Bowl Scraper Recommendations

Hello everyone,

I have been doing a lot of looking at bowl scrapers, specifically Inboard scraper (as Robert Sorby calls it). I have actually purchased the Robert Sorby Inboard Scraper (8008LH) from Klingspor for $89 which I thought was a good deal but turns out, it is on backorder until NEXT YEAR. Me being impatient, I was looking for an alternative. I found the Glenn Lucas French Curve Negative Rake Scraper at Craft Supplies.

My question is two, maybe three fold. Should I be patient and wait for the Sorby to come in?? (most of my other tool are Sorby's). Should I cancel the Sorby order and go for the Glenn Lucas?? The Sorby is not a Negative rake (can you make it negative rake). The Glen Lucas is. Do I need a negative rake?

Any and all discussion will be helpful. Thank you in advance.

Sorby Scraper
Glenn Lucas Scraper

 

You can make anything negative rake, or reshape anything to something else, with some time on the grinder. You don't want to do this too often, though, as you'll waste a lot of steel. I've got both the heavy and light Sorby scrapers, and quite like them, but I'm learning that I blow up fewer bowls using a negative rake scraper on bowl interiors.

 

Karl, do you have the Sorby scraper you have reshaped into negative rake?

 

No, I've kept my Sorbys flat; I've ground other scrapers to be negative rake.

 

It might be worth looking up my video 'Scary Scrapers'. I use scrapers more than most, and it is my go to tool for heavy bowl roughing. I prefer the 1 by 5/16 inch scraper from Doug Thompson. For some reason, the M42 HSS stock goes from 1/4 inch to 5/32, and then up to 3/8, and that is too thick for my taste. Other than that, I use the Big Ugly tool for my main scraper because that edge lasts longer than any other tool I have.

As for which scraper do you need, I do like the 'inside' bowl type scrapers, though I don't use a long swept back profile. I do keep both regular and NRSs of several shapes and profiles. I really need to get my NRS video done... I prefer the standard scrapers for shear scraping, and the NRS for clean up work. The NRS works better on harder woods when used for bowls. They are wonderful for sweeping across the bottom of a bowl to flatten it out. When you start going through the transition and up the side, they don't cut as cleanly, and I prefer a shear scrape (I have a video on that too) for that cut, most of the time. The NRS excels for end grain turning like boxes. It is fairly easy to get finish cuts that require little to no sanding.

robo hippy

 

A scraper can be ground to any profile you will use - you have to be able to sharpen it or its of no use. You can also grind your own negative rake scrapers. You dont want to constantly change the profile of a scraper. You may change a tool a few times as you figure out what works. Have multiple tools with different profiles and std vs neg rake.

I use std and nr scrapers but as clean up/finishing tools, hence M2 steel is good enough for me. I probably have 8-10 scrapers of various width,thickness, and profile, plus a shop made 45 deg tool using M2 tips of various styles, and some shop made carbide hollowers which scrape and can be used on bowls. For bowl ID’s I use a slight curved nr for the bottom, and a std with a rounded point on the right and curving / sweeping to the left edge, probably similar to what you have been looking at. I like 1/4-5/16 thick material for mass.

 

Cancel the Sorby order and get a Thompson Lathe Tools scraper. No idea what his inventory is like.

 

OK, but with Thompson tools, do I have to buy a handle as well? I can understand his website.

 

You get what shows in the picture. It will need a handle, but it's very easy to make one. Won't take an hour if the price bothers you

 

The Thompson tools are great, but I'm not sure I'd get one until I had CBN to sharpen on. Maybe you do, Mark. Also, exploring scraper shapes and angles would be easier and less expensive to do with M2 steel.

 

If you're in the mood to experiment, you could get one or more cheap scrapers (such as at https://www.pennstateind.com/store/LX189.html) and have fun playing with the grinder. Once you find a shape you like then buy a nice Thompson or D-Way or etc.

 

I've sharpened my Thompson bowl gouges for probably 15 years on aluminum oxide wheels. There is not a steel tool made that can't be sharpened on aluminum oxide.

I sure wouldn't throw away money on a couple of cheap scrapers so you can play with a grinder. With that kind of money, you can buy a high quality tool for wonderful results. Start with a partial curve, then you don't waste any steel if you want a full radius latter. Personally a partial curve is just perfect for the bowls I turn.

 

There was no CBN available that I know of when Doug Thompson started making his tools. The Aluminum Oxide wheels work just fine for 10V or 15V steel. The main fact for me is that with CBN you take off less steel when sharpening. One of my grinders has an Aluminum Oxide stone on it for reshaping. It is a sight to behold to see Doug sharpen gouges a hundred at a sitting or to watch him reshape a scraper into a negative raked scraper at a symposium. What would take me an hour he does in minutes.

 

In the sharpening video on Doug Thompson's website, he does not use CBN wheels!

 

I'm with Bill. I sharpened Thompson tools for many many years on white and blue AOX wheels. When ingo the CBNs it did seem to sharpen quicker but not any better. The other benefits of CBN wheels such as always running true and never changing size or need turning are what make them great.
Now back to original question. Just find a good buy on a flat tool and grind it to your need. I replace the burr on my scrapers so.often I'm not sure if one tool holds that burr longer than another. I like the way a freshly rolled burr cuts so I make a few passes and renew the burr. What does seem to make a difference is tool mass. I have an old Henry Taylor about an inch and a half wide and 3/8" thick. That thing is so controllable when you make a cut. I do like my Thompson scraper that is 1" x 5/16" but if you have to hang the tool.over the tool.rest more than an inch there's no comparison. However a negative.rake.scraper is supposed.to be used to take light delicate cuts to.produce a better finish. I have a homemade carbon steel.scraper that I sometimes use. It is 1"x 1/8" and does a fine job as long as you keep.the overhang to an absolute minimum.

 

I have and use a CBN now, but just saying it's not an absolute necessity. Were you able to get CBN wheels 15 years ago? I wasn't. You should have seen the wheels I started with 35 years ago. Somehow right? Like I'm not very often? LOL
Edit; Huh, no response so I guess it wasn't a mistake or joke. Good to know.

 

Just one of the differences between CBN and standard grinding wheels, the CBN wheels are available in grits up to 1000. The standard matrix type wheels are most common in 120 grit and lower. You remove less metal each time you sharpen.

robo hippy

 

Richard, my point was not that you couldn't or shouldn't use an AlOx wheel to sharpen Doug's tools, but, as others have pointed out, that CBN is an appropriate match to the harder steel and helpful to bring out its best features. Also, I presumed, perhaps falsely, from the OP's post that he was a novice at scrapers and would end up boogering up grinds and using up a lot of steel while he gained skill. I couldn't afford to do that with a $100 tool.

Bill mentioned watching Doug take 100 of his tools and putting an inital grind on them with a stone wheel, as he does in his shop. I wonder how many tools he can do before he has to replace his wheel. Just curious. I never came anywhere near wearing out an AlOx wheel, but I only went through a couple of Doug's gouges before switching to CBN.

 

I did not think it was common knowledge that you need a cbn wheel to sharpen Doug Thompson steel. I don’t think he even uses one in his sharpening videos.

It’s funny how people hear things then assume it’s the only way, or best way to do something. I sharpened dougs steel fine on white wheels, and yes I do use cbn now, but all I find is I can sharpen without taking off as much steel.

 

The gray wheel.doug uses to shape the tools may be similar.to.the one on my 35 year old craftsman that I have use to grind everything including my early lathe tools and I have probably only used up 3/4" in 35years.

 

Pleased to see all of the input concerning sharpening with cbn vs alox. I have read cbn sharpens the carbides better, whereas alox can pull them out of the edge. Perhaps, but a lot of testaments here that the actual edge in use is no different. I use a Grizzly Tormek knockoff with Tormek jigs, which may remove less steel than cbn when resharpening.

 

i would think that to get an edge sharp you have to remove a certain amount of steel to flatten the rounded over edge. A slower speed grinder may make it easier to not remove anymore metal beyond what it takes to get the edge back but it's really a judgement call. that's partly why people have gone to 350grit or higher wheels, they remove metal much slower so it's easier to stop when it's just enough.

 

agree - usually 2-3 passes raises a burr on the inside of a gouge, sometimes it takes 5-6 passes to get one.

Im not trying to sell anyone on a wet grinder being a panacea. I use it because I already had it before I started turning. If the benefit of cbn is longer tool life due to less steel removed, and longer wheel life, there probably is no benefit to me changing to cbn either on the wet grinder or the bench grinder I use for shaping. My last wet wheel lasted ~ 7 years, with a lot of abuse learning how to sharpen flatwork blades and then turning tools.

 

Correct me if I'm wrong, and my thinking may be, but the quality of an edge is in proportion to the size of the grinding abrasive cutting that edge, be it sandpaper on wood or grinding wheel on tool steel. 25 years of 60, 100, and 120 grit aluminum oxide wheels has demonstrated this to me. If one is claiming a finer-than-120 grit CBN wheel is providing a better quality cutting edge than a 120-or-courser aluminum oxide, it is most likely due to the finer grinding abrasive. That is to be expected.

The knock against 120 or finer aluminum oxide wheels was how quickly the surface voids between the abrasive particles would load with grinding waste from the tool, requiring re-dressing of the wheel surface.

I've used aluminum oxide 7" wheels on my Baldor for nearly 20 years. A few quick swipes of a t-handle diamond dresser when the wheel builds waste, and a periodic dressing with the Oneway diamond jig keeps them in good shape. When I bring a tool to the 100 grit fine wheel I'm currently using, in 3 to 5 light passes of the jig held tool over the wheel I am back to cutting wood. I don't say this to discount CBN wheels, which I have no experience with, but to say that all this talk does not really compare the wheel cutting grit apples to apples. Yes, the CBN may provide a superior edge to the aluminum oxide, but different griding grits are being compared. If the CBN is the state of the art for the exotic steels that have become more common, then use them for those tools.

Oh, the days of decades past when turners poo-pooed using anything finer than a 60 grit aluminum oxide wheel on M2 or early particle metal turning tools.

Steve.

 

I've discussed this before but Jimmy Clewes has some out-of-the-box thoughts on sharpening that certainly need to be rolled into this discussion. It is his belief that we turners do not need a finely sharpened edge on our tools (with the exception of the skew). He says that a tool sharpened on an oxide wheel (rather than a CBN) leaves a microscopic ragged edge that aids us in cutting wood at the speeds and frequency that we turn. He can layout an entire discussion on the reasoning that makes absolute sense...that ends with the logic that it is not that critical to buy an expensive CBN. He applies the same logic to sharpening a scraper...and he advocates (and demonstrates it) that scrapers should be sharpened upside down on an oxide wheel for the very best burr. Now there is no doubt that there are some notable advantages to a CBN (minimum wear, loading, etc.) that have been outlined in the above discussions. However, I consider Jimmy Clewes one of the masters in our community and he sure does make us think about some common practices that I certainly have had for years and years. I always hoped that Robo and Clewes would have a discussion on the scraper sharpening topic...and I'd pay admission to hear their discussion.

 

There does still seem to be some debate about which type of edge works best and lasts longest. Some, like Mike Mahoney, say that a coarser edge cuts better and lasts longer. Some say that a finer edge cuts better and lasts longer. I don't think I have ever sharpened on a wheel coarser than 80 grit. I seldom use it any more, other than for minimal shaping. I did find that the 180 CBN wheel edge and burr for my scrapers work excellently. For the 600 grit edge, it seems to me that it works fine for finish cuts, especially in very difficult or soft woods, but for heavy roughing it doesn't hold up very well.

I do remember being across from Doug's booth at one of the Symposiums and watching him shape tools. I am certain that he has a high speed grinder. I have no clue as to what grit wheel he has on, but it was pretty coarse. Dave Schweitzer, former owner of D Way, used to use a 10 inch 60 grit wheel on a high speed Jet grinder. Both seem to get the job done. If I have to shape a tool, that is what the 40 grit belt on my big belt sander is for.

Using the diamond hand held hones just never seemed to work for me, other than using a coarse card on my McNaughton tips to raise a burr.

robo hippy

 

Doug not only uses a coarse wheel but he uses one of those hooded dressers to dress the wheel, but he uses it by banging it into the wheel to get it a little out of round so it cuts faster. Now my favorite tool is a 5/8V Thompson and the first 7 years I sharpened it with Aluminum Oxide. In those 7 years I used roughly 2 1/2" of flute (I know how to sharpen). After getting CBNs the next 7 years I only used a hair over 3/4". Now my personal grinder is only used by me, the Pros teaching and those doing the hands on get to use one of the other 2 grinders mixed with CBN and oxide wheels. I use the Vector Fixture which gives the hat turners grind and it is only three light touches (left right center) and its back in action. I think either CBN or oxide gave me the same sharpness but CBN sure saves a lot of steel.

 

To add a thought since we do not know what Doug is thinking for sure but we can hypothesize . He is not turning and not concerned with how much steel he removes . He is manufacturing and speed of steel removal means more money in the til in less time. So my theory for the gray wheels is that they remove more steel faster, which I think has basically been stated several times in this discussion just not related to manufacturing process.

 

Sorry that this runs long, and apologies to Rex for hijacking his thread, but we need to think this through.

I do not buy into the notion that a microscopic ragged-edge-off-the-wheel provides a superior cutting experience on a scraper. (Or any tool for that matter.) It simply does not. The "burr" left behind from the grinding process is not usable cutting steel, it is waste metal, the deformed and unsupported damaged material (as seen under magnification) that sits on top the actual tool edge. Think of it as... sparks that didn't become sparks... (Think the edge of torn paper vs. the edge of sheared paper.) That waste metal burr is so fragile and unsupported that one can break away the most fragile parts of it with a fingertip, and the rest will disappear in a fraction of a second once the wood finds it. It serves us no productive purpose. Someone name one other woodworking cutting tool that cuts in that matter. None. Drill bits, saw blades, carving knives, router bits, jointer/planer knives... none. What's the difference between our woodworking process and all the others? For us, the wood moves and we hold the tool more or less stationary, the others it is just the opposite, but a cutter is a cutter is a cutter... It cuts.

Think of an edge as a line where two plains come together. Ideally that line has no saw tooth pattern to it when viewed under magnification, it is a smooth, essentially 1-dimensional line. An edge has no thickness. The edge on a gouge is the 1-dimensional line where the bevel below the edge and the tool flute above the edge meet, and nothing more. Working through successively finer grinding grits results in a smoother and smoother transition line between those two plains. The grinding burr... is the sawdust on the surface waiting to be swept away, so to say.

(I'd argue that the best quality edges, regardless of the grinding angle, will be found at that line where two ultra-smooth, highly polished surfaces meet each other, creating an even smoother intersection of the two plains. But I've never heard of anyone polishing the bevels and flutes of their turning tools. Someone must. The closest we get is turners who hand-hone their skews with 600 grit or finer diamond plates. Knife makers live and die by finely polished bevels on each side of an edge, grits to 8000 and higher, and edges that make our best sharpened tools look like butter knives. Imagine today's exotic steel turning tools, how much better- sharper- their edges could be if the flutes were finely polished like drill bits, then grind the bevels on the fine CBN wheels.)

What makes one edge tough and long-lasting and another edge fragile and short-lived is the angle at which the two plains come together, how much mass is supporting that edge. A scalpel is incredibly sharp, has no discernible waste metal burr, and is ground in the single-digit degree angle range. But that edge is not strong due to the thinness of the metal behind the edge. We use turning tools with bevel angles between about 30-60 degrees- lots of beef supporting the edge, with scrapers having bevel angles up to about 80 degrees. The wider the angle in degrees, the "less sharp" an edge can be. That 80 degree scraper edge isn't going to cut, it is going to tear.

But, a scraper, when properly prepared, does not scrape, it cuts. It cuts not with a waste metal grinding burr (that we turners over time have adopted as an acceptable cutter), it cuts after we hone off that waste metal and then use a material that is just as hard, or harder, than the scraper to burnish, or roll the edge upward to create a microbevel hook edge. The exact same way a cabinet scraper or card scraper is prepared and presented to a flat board. (This does not happen from a grinding wheel.) The "relocated edge" atop that microbevel, which rubs on the surface of the wood and supports the cutting edge just like the bevel on any other turning tool, is what cuts the wood. Bludgeoning the wood off with a non-microbeveled edge that has a grinding waste burr on it is not cutting. It is tearing fibers through friction, not shearing fibers by cutting them. Not to advertise, but the Veritas "Scraper Burnisher for Woodturners" does a wonderful job of proper final tool preparation before cutting with a scraper. https://www.leevalley.com/en-us/sho...as-scraper-burnisher-for-turners?item=05K3501 See the instructions for details on the process.

In the end, just like sanding abrasives for wood, it's up to the user to decide how fine of a grinding grit to progress through in an effort to create an "acceptable edge" for the purpose. We don't need woodturning tools to be scalpel sharp, we need them to be acceptably sharp and durable for cutting wood effectively. That includes scrapers. Maybe we need to rename scrapers, and quit thinking of them and using them as that name would imply. Poor scrapers, all they hope to do is cut, we need to help them get to that goal.

Thank you for your time,
Steve.

 

It's refreshing to know that turners can be just as bad as hand tool flat woodworkers when sharpening discussions (angles, steels jigs, etc.) get going. Everyone seems to have an opinion, and that's all most have.

When I first started hand tool work years ago, I'd read every sharpening thread thinking there must be a magic bullet that would transform my work to the next level of greatness if I could only get things a little sharper.

What I discovered was, the only thing missing was my experience and technique. I didn't need to get my tools any sharper, I just needed to learn how to properly use them.

I've found the same with turning.

The collective "we" can spend every last cent on the newest tools, the best steel, grinding wheel, grinder, jig, gadget and magic foo foo dust, and argue that each of us knows the best way, but nothing will compensate for lack of technique.

There are those who will continue to argue over methods, tool steel and every other aspect of sharpening, and that is fine. Some enjoy the discussion and collecting of toys more than turning.

For those that are starting out, get tools you can afford, decide on a sharpening method (singular), start turning and learn how to use your tools. Don't worry about all the different types of grind, angles, tool steels and whose name is on a tool.

 

Well said, Tim.

Steve.

 

Steve,
Well, my experience with using scrapers as my primary roughing tool when turning bowls does not agree with your statement on burrs. I have been using the burr, straight from the grinder, for years, and my scrapers cut better with the burr than they do if I don't have it on. The burr on the Big Ugly tool lasts through multiple bowls. Yes, this is a roughing cut, and the surface of the wood is left rather rough. This can vary a lot, depending on the wood species. The burr can vary a lot, depending on how you sharpen. If I really push the scraper into the grinding wheel, the burr is not as good as one where I just brush the grinding wheel. Also, the CBN wheels leave a better burr than the old standard grinding wheels. Using a 180 grit CBN wheel, I get a burr on the V10 tools from Doug Thompson, and the M42 HSS tools from D Way, that will last through one big bowl easily. I seldom use them for that purpose any more as the Big Ugly tool outperforms them both by a huge margin. I have a couple of videos on the Big Ugly tool, and one called Scary Scrapers, and another on shear scraping. With shear scraping, I do prefer a burnished burr. I have not used the Veritas burnishing tool as it is rather limited and designed for scrapers pretty much exclusively. I use a small carbide rod in a handle so I can vary my angles to what ever the tool bevels need.

I did see a turner who did finish cuts on some sugar maple, which is very hard. He did use a scraper that was honed both on the bevel, and on the top. It left a very nice surface. That cut would not work on soft maple. This is due to the nature of the wood.

The negative rake scraper, NRS, is another scraper that cuts with a burr. Not sure exactly why, but the grinder burrs on them are very fragile, and are gone in seconds. A burnished burr lasts and cuts a lot longer. There are those who say that if you sharpen it upside down, that gives you a sharper burr, but again, that one is very fragile. With the NRS, I prefer 60/25 grind, and again a burnished burr.

All bowl coring tools are scrapers. They all cut better with a burr than they do with a honed edge. A honed edge will work in softer woods, but not well. Put a burr on it, straight from the grinder, and it works a lot better.

robo hippy

 

I was going to start a new thread but found this so I’ll add to it.
I have a question about using a burnisher on a NRS. I have had Glen Lucas’ NRS for a couple of months, and love it. Never have a catch, and usually get a pretty good finish, but I find I’m often pushing pretty hard with it, even fresh off the grinder. I made a burnisher with a carbide steel rod I got from EBay and mounted in a handle. I’m not sure I’m being very successful with it, as it seems to take LOTS of pressure to raise anything that feels like a micro-curl on the edge. Is the Veritas burnisher the best way to go with this? Is my carbide the wrong solution? Or is the burnished edge really unnecessary?
In reviewing this thread, I only see one or two mention of a burnished edge. Do most folks just work with the edge off the grinder? Thanks!

 

In another post John lucas recommended these!
https://www.stewmac.com/luthier-too...-tools/scrapers/stewmac-ultimate-scraper.html

I was trying to do a wing on a bowl with lathe shut off. They look awesome, and they are on my need this list!

 

What are the top and bottom bevel angles? Should be 90 deg or less. You are using it with the grinder burr up, correct? Can you see ANY reflected light from the edge? Grind the bottom bevel after the top bevel. What type and grit of grinding wheel? Depending on the grinder burr you may not notice much from the burnisher.

Grinder burrs dont last long at all. I hone my nrs’s with a diamond hone, 600 and usually 1200. Then burnish. Doesnt take much pressure. Top of Rod tilted 5-10 deg away from the edge. I use an LV burnisher which I really like but it is not necessary. It does allow a lot of pressure to raise a good sized burr if desired. Honed and burnished burrs last a lot longer.

 

Doug, thanks for your reply. Just went to measure. The included angle is about 84°, symmetrical between top and bottom. 180 grit CBN wheel. Yes, burr is up. I just finished with a thin walled maple bowl, and was a bit more satisfied with the shavings I got, but I feel like the burnisher is sort of skating off the edge of the scraper. Should i feel any resistance (not sure that’s the best word, but I don’t know how else to phrase what I feel like I’m looking for) when I’m burnishing?

 

My favorite NRSs have a 60 degree bevel on the bottom, and about a 25 or 30 on top. This set up, for me, works best for a burnished burr. With the skew chisel type NRS, say a 30/30 or 40/40, there is not enough metal to sustain a burr, though some do otherwise. The burnished burr does outlast the grinder burr by a huge margin. Now, when using the NRS, if you have to push at all, then your tool is dull. It is not a tool for any type of roughing, though a burnished burr can be used on boxes, I find that way too slow.

Burnishing, and I do briefly mention this on my sharpening video, a honed bevel will produce the best burr, though most of the time, I don't bother. I can take a quick pass or two on the top bevel, which pretty much breaks off the grinder burr, and then burnish the bottom bevel. To burnish, if your bottom bevel is 60 degrees, then you hold your burnishing tool at about 65 to 70 degrees, and all it takes to raise a good burr is 2 or 3 very light passes. You don't have to armstrong it. If you are burnishing a 60 degree bevel at 120 degrees, you can turn a burr, but it comes off at too much of an angle, and you have to really raise the handle to get it to cut. If you make a bunch of very heavy passes, you can get a burr that looks like a breaking wave for surfing. Again, you have to raise the handle high to get it to cut. Feel with your thumb. You only need a tiny burr to cut and if you can feel the burr, then it will cut. You do need a hardened rod for burnishing. With the M42 and V10 tools, a standard burnishing tool for the shop card scrapers does not work well. Carbide works best since it is harder than the fancy steels.

robo hippy

 

No you wont feel much resistance at all passing the burnisher over the edge, and at the “edge of the edge” it will skate off. Just for the heck of it try honing the bevels, finish with a pass or 2 on bottom, then burnish, see if you turn an edge. You can always put the tool in a vise so you can apply more force but its not really needed. You do need a keen edge. Ive made the mistake of sharpening and burnishing an nrs and there was no burr, because I didnt get to a fine edge to begin with. Robo makes a good point about rolling the burr too far and needing to raise the handle to engage it.