing the presentation angle of a regular scraper to match the same angle of an NRS "should" (NOT scientific) produce the same results.

 

[Emiliano Achaval]

This is a bead raising tool from Veritas. When a freshly sharpened and honed scraper has a raised bead on it, it can make shavings virtually identical to finished cuts of a well presented perfectly sharpened gouge. AND it can rough aggressively when desired.
I had been told about the advantages of this system for YEARS and I resisted. A friend did one of my scrapers with it and asked me to try it out... I went out and got one right away. I now have two.
I'm another one who doesn't get negative rake scrapers. The people that use and love them get great results. It seems to me that changing the presentation angle of a regular scraper to match the same angle of an NRS "should" (NOT scientific) produce the same results.

George, I have had this burnisher for many years. When I moved my shop it went in a drawer. I should give it a second try. I just remember not been able to "feel" a burr when using it, like one off the grinder. Do you feel it or is it so tiny that you don't? Thanks.

 

[Emiliano Achaval]

One thing I've found us that small round cutters cut cleaner than straight edges on difficult surfaces. For example my 3/8" detail gouge will leave a cleaner cut than my skew even though they both have the same included angle. I don't really understand it since I am taking what appears to be the same width shaving with each tool. I've done this experiment many times when I have difficult woods turning mirror handles and each time it works. I have also done this experiment using a larger Hunter cutter vs the small Hunter cutter. The smaller cutter will cut cleaner. The smaller cutter is more aggressive so it takes care get a smooth line on the surface but the cut will be cleaner. I'm guessing that's the same with NRS.
I don't mind starting vessels with a scraper. Your just wasting away wood so what ever is quicker and easier. One day I was roughing out a really out of round piece. I swapped back and forth between my 5/8" bowl gouge and my Hunter Hercules. The Hunter was less stressful and easier to use. Once I got it round the bowl gouge was easier and more fun. As you approach the final shape of course I much prefer cutting. Scraping damages the surface far below the surface so it you get too close to the final shape you have to cut away a lot of wood with your cutting tools to get the final surface clean. If the tearout from scraping goes too deep then you have to alter the surface shape to get past it. sometimes that can be a bad thing. That's why excessive sanding of torn grain areas produces a divot that may look OK but feels terrible when you run your hands across the surface.

My 1/4 Thompson gouge leaves the best finish of all my gouges. Maybe because we go instinctively slower with smaller tools we leave a better surface? Hmmm

 

[hockenbery]

My 1/4 Thompson gouge leaves the best finish of all my gouges. Maybe because we go instinctively slower with smaller tools we leave a better surface? Hmmm

I think the small tools get sharper. They certainly have less bevel drag.
And certainly I take light cuts with it.

I have a 1/4” Thompson with Michelson grind.
I use it for details and when I return a dried bowl I use it to finish the first inch inside a bowl.
Also use for hollowing balls for the ball in ball.
Great little tool - seldom leave home without it.

 

[George Guadiane]

George, I have had this burnisher for many years. When I moved my shop it went in a drawer. I should give it a second try. I just remember not been able to "feel" a burr when using it, like one off the grinder. Do you feel it or is it so tiny that you don't? Thanks.

With an adequate grind angle and an adequate amount of pressure you can feel the burr. More importantly, if you can see the burr coming off when you hone it to regrind, that shows that it's there.
The burr doesn't have to be significant to cut nicely. Only the actual sharp edge does the cutting, so how high it stands isn't that important.

I should note that in my experience you should only raise the burr with one single pass. More than that and you might actually roll the burr over past the point where it will cut.

 

[robo hippy]

Well, first, NRS vs scrapers, one would think that by raising the handle on a standard scraper you could get the same effect that you get with the NRS, but not so. One turner described it as a 'trailing' cut. Think of it this way, If you use the card scrapers from the flat work world, you rub the bevel, and angle the card into the cut till it starts to cut. You can tip it a bit more forward and it cuts fine. If you tip it really far into the cut, then instead of getting a nice slicing cut it is more like dragging a rake through the wood fibers.

As for the Veritas burnishing tool, I have never used one. I just hand burnish a burr on my scrapers with a small carbide rod in a wood handle. The first time I ever saw the Veritas used, the turner really cranked down hard on the scraper because 'you can not hand burnish a burr on M2 steel because it is too hard.' I didn't tell him that I had been doing it for a while. Dale Larson uses it, and when checking out his burrs on his scrapers, they were really big, and he commented that he didn't shear scrape on the inside because it was too aggressive. My guess is that is the burr and not the cut, or tool. I have been playing around a lot with taking the burr from the grinder, burnishing it down, which may break it off, and then burnishing it back up. This seems to do a good job, but not sure if it is as good as the one where it is honed and then burnished. I do take a dull burr and turn it down, then back up again a couple of times before going back to the grinder. This is also common on card scrapers. Most of the time, the grinder burr is fine for both heavy roughing and shear scraping. For difficult woods, then I go with the burnished burr. Nice thing about the burnished burr on a NRS is that they are a lot more durable than the grinder burr. I can burnish a burr on a 30/30 NRS (Eric Lofstrom does this and he will demo in Portland, well worth watching because he is 'different'). Bevel is at 30 degrees, and burnisher is at 35 or so, and I can hear the edge breaking, kind of like krinkling the celophane cover from the old cigarette packages. Still puts up a nice burr that lasts longer than the grinder burr... I don't see any end to this experimentation.... Engineers: "If it ain't broke, take it apart and fix it anyway."

robo hippy

 

[Breck Whitworth]

I'll throw my 2 cents into this discussion or forum topic. Since I turn bowls almost everyday I have had the pleasure and frustration of learning about and using scrapers and negative rake scrapers. I love a 70 degree scrapers for serious cutting or making a tenon or recess. I use my 70 degree scrapers all the time to finalize or smooth and area when rough turning on green wood. I never could get the negative rake scraper to be very effective for me until I tried a 33 degree neg. rake scraper on both sides like Glen lucas's. Now it is one of the most important tools I have for finishing a dried bowl. It is a delicate scraping cut that is perfect for that small area that just won't cooperate. The burr is tiny but cuts wonderfully and is like I said a great finishing tool.

 

[john lucas]

Breck Is that 33 degrees on both sides (66 total) or is it 33 degree included angle My negative rake scraper has an included angle that is probably around 70 degrees but i haven't measure it. It seems to work fine but I'm always looking for better.

 

[Don C Davis]

OK folks, help a rookie out--how in the heck do you get such precise angles determined and done on your tools--I am a knife maker so I know how to do it on a knife blade, is that the same approach you use on a NRS--also if you are using a replaceable blade tool, like the Stuart Batty tools do you remove the blade from the tool to get the edges you are after?? Also, is there a particular NRS you all would recommend??? And what size would you go with??

 

[john lucas]

I don't worry about exact angles. I like to know so I measure them with a cheap measuring gauge just so I can answer questions for other people. I purchased a scraper blank from Doug Thompson and ground mine to a radiused negative rake scraper. I would love to have one like Stewart Batty's but it's out of my price range. I have an older 3/4" flat scraper that I ground as a flat negative rake. It's nothing like 33 degrees. It is less than 90 but not much. Seems to work well for what I use it for but I don't use scrapers very much.

 

[robo hippy]

Don, easiest way to get consistent and repeatable angles is to have the same angle on each side, and then set your platform, sharpen one side, then the other. Burr up side is the one you use. If you have a removable type set up for your scrapers, then generally it is a bit easier to sharpen with them out of the handles, especially if you have a big heavy handle. Most of the time when I use a NRS, I don't have it in the handle because only the lightest touch is necessary and I keep the tool rest close. The burr is gone in seconds, so many trips back to the grinder. I have no idea why Glenn chose 33/33 for his NRS. I wouldn't think that a few degrees either way would make a significant difference, but haven't tried to be that precise.

robo hippy

 

[john lucas]

I have my Robo Rest set at 45 for my negative rake scrapers but it really gives me a slightly more acute edge. I'm sure it's the way I set it up and my grinder not the Robo Rest. I do as Reed says. I flip the tool over so both sides have the same angle

 

[Breck Whitworth]

Breck Is that 33 degrees on both sides (66 total) or is it 33 degree included angle My negative rake scraper has an included angle that is probably around 70 degrees but i haven't measure it. It seems to work fine but I'm always looking for better.

John it is 33 degrees on both sides, but when you grind, you grind lightly on only one side. this leaves a fine burr. almost impossible to get a catch or a dig in but cuts beautifully. I just bought Glens scrapers because I wanted to keep my regular ones with the 70 degree angle for serious scraping. Oh and you can do a wonderfully delicate shear scrape with these also. I was amazed at how easy and effective his double 33 degree neg. rake scrapers are to use.

 

[john lucas]

I"m still confused. Are you saying it's 33 degrees measured from bevel to bevel or the grinder is set to 33 degrees which would give you a 66 degree bevel to bevel. I know I sometimes use my skew laying on it's side with no burr. It is ground to 35 degrees or close to that.

 

[robo hippy]

It is supposed to be 33/33, so included angle at 66. I would consider a 45/45 to be good for a burnished burr. I like using the / instead of calling it 'included angles'....

robo hippy

 

[Don C Davis]

OK, what in the world are you guys talking about 'burnishing a burr' in knife making burnishing is for eliminating a burr--the truly sharp things in life--say a razor blade or a scalpel or even a knife in general that are truly sharp, have been honed to ELIMINATE any burr. Those who say when turning with a burr you have to go back to the grinder frequently--I should imagine--a burr raised on a tool that is then applied to woodturning would surely go away very quickly if you are cutting against it. I think I will continue to hone my edges--several of which are on tools that are hair shaving sharp, and just continue in that manner.

 

[john lucas]

Don What we do in turning is to actually raise a burr. When you lay a sharp skew on it's side for example it will scrapes. If it's really sharp it will scrape off ribbons but on the outside of the bowl it doesn't work quite as well. On the inside, no way because it's shaped wrong. So we grind a tool kind of similar but then after it's ground to a point we actually raise a burr using a technique we call burnishing. Basically you take a hardened piece of steel and rub it across the edge raising the burr. Quite often when you run a tool across the grinder it raises a burr on the top side. This works really well on some steels and other require raising the burr with a tool we call a Steel. We often grind a piece of steel to a rounded nose to use inside a bowl as a scraper. If we grind off the top so the tool appears to have a bevel like a skew we call it a negative rake scraper.

 

[Don C Davis]

John, thanks for that information, it is beneficial to know the difference in application of terminology from one industry to another--I often see a burr after sharpening certain tools-like my round nose scraper-a Crown Powder Metal one, and it cuts superbly right after I grind it on my CBN wheels. So I can see what some folks are after with what woodworkers term 'burnishing' certainly a different meaning of that term in this world--Thank a lot for sharing your knowledge sir!

 

[Bill Boehme]

OK, what in the world are you guys talking about 'burnishing a burr' in knife making burnishing is for eliminating a burr--the truly sharp things in life--say a razor blade or a scalpel or even a knife in general that are truly sharp, have been honed to ELIMINATE any burr. Those who say when turning with a burr you have to go back to the grinder frequently--I should imagine--a burr raised on a tool that is then applied to woodturning would surely go away very quickly if you are cutting against it. I think I will continue to hone my edges--several of which are on tools that are hair shaving sharp, and just continue in that manner.

Don, if you are familiar with the burr on cabinet scrapers used in flat woodworking, it is essentially the same thing. When you raise as burr on a woodturnings scraper (using the same type of tool that you use to remove the burr on a knife edge) you are replacing the weak ragged burr that is the result of sharpening on a grinding wheel with a much smoother and stronger and very sharp burr that is actually a cutting edge.

 

[robo hippy]

Burr from standard aluminum oxide wheels is more of a wire burr that breaks off quickly and is very weak. Burr from CBN wheels is pretty rugged and great for heavy roughing and some finish shear scraping cuts. Raised burr is done by rubbing a piece of metal or ceramic against the bevel of the tool, and usually the tool is the softer of the two metals so this turns up a very sharp and very strong edge. I don't use them as much for heavy roughing, but more for shear scraping. For a cutting knife, you do not want the burr, like on a skew chisel, which is honed. There are degrees of honing as well. The honed edge on a carving blade or hand plane blade is usually a lot finer than the edge on a skew chisel because a skew will be pulling off a lot more wood. Burnished burrs are usually used on more blunt angles like scrapers, in the 70 degree range, but not on more acute/pointed angles like skew chisels, but some negative rake scrapers are pretty much skew chisels. The burnished burr is probably the toughest and sharpest, but some times it isn't worth the effort. Are you confused yet???

robo hippy

 

[Don C Davis]

All good intel folks--Robo that post actually clarifies a bit for me--appreciate it!!

 

[john lucas]

One more thing. When you need a really really fine edge on a tool (not necessarily a turning tool). Sharpen and strop in the normal fashion. Then gently drag the edge against a piece of wood. This breaks off the burr however small it may be. The strop it again. Now you have a really good edge.

 

[Bill Boehme]

Burr from standard aluminum oxide wheels is more of a wire burr that breaks off quickly and is very weak. Burr from CBN wheels is pretty rugged and great for heavy roughing and some finish shear scraping cuts.....

I've noticed what you say about the burr on CBN wheels since putting one on my Tormek. This is a big (and not what I was hoping for) change from what I have been getting with the standard Tormek gray stone which leaves a much smoother edge. I think that CBN wheels are much better suited for bench grinders where they leave a more polished bevel. I believe that the very slow 90 RPM's of the Tormek and higher pressure needed while grinding are the reasons for the poorer results.

 

[robo hippy]

Bill, do you know that there are diamond wheels for the Tormek now? Glen Lucas said that after a year, there was no degrading of the wheel at all, but with CBN, he finds them 'new homes' after a year. Can't remember if this has come up here or not...

robo hippy

 

[Bill Boehme]

I suppose that Glen Lucas has been testing pre-production diamond wheels. The latest word from Tormek is that the diamond wheels will be available sometime in June. Knowing Tormek, they won't be cheap. I'll wait too see what others think about them.

 

[john lucas]

Won't be as expensive as my wife's diamond ring. That one keeps costing me.

 

[Breck Whitworth]

I"m still confused. Are you saying it's 33 degrees measured from bevel to bevel or the grinder is set to 33 degrees which would give you a 66 degree bevel to bevel. I know I sometimes use my skew laying on it's side with no burr. It is ground to 35 degrees or close to that.

John the bevel on the scraper is ground at 33 degrees exactly the same for both sides (here is a link to a video for how to sharpen his scrapers) to me a picture is worth a thousand words.

View: https://m.youtube.com/watch?v=g-b4IM4Jy0c&ebc=ANyPxKrhx6kFBRJD8kfhNKVdTtDbN4XSSajH79fdOHBOLCyXC-ydlHHQve8QC3dtEzS46YiSe58LfSjjAL5ZIQf-g0tg27euuA&time_continue=2

 

[Emiliano Achaval]

Why not just use a skew on its side? I do that with hardwoods... I saw Ashley's Harwood NRS, at first glance I thought she was going to use the skew... Guilio Marcolongo uses a skew just like a NRS, he uses it in all of his work, very successfully... I would like a comment by @robo hippy and @john lucas on this scientific question... lol

 

[john lucas]

Thanks Brek. So it's what I call 66 degree included angle. Of course there is a difference in grinding the same angle on each side (like Stewart Batty and Glen) although they use slightly different angles. Not sure there is much difference in actual use.


A skew on it's side works but you will find if you raise a burr it will work better. Of course if your going to use it on the inside of bowls you need a pretty good rounded edge on your skew. Many people think that using a skew as a scraper is the only good use for a skew.

 

[robo hippy]

Well, they are skews.... That is what the first ones were, and I have no idea how long they have been around, but they were here before Allen Batty started turning. I think the biggest difference is that now we have a lot of dedicated NRS's, and they tend to have more curved nose profiles, while the skew is usually more straight across. I have several that I some times use for skews, and for peeling cuts. The peeling cut ones have a bit of a straight across/90 degrees to the shaft, and then a sweeping 1/4 round profile.

robo hippy

 

[William Rogers]

Why not just use a skew on its side? I do that with hardwoods... I saw Ashley's Harwood NRS, at first glance I thought she was going to use the skew... Guilio Marcolongo uses a skew just like a NRS, he uses it in all of his work, very successfully... I would like a comment by @robo hippy and @john lucas on this scientific question... lol

Well when I first started turning pens years ago I just thought a skew was a scraper named skew. I never had any club or instruction I could go to and not much on the internet as there is now. I still use skews more as scrapers as I don't do much spindle work, but have now learned to use the skew properly.

 

[Bill Boehme]

Why not just use a skew on its side?

You can, but to function as a true NRS you would need to use a burnishing tool to put a small 90° hook on the edge. The skewed angle is sometimes inconvenient and as John mentioned, it would only work on outside curves.

 

[Emiliano Achaval]

Well, they are skews.... That is what the first ones were, and I have no idea how long they have been around, but they were here before Allen Batty started turning. I think the biggest difference is that now we have a lot of dedicated NRS's, and they tend to have more curved nose profiles, while the skew is usually more straight across. I have several that I some times use for skews, and for peeling cuts. The peeling cut ones have a bit of a straight across/90 degrees to the shaft, and then a sweeping 1/4 round profile.

robo hippy

Very interesting... I should mention that Guilio only uses the skew on the outside.

 

[robo hippy]

Bill, that is one of the debates about the NRS, grinder burr or burnished burr..... I was just out playing with some Oregon Myrtle, and using several different NRSs. 30/80, and 30/30 both with grinder and burnished burrs. Got about the same results. Too much of a hook and the tool doesn't cut as well.

robo hippy

 

[Bill Boehme]

Too much of a hook and the tool doesn't cut as well.

Too much force when burnishing will cause the burr to roll completely over. My very limited experience is that a grinder burr is good for about 15 seconds and a burnished bur is good for roughly one minute. Of course, this is very dependent upon the wood.