Do Angles Count?

[Stuart Batty]

Angles are critical in woodturning. Both edge and wing angles determine how the gouge performs. The bevel angle directly contributes to how much pressure it takes to perform a cut. The wing angle and shape affects entry cuts and how the gouge removes the wood.

Knowing the angle of the cutting edge and being able to repeat the angle every time you sharpen will help in many ways. Firstly it will give you an understanding of how the edge will react when cutting. If you cut with the same angle on all your gouges you will develop muscle memory and therefore repeatability. A good example of this is when you grind your bowl and spindle gouges at the same edge angle, then both make entry cuts at the exact same position, in fact it will help with every cut. You will also start to notice when the edge is getting dull.

However, if you have your bowl gouge at 45° and your spindle gouge at 35° then they will cut very differently. The spindle gouge will be slightly more aggressive and want to almost self feed, your bowl gouge will require several times more pressure to cut than spindle gouge. This makes it difficult to know when the tool is starting to dull, the only way to know will be the end result; a dull edge will ALWAYS tear grain. It is worth noting that it is a physical impossibly to cut well with a dull toll, no matter how skillful you are.

The magic edge but not bevel angle for cutting wood on a lathe is 40°. There are some exceptions but we will get in to these another time. The reason I say edge angle and not the bevel angle is because these are different. A hollow bevel angle cannot be measured accurately, this is because the protractor is measuring across the edge and heal of the bevel. The actual cutting angle is the tangent where the wheel formed the edge.

Diagram 1 – 5/8” diameter bowl Gouge Cross Section with 40° Measured Angle

This image created in CAD shows the protractor-measured hollow bevel angle at 40°. However, the true edge angle is actually only 36.3°. A protractor measures from the flute and across the hollow bevel creating a false reading. The true edge angle is where the wheels tangent meets the very edge of the blade.

257839

Diagram 2 – 5/8” diameter bowl gouge Cross Section with 40 Degree Edge Angle

This shows a gouge that has a true edge angle of 40° but when measured with a protractor it would read 43.5°.
257840


The following Diagram is to show the bowl gouge in 3D with 40/40 grind I developed and now even used by my Dad, Allan Batty.

257838
This is one of the reasons I invented the Angle Gauge, which sets angles at the tangent of the wheel. I want accurate and repeatable angles. However, you can simply set you platform or jig to give you about 2-3° greater reading than the angle you want and you will be close enough.

Why 40°
40° is a neutral cutting angle; it is neither aggressive nor self-feeding. 35° or lower edge angle make the blade more aggressive and start to self-feed in certain cuts. At 45° and above the blade will start creating resistance to cutting. The highest usable angle for a gouge is 70° and this angle is only suitable for use at the vey bottom of a narrow tall side grain bowl. If you need a higher angle then this because of the shape then you need to change to a scraper.

Keep in mind that 40° is the same included angle used for Skews, Beading/Parting Tools, and Bedans. However, regular parting tools suit 50° better because they need to be used in at a scraping angle when first parting in to prevent the fibers being lifted to the sides or the blade being aggressive in certain applications.

Other professional turners who use 40° to push cut with: Cindy Drozda, Mike Mahoney, Allan Batty, Ashley Harwood, Keith Gotschall and David Nittmann.

More to follow over the next week or so. Stu

[Roger Chandler]

Very interesting information, Stuart.......thank you for sharing with us........good to have someone with your knowledge share and help us get a better technique on sharpening and learn how to help repeatability!

[charlie knighton]

thanks Sturart, we had a discussing a while back but true edge angle was not discussed

[Harry Robinette]

Thanks Stuart any of your knowledge is great to get. We only hope you'll keep popping in when you can and sharing with us.

[robert baccus]

Thanks much. Knowledge beats opinion every time.

[Thom Sturgill]

There was some discussion a while back about the Raptor set up tools and the angle they set. I believe you will find they are configured to set the tangent angle, but I could well be wrong as the documents don't say.

[Bernie Weishapl]

Thanks Stuart, that is some good info.

[Dan Forman]

Thanks for the explanation. I got a couple of your angle gauges, and wondered why there was a discrepancy between what the platform was set for and what I measured on the gouge. It was just as you said, and now I know why. :)

Dan

[John Keeton]

Great stuff, Stu!! I assume your diagram is based on an 8" wheel? You may have stated that and I missed it. I do understand the concept, and that is why I have used 42* in an attempt to arrive at something close to 40*. However, most of us have no real way to measure the actual tangent angle on a tool. Perhaps the only way is to do it on paper as you have done.

Thanks for the well stated concept. A pic is worth a thousand words, but a pic and an explanation is priceless!;)

[Reed Gray]

The thing that puzzles me, well, one of many thinsg anyway, is the relationship between the cutting angle, and the handle angles when you present the cutting edge to the wood. It kind of becomes a compound miter angle thing doesn't it? When you hold the tools level, the cutting angle/edge is different than if you drop the handle. I guess, do different angles work better or worse depending on tool handle angles?

robo hippy

[Wally Dickerman]

Thanks for all the info Stuart. I bought my first bowl gouge in about 1984 and am still learning all the various ways to sharpen and use it. In the early days the gouge came ground straight across much like a spindle roughing gouge. That was the most folks used it until the fingernail grind came into use.

That early bowl gouge was a Sorby and came with a 12 inch handle.

[James Combs]

The thing that puzzles me, well, one of many thinsg anyway, is the relationship between the cutting angle, and the handle angles when you present the cutting edge to the wood. It kind of becomes a compound miter angle thing doesn't it? When you hold the tools level, the cutting angle/edge is different than if you drop the handle. I guess, do different angles work better or worse depending on tool handle angles?
robo hippy
I could be all wrong here gut based on the technique of "riding the bevel" until the tool starts to cut, tool presentation angle should always be close to the same. The only difference for those folks that "drop the handle" versus those that hold it higher would most likely be the height of the tool rest. Those that drop the handle will probably start with a lower tool rest setting. Higher held tool handles will most likely have higher tool rests for the same cutting angle at the blank.

Someone step in here and explain to me why this would not be true if these assumptions are wrong.

[Mark Levitski]

Puzzling? Whew! I am puzzled by the inordinate weight placed on angles and the IMO indiscriminate use of the term for the basics for turning. Wanna get especially detailed and esoteric about this for the fine points and for entertainment (as in how many angels will fit on the head of a pin)? Fine, go ahead. But do you guys really think that 40 versus 42 degrees really makes a difference worth considering or talking about, especially for beginners? Not in my experience. And I've stated elsehwhere that I've noticed no difference worth talking about in the "sharpness" of a 40 degree bowl gouge nose edge versus a 60 degree one when they are off the grinder. Thinking that I might be a neanderthal turner who can't distinguish the difference? Or too much of a novice to know that? Go ahead, but I assert that it REALLY is not relevant enough to dwell on for all practical purposes.

First, let's make sure we're talking apples and apples.

1) Edge angles: Two opposing sharpened bevels intersecting, a sharened bevel and a machined flute intersecting, a bevel and a non-sharpened flat face intersecting.

2) Wing angles: As proposed, the angle from the mainline of the gouge to the edge of the sharpened wing. This is very different from the edge angle of the wing, which is the opposing angle of the wing bevel and interior face of the flute.

3) Handle angles: W/ reference to the bed ways.

4) Flute angles: W/ reference to the bed ways also. Most of the time described as on the face of the clock when facing the piece on the headstock.


Couple things to consider: The so-called 40/40 grind has a 40 degree wing angle. I find this irrelevant except for how one needs to hold the handle with relation to that edge. It is not sharper, it is not better or worse. Change the handle position and you can make a 40 degree angle any angle you wish. Any cutting edge knows not what is behind it as far as a handle or it's position to gravity and what "level" is. The way the turner presents the edge to the wood does, however, make a difference. But as far as the edge is concerned, it knows nothing about that part of it. Whether you have a short handle or long, or hold it high or low, the edge doesn't know. More clearly, I can hold the handle of a bowl gouge with a 15 degree wing angle (pretty close to level with the flute) a bit higher or less vertical in a pull cut that one with a 40 degree wing angle and the edge will have exactly the same orientation for shearing. No difference except for the way you need to hold the tool. No sharper, no more or less tearout, no worse or better surface. If you can present it by pushing the edge, this would not have any different result. It would surely make a difference for the turner if they somehow find it easier to control the cut or if they have an individual preference. IMO it is entirely misleading if one thinks that somehow one way is inherently better than the other, or that the surface is automatically going to be better.

I've seen far too many people try way too hard to find a secret technique that they can learn or copy that will make them instantly better turners. It is similar to the inclination to find a new and better tool for accomplishing the same thing. My recommendation is to keep it simple and to beware of one's urge to discover that one technique, sharpening angle, or new tool (or advice from those that are selling new tools) that will miraculously solve everything for you in your turning life. I don't care how long your mentors have been turning, what accolades they have received, or what their pedigree is. There is a lot of politics in art, and turning is a part of that world. You wanna win a dog show or win a dog race?

[Dick Mahany]

I, for one, genuinely appreciate the thoughtfullness and free sharing of the information presented here. I have become a more informed and better turner because of lessons learned here and am most greatful to those willing to share. Whether any of us agree or disagree with the information presented, it is certainly worthy of consideration and study. Considering the price I paid to recieve most of the great tips and info here, I can only say thank you for sharing and please keep the info coming !!

Stuart, I really appreciate the time you spent and the selfless sharing..............now I'm going to play with my 40 degree sharpening techniques ;).

[Lloyd Butler]

It is interesting and I have heard several turners talking about the grind and how they like it.

I am wondering if it makes a difference depending on the flute shape? The image #3 above looks more like a U or V where the wings would have more or less straight walls. If you have a gouge with a more C shaped flute, does the grind work as well? The wing cutting edge would be a different shape.

In teaching beginners, with roughing gouges, I like to have 2-3 different grind angles to show the difference in the work to make a cut with the various tools. Maybe that is why some people suggest 45 degrees as a good starting angle for the bowl gouge it really works out to just over the 40 Stuart was talking about.

Lloyd

[Fred Belknap]

This has been a great thread about a subject I don't know a lot about. I'm would class my self as an experienced turner although not in the league of many here. After reading Stuart's post I decided to give his idea a try. My bowl gouges were ground according to Doug Thompson's 60°, using his set up on the Wolverine jig. I have been mostly happy with how my gouges work. I have four bowl gouges so I decided to try two of them at 40°. I had a dry ash semi hollow form (semi means it has a hole big enough to use) on the lathe. Usually ash end grain on one side of an ash has a tendency to tear out. It is a turn/dry/return so it was out of round and about 7" diameter. Now after trying to get a perfect cut with the 40° grind, I came to the conclusion that for me I couldn't detect any great improvement. I tried the handle level and with it dropped. I could get a respectable cut with either grind. I started sanding with 100 grit. I'm not saying this means anything but is just my experience. One thing the 40° grind seemed to take a lot of metal off the wings of the tool. The tools I modified were a Sorby1/2" and a PN 1/2", both rather good tools.
Don't take my ramblings as anything other than ramblings.:D

[Dan Forman]

This has been a great thread about a subject I don't know a lot about. I'm would class my self as an experienced turner although not in the league of many here. After reading Stuart's post I decided to give his idea a try. My bowl gouges were ground according to Doug Thompson's 60°, using his set up on the Wolverine jig. I have been mostly happy with how my gouges work. I have four bowl gouges so I decided to try two of them at 40°. I had a dry ash semi hollow form (semi means it has a hole big enough to use) on the lathe. Usually ash end grain on one side of an ash has a tendency to tear out. It is a turn/dry/return so it was out of round and about 7" diameter. Now after trying to get a perfect cut with the 40° grind, I came to the conclusion that for me I couldn't detect any great improvement. I tried the handle level and with it dropped. I could get a respectable cut with either grind. I started sanding with 100 grit. I'm not saying this means anything but is just my experience. One thing the 40° grind seemed to take a lot of metal off the wings of the tool. The tools I modified were a Sorby1/2" and a PN 1/2", both rather good tools.
Don't take my ramblings as anything other than ramblings.:D

Fred --- Two questions here: Did you you do the 40/40 grind by hand, resulting in a 40 degree bevel all around the edge, or use the jig, but set to a 40 degree bevel nose, which will result in different angles for the nose and wings? Did you use a push cut while turning, or a pull cut? If either answer was the latter choice, especially for the second question (push or pull), you might not see the results Stuart is talking about. To see a push cut in action, take a look at this video, start at about 5:45 into it. Ashley Harwood - Wood Turner / Artist Charleston, SC on Vimeo (http://vimeo.com/26791233) .

Dan

[Reed Gray]

Stuart may have to step back in here and correct me as I don't really have the total grasp of this, or Nick Stagg (come on Nick, I know you are lurking out there). The 40/40 means a 40 degree bevel, and a 40 degree sweep (nose angle) to the wings. This grind can only be done by hand, and can't really be replicated by gouge jigs. A number who use this grind have a 40 degree sweep angle scratched into their platforms so they can be consistent with the grind. With the flutes rolled over to 90 degrees, on a platform set to 40 degrees to the wheel, you should have a 40 degree bevel on the nose and wings.

Another point on using this cut, and with any other cut actually, is what part of the gouge/flutes are you cutting with? I tend to roll my flutes over on the side a lot more than most, and am doing most of the cutting with the nose, and prefer a more open flute design. I think this push cut uses the flutes more vertical, and you cut some with the nose, and a bit up on the wing.

robo hippy

[Fred Belknap]

Fred --- Two questions here: Did you you do the 40/40 grind by hand, resulting in a 40 degree bevel all around the edge, or use the jig, but set to a 40 degree bevel nose, which will result in different angles for the nose and wings? Did you use a push cut while turning, or a pull cut? If either answer was the latter choice, especially for the second question (push or pull), you might not see the results Stuart is talking about. To see a push cut in action, take a look at this video, start at about 5:45 into it. Ashley Harwood - Wood Turner / Artist Charleston, SC on Vimeo (http://vimeo.com/26791233) .


Sorry guys I was using a Wolverine jig, probably why I got such an ugly grind. I don't do a very good grind free hand.

[Dan Forman]

Sorry guys I was using a Wolverine jig, probably why I got such an ugly grind. I don't do a very good grind free hand.

Fred --- You answered one question, how about the other one, push or pull cut? I think this is more important in terms of results than the grind. With a push cut, I bet you will get a cleaner surface, though if you aren't used to doing it, it will take a while to get down.

About this grind, check out this video by Mike Mahoney on grinding this profile. He uses 45/45, but it's the same technique to get 40/40, just adjust the tool rest to 40 instead of 45, and proceed the same way. To get your 40* wing angle, you can use a pencil or marker to draw a line that is 40* relative to the top of the grinder's tool rest for reference.

Stuart said he would post more information on the push cut in the next few days, so keep your eyes out.

Warning - this is not the same cut as Lyle Jamieson describes when he talks about push cut in his Youtube video.

There is a very good video by Stuart Batty and Mike Mahoney that compare and contrasts the two styles of turning that you can purchase online and download to your computer, assuming you have a broadband connection. Stuart Batty and Mike Mahoney - Two Ways to Make a Bowl (http://www.woodstore.net/pp-11-0033.html) It includes sharpening too. This is the only video that I know of that explains and demonstrates the push cut as taught by Stuart, though there may be others.

Dan

[Reed Gray]

Mike and Stuart do that demo at every Symposium. For sure, well worth watching.

robo hippy

[Fred Belknap]

Fred --- You answered one question, how about the other one, push or pull cut? I think this is more important in terms of results than the grind. With a push cut, I bet you will get a cleaner surface, though if you aren't used to doing it, it will take a while to get down.

Dan I tried both push and pull cut and I don't see a lot of difference. My method for getting a clean cut is to drop the handle and cut with the side of the gouge at about a 45° or less in reference to the toolrest. It does a pretty good cut. On the pictures you posted there was a remarkable difference in the cut. I am willing to give anything a try, if I mess up I have my other two gouges to go back to.

[Dan Forman]

Dan I tried both push and pull cut and I don't see a lot of difference. My method for getting a clean cut is to drop the handle and cut with the side of the gouge at about a 45° or less in reference to the toolrest. It does a pretty good cut. On the pictures you posted there was a remarkable difference in the cut. I am willing to give anything a try, if I mess up I have my other two gouges to go back to.


Fred --- I went down and took a couple of pics to show how I hold the gouge. I din't have anything in progress and on a faceplate, so I had to put a rough turned bowl on the vacuum chuck with the tail stock in place (no vacuum running) to demonstrate. I don't know why I didn't turn the vacuum on, which would have made it much easier, but it's late, and sometimes the mind is not the boss. :) These pics also illustrate the main difference between the two cuts. With the pull cut, usually done as you described, with the handle down at 45* and taking the shaving from the wing, the direction of the cut is going around the diameter of the bowl, as if the bowl were a coil spring, if that makes sense.

With the push cut, the direction of the cut is going from the base of the bowl to the rim rather than around the bowl, that's the way the gouge is being pushed, and the shaving is taken from the upper tip of the nose, not the wing. I think this is responsible for the smoother surface. The bowl in the picture is elm, which is notorious for tearout, there was none. Both pics are of the push cut, but taken from different angles.

http://i98.photobucket.com/albums/l279/T-Caster/DSC_1001_2.jpg

http://i98.photobucket.com/albums/l279/T-Caster/DSC_0999_2.jpg


This is all detailed very clearly in the video Batty/Mahoney video that I linked to in my last post. It makes more sense when drawn on paper than put into words. Anyway, here are a couple of pics that should give you a good idea of how to present the gouge to the wood. Beyond that, it's a matter of feel, how level the gouge is relative to the floor, and how much it is rotated into the wood. Note the thumb is placed in the flute, so as not to push forward, the fingers curled over the top of the gouge in order to push it straight down onto the tool rest, rather than into the wood, which will result in bouncing. The tool is guided 90% by the right hand, with the bevel tangent to the bowl surface. Adjustments need to be smoothly made by the right hand in order to achieve a fair curve, and avoid dips or ridges. This is the hardest part of mastering the cut, but you will have instant feedback by the gouge if you start going astray. You can easily take a 1/8 very clean cut with no tearout in just about any wood if all goes well.

I'll try to get some more pics next time I get to turn, which may not be until Monday, that will show the gouge position in mid cut. Maybe Stuart will have some more info up by then too. If you can swing, it, I think you will get a lot out of the video. It's pretty entertaining too, they have a great give and take, good natured ribbing, and are obviously enjoying themselves. The camera work could have been better, but it's enough to get you going.

Dan

[Fred Belknap]

Dan sure appreciate your help and the pictures and explanation really help. I have basically the same set up as you and I see what you mean about the handle being blocked by the tailstock. I normally do the outside first while it is attached to the tenon so the headstock would limit the push cut somewhat. I'm assuming that you do the inside before you attach the bowl to the vacuum, I use the Holdfast system and sometimes in certain woods it doesn't work that great so use for finishing the bottom only and that with the aid of the tailstock. I did resharpen the 1/2" Sorby gouge freehand and man does it get a sharp cutting edge. The push cut is one I use mainly on the inside and sometimes on the outside bottom third going from the top toward the bottom. This thread has given me a lot to ponder on as I am always trying to cut down on sanding and do a better job. Thanks and I will be checking out the video.

[Lloyd Butler]

Great photo angle Dan.

If you watch the chip come off the tool, it is being sliced a bit by the nose angle. If you have a lot of tear out, try lifting the handle to make that bevel angle more vertical and slow down the forward motion of the tool. This will increase the slicing action of the nose. If you want to remove a bit more wood with each cut, drop the handle a bit to open up the slicing angle on the nose and the chips will fly.

To get the smooth outer shape with this cut, it really helps to be in the correct position before the cut so that you can just swing your body along the cut and keep the tool handle tucked into your side so that your body helps to absorb the cut. If you try and free hand the tool not tucked in, then you need to have very good motor control in your arm to make the entire cut without "facits".

Lloyd

[Gerry Jensen]

I recently switched from an 8" grinder with a Wolverine system to a belt sander system (e.g. AAW Journal, December 2012, Vol. 27 - No. 6), which has eliminated the concave bevels on my tools. I'm getting better cuts, tools sharpen very quickly, and I am wasting a lot less steel.

[Dan Forman]

Great photo angle Dan.

To get the smooth outer shape with this cut, it really helps to be in the correct position before the cut so that you can just swing your body along the cut and keep the tool handle tucked into your side so that your body helps to absorb the cut. If you try and free hand the tool not tucked in, then you need to have very good motor control in your arm to make the entire cut without "facits".

Lloyd

You can tuck in when doing a pull cut, but not with the beginning of the push cut, the bed of the lathe will get in the way; it requires a much greater arc to go from foot to rim than the pull cutdoes. The next set of pics will show this, when the piece is still mounted on the faceplate, and no tailstock is needed. Stuart says to begin, make sure your body is properly aligned for the end of the cut{where you can be relatively tucked} (at the rim), then you have to reach out as far as necessary to reach the beginning (foot of the bowl) where you are decidedly untucked. He advocates long tool handles for this reason, they will give you better control when arms are extended away from the body. They will also allow greater control when the business end of the tool needs to go a greater distance beyond the tool rest. Longer handle gives greater leverage. Another advantage not mentioned, with a longer handle, it takes greater hand movement to make the point of the tool to move, which allows for a smoother surface.

Dan

[Reed Gray]

It took me a year or two to figure out what was so 'wrong' with Stuart's push cut method. I took a 3 day workshop with Stuart and Allen at Nick Stagg's place. Now, by wrong, I mean it wasn't how I turned bowls. I can remember with my first lathe, a 4 speed Atlas, that my back would get sore. When I stepped up to the PM 3520A, part of the reason was because of the sliding headstock. Perfect! Slide it down to the tailstock end and turn off the end, and then, it turned into a bowl lathe, and I could stand up straight and not have to bend over. Stuart's method of push cut and holding his handle arm extended out away from his body is an adaptation for turning on a long bed lathe to allow you to stand up straight and not have back pains. You will never see some one do this type of turning with a Glaser/lead shot filled handle. I would think that the deltoid/shoulder muscles will burn a bit when you first learn this cut. If you want to hold the tool handle closer to your body on a long bed lathe, then this is when you use the pull cut. It drives me crazy to see turners who have pivoting headstocks or sliding headstocks that don't use that feature when turning bowls. With the headstock slid down to the end, I can do push cuts on the outside of the bowl without the bed of the lathe being in the way. I may have to straddle the legs a bit when coming around to the side of the bowl, but that is a minimal problem.

I don't consider concave vs flat on the bevel makes any difference. Think of it this way. On the outside of the bowl, a convex surface most of the time, the bevel contact is only at the cutting edge. On the inside of the bowl, a concave surface most of the time, in order to cut with the bevel contact near the cutting edge, you have to grind off the heel of the gouge, because otherwise, the cutting edge is a long way from the heel of the bevel. Straight of concave bevel shape would make no difference. Now, with a skew, that is another story.

robo hippy

[Wally Dickerman]

What a great thread. So far the talk has been about the Batty and Mahoney systems of turning with the bowl gouge. I started using a bowl gouge in the early 80's when just about nobody really knew how to use one. It started with Peter Childs in the UK in the late 70's. Actually, Jerry Glaser was making one earlier than but it wasn't marketed.

I have a hard time understanding all of these wing angles etc. I have developed the grinds that I like and that work for me for many years. I do measure the nose angles. I use a 60 deg most of the time with a 5/8 gouge. I have a 1/2 in with a 45 deg that I use a lot. I also like a 3/8, also with a 45 deg nose. Wing angles? I have no idea. Actually, nearly all of my turning is HF's.

I was fortunate that Richard Raffan came to Seattle in the late 80's and spent a month or so. I got to know him and watched him turn quite a bit. I learned a lot about various aspects of woodturning. He was using a 45 deg. fingernail grind for most of his bowl turning. He grips the tool not far below the ferrule for most of his turning. I copied that and still grip the tool that way. If I'm roughing some large bowls I do grip it farther back and use a gouge with a weighted handle. Richard also got me started using a screw center. (the 4-jaw chuck didn't exist then). I still use a screw chuck a lot and so does Richard.

If I'm not turning between centers I do a lot of my turning on the outboard side of my Oneway. It helps a great deal to be able to face the piece from the end of the bed. Using a push cut I can tuck the handle for the whole cut. Those who have lathes with sliding headstocks and don't take advantage of this don't know what they're missing. All of my hollowing on HF's is done facing the piece regardles of what tool I'm using. Very easy on my aging back.

The masters all have their styles and grinds for bowl gouges. Raffan, Ellsworth, Jordan, Batty etc. all are different. I do think that it's a good idea to use one of them as sort of a model. Most of us eventually develop our own style and have our favorite tool grinds. The important thing is using the tool and getting the most out of it.

Just about none of you guys can remember the dark ages before the bowl gouge. Long and strong scrapers reigned supreme. Hollowing tools weren't marketed so you had to make your own.

[Dan Forman]

Here are some more pictures which may help to clarify things.

First is a push cut, shows the direction of force mainly toward the edge of the bowl, and showing that it's actually cutting into side grain, rather than end grain, which is why it leaves such a clean surface. This is a cut that I stopped to take the picture with the same gouge. Note that the tool is presented at a relatively shallow angle relative to the lathe bed. There is no difference in technique between a roughing cut and a finish cut, other than usually using a smaller gouge and taking a lighter cut, but the angles/forces are the same.
http://i98.photobucket.com/albums/l279/T-Caster/DSC_1002_2.jpg

Contrast with a pull cut, with the gouge held at the usual 45* angle relative to the lathe bed. The shaving taken will come more from above the edge than in front of it, meaning that end grain will have to be cut, which is why the resulting surface won't be as clean in most cases, especially with wood such as this elm, with coarse, interlocked grain. This cut is the same pictured above, not made by a pull cut.

http://i98.photobucket.com/albums/l279/T-Caster/DSC_1004_2.jpg

This one shows that the cut is almost 1/4" deep, and still clean. http://i98.photobucket.com/albums/l279/T-Caster/DSC_1007_2.jpg

And this is a macro of the end grain left by this relatively stout cut. See any tearout?
http://i98.photobucket.com/albums/l279/T-Caster/DSC_1006_2.jpg

More later.

Dan

[Dan Forman]

Wally --- I haven't tried this at the end of the lathe yet, but to keep tucked, and work all the way around the bowl in one cut would seem to require some pretty fancy footwork in order to maintain a ridge/dip free surface, whereas using a long handle and working away from the body at the beginning of the cut will prevent you from having to move the feet. Each would seem to present different challenges to a single, smooth, continuous cut from foot to rim.

Dan

[Hayes Rutherford]

Dan, now that you have the push cut down you can combine the two methods and in one motion. form the chuck spigot, pull cut the flat spot for the chuck jaws, pull cut a base , then start to pull the bottom curvature of your vessel, then roll the gouge and swing the handle around and go into the push cut and finish the outside curvature. You are actually scraping when you start the cut but that gets you around the problem of starting a push cut at the base.

[robert baccus]

I finally caught on here. You guys were talking about the tailstock getting in the way of your handle and I couldn't get my head around that. No wonder--that gouge cuts both ways you know. I always cut toward the"holding", and downhill if possible. You got boocoo room if you cut the outside or inside towards the bottom. I thought this was standard practice but maybe not. Wally, I remember those days--I think I bought the first DB gouge in Texas. I smiled for a week after that yeah. Suddenly I had to use a rake and shovel in my shop. Dan, try a super sharp 3/8 DB gouge on your final cuts with the bevel rubbing--light, fast rpm cut???

[Reed Gray]

Dan,
For your push cut (photo 1) you are using a 'traditional' gouge, which is ground very similar to a spindle roughing gouge. Rolled onto its side, you get a high angle shear cut and a long 'sweet spot'. This is a different cut than if you use the 40/40 gouge rolled onto its side.

For your pull cut (photo 2) if you try to cut with the flutes pointing up, you are really doing a scrape cut, and that one would be very grabby. For the pull cut, you need to drop the handle, and roll the flutes over to 90 degrees, or sideways. That way you are getting a bevel rubbing cut and a fairly high shear angle. If you roll it over some more, you have a 'shear scrape' as in high angle shear cut with no bevel rub.

robo hippy

[paul vechart]

"Warning - this is not the same cut as Lyle Jamieson describes when he talks about push cut in his Youtube video. "

Dan you mensioned above about Lyle Jamieson's push cut not being the same as the push cut you are talking about. I watched Lyle's u-tube videos and would like you to tell us the difference in the push cuts if possible. I just bought a new Sorby bowl gouge...it came with a 45° bevel. I used the push cut on the outside of the bowl and it really does leave a very smooth finish. Before that I was using an Ellsworth gouge with a 60° bevel angle and the finish was not as good. I know they were two different type gouges but maybe the 45° bevel is that much better than the 60°. Good thread going here!

[Dan Forman]

Dan,
For your push cut (photo 1) you are using a 'traditional' gouge, which is ground very similar to a spindle roughing gouge. Rolled onto its side, you get a high angle shear cut and a long 'sweet spot'. This is a different cut than if you use the 40/40 gouge rolled onto its side.

For your pull cut (photo 2) if you try to cut with the flutes pointing up, you are really doing a scrape cut, and that one would be very grabby. For the pull cut, you need to drop the handle, and roll the flutes over to 90 degrees, or sideways. That way you are getting a bevel rubbing cut and a fairly high shear angle. If you roll it over some more, you have a 'shear scrape' as in high angle shear cut with no bevel rub.

robo hippy

Reed --- It's the same gouge in both pictures, a 40/40 grind - it only looks like a traditional gouge in the push cut photo because of the angle of the photo - the nose of the tool seems to be foreshortened, but it's still there. I just wanted to show how the wood was being cut, and that was the best angle to show it, but you're right, it does look like a traditional grind.

In the pull cut picture, I just was trying to show how it would cut the wood coming down on the edge from above, more than the push cut takes from in font of it. Hope that makes sense. Because I took the pictures one right after the other, I just laid the gouge on the gap left from the push cut. Had I actually done a pull cut, then showed the gouge in the position that cut was made in, it would have looked a little different, rolled over on it's side a little more to rub the bevel, but I figured everyone would already know that one. Hope that clears up the confusion.

Dan

[Dan Forman]

I finally caught on here. You guys were talking about the tailstock getting in the way of your handle and I couldn't get my head around that. No wonder--that gouge cuts both ways you know. I always cut toward the"holding", and downhill if possible. You got boocoo room if you cut the outside or inside towards the bottom. I thought this was standard practice but maybe not. Wally, I remember those days--I think I bought the first DB gouge in Texas. I smiled for a week after that yeah. Suddenly I had to use a rake and shovel in my shop. Dan, try a super sharp 3/8 DB gouge on your final cuts with the bevel rubbing--light, fast rpm cut???

DB gouge = dedicated bowl gouge???

I get much better surface working out from the foot, than working in from the rim. I will use the latter sometimes for gross shaping, but can still get tearout from it. I was wondering why you couldn't see the trouble, it was pretty obvious to me. :)

I use an American (D-Way)1/2 gouge for the final cut, which would be the same as a 3/8" English gouge. I do speed up the lathe for it, but sometimes the roughing cuts have a better surface, as I have nowhere near mastered this yet. I am steadily improving though.

Dan

[Dan Forman]

Dan, now that you have the push cut down you can combine the two methods and in one motion. form the chuck spigot, pull cut the flat spot for the chuck jaws, pull cut a base , then start to pull the bottom curvature of your vessel, then roll the gouge and swing the handle around and go into the push cut and finish the outside curvature. You are actually scraping when you start the cut but that gets you around the problem of starting a push cut at the base.

Hayes --- I don't really "have it down" yet, but working on it. The attraction of doing it all in one go is not having the blend the two cuts, though that will probably happen on occasion. and can always be done if circumstances demand. I am reasonably flexible that way, but still trying to get the pure approach down too. Kind of like learning the melody before improvising, going back to musical analogies.

Dan

[Dan Forman]

"Warning - this is not the same cut as Lyle Jamieson describes when he talks about push cut in his Youtube video. "

Dan you mensioned above about Lyle Jamieson's push cut not being the same as the push cut you are talking about. I watched Lyle's u-tube videos and would like you to tell us the difference in the push cuts if possible. I just bought a new Sorby bowl gouge...it came with a 45° bevel. I used the push cut on the outside of the bowl and it really does leave a very smooth finish. Before that I was using an Ellsworth gouge with a 60° bevel angle and the finish was not as good. I know they were two different type gouges but maybe the 45° bevel is that much better than the 60°. Good thread going here!

Paul --- Stuart defines a push cut as one in which all of the force actually directing the cut or path of the gouge comes from the right hand pushing the gouge from the foot of the bowl to the rim. The left hand only holds to tool on the rest, it doesn't guide it in any other way. If you look at Lyle's cut, (for the outside of the bowl) he is pulling the tool with his left hand, which by Stuart's definition would be a pull cut. . This is only for the outside of the bowl, there is no pull cut on the inside, only push.

Stuart's version of the push cut is shown below. You stand back behind the bowl, the gouge is primarily guided by the right hand pushing out to the rim, the left hand only holds the tool down on the rest, not pushing into the wood, which would cause the tool to start bouncing. If you feel the bounce, you know you are doing it wrong. Thats the instant feedback I was talking about earlier. The shaving is primarily taken by the nose, not the wings, and the cut is into side (face) grain, no end grain. The pull cut alternates cutting side and end grain. Tearout often results when cutting end grain.

The pics I posted this afternoon were closeups, and didn't show the operator, so I hope this one will clear that up. It's awfully hard to show everything you want to when using delayed shutter, so I wasn't able to get the nose of the tool in the picture. By the way, I don't claim to be at all expert about this, just going on what I learned from Ashley Harwood, who was a student of Stuart's, and from the video :Two Ways to Turn a Bowl, by Stuart Batty and Mike Mahoney. The video is highly recommended, and explains all of this in depth. For all I know, Lyle's could be considered a push cut, but doesn't seem to fit Stuart's definition. If you look at the way Lyle cuts the inside though, that does fit: left hand pushing the tool down on to the rest, right hand guiding the direction of the cut.

http://i98.photobucket.com/albums/l279/T-Caster/DSC_1015_2.jpg

Dan

[Dan Forman]

Is it just me, or is the Creek a little goofy tonight? Anyway, this was a double post, so please ignore.

Dam

[Reed Gray]

I did a push cut for years and used both hands till I saw Chris Stott at a demo for our club. He started a cut on the inside of a bowl, dropped his left hand, turned around and started chatting with our club. Huge eye opener. The thing with the 2 handed cut is I don't think you 'feel' the wood like you do when the left hand only rests on the shaft. We all know that bump that happens, both inside and outside the bowl when the bowl goes out of round. Use less pressure on the drive hand, and less 'grip', and most of that bump smooths out.

robo hippy

[robert baccus]

Sorry--I was referring to a US true 3/8 DB--deep bowl gouge. I find better support for the gouge(especially on thin wood--less chatter) cutting toward the hold and downhill if possible. For one thing I am not in a contortion position dodging the tailstock. If I do my part I get perfect cuts and if I can anyone can. Like Wally I bought a DB gouge before I knew what it was supposed to do and was purely self taught. I'm about to get over that handicap but I can say I know all the wrong ways to cut wood. Love this thread--how about another DAn.

[Dan Forman]

Robert --- Stuart has some very interesting bowl gouges coming out in the next couple of months - parabolic flute, and laminated with 10V on top for a long lasting edge. They are milled from beam shaped stock (higher than wide) for extra support. Ashley had a couple of them, and I'm going to pick some up when they are ready. Ashley recommends a parabolic (eliptical) flute, in between a U and a V, but with continually curving sides rather than straight like a V. She says a U has too wide of a nose for a 40/40 grind to work well, would be too aggressive. The D-Way gouges that I have are closer to a U than a V, but have the straight sides of a V. I think a slightly narrower nose would be easier to control, and parabolics are easier to blend the edge when sharpening. For reference Sorby bowl gouges have a parabolic flute. Here is a link to the Batty gouges: http://www.woodturning.org/sbw/wp-content/downloads/gouges-info-consumer.pdf The usual disclaimer, I have no connection to Stuart Batty.

I guess I'll have to try the rim to foot cut, but like I said before, I often get tearout in that direction when initially shaping a roughout.

Dan

[Grant Wilkinson]

This is great information, but some of it leaves me confused. Robo, you said that the Batty grind cannot be achieved with a jig. I don't understand why not. As I read Stuart's picture, you could place a gouge with the flute flat on your grinding platform, set at 40 degrees, and grind the 40 degree sweep. Then, you could place the gouge flute up on your platform and grind the nose to 40 degrees. Then, using a wolverine/varigrind or some other similar jig, you could turn the bevel on the wings. You would set the length of the wolverine by placing the gouge in the varigrind, and the varigrind in the pocket of the wolverine, then moving the wolverine "bar" until the nose angle that you ground on the platform lined up with the wheel. I appreciate that the angle on the wings would vary depending on where you had set the arm on the varigrind, but the 40/40 would be intact. I don't see anywhere in Stuart's pic where he talks about the ideal angle for the wing, only the angle for the sweep.

If I am wrong, and that's entirely possible, I would be grateful if someone could explain why. I'm not arguing the merits of the 40/40 over the 45/45 or any other angle, merely trying to understand why they cannot be achieved with a jig.

[Reed Gray]

I am not totally clear on that either, one would think it was possible, but Stuart and others who use this grind claim that it is so. Mostly I don't think the gouge rolls properly to the side when you attempt this grind. I don't even have a gouge jig any more, so can't attempt to grind it both ways and see what the actual difference is. You grind flutes down at 40 degrees, roll it over, and grind away the flat. There is commonly a line scribed into the platform so you know where 40 degrees is.

robo hippy

[Grant Wilkinson]

Tks, Reed. I've seen how Stuart and Mike do it, using the lines drawn on the platform. I had not heard that they say it can't be done with a jig. It's too bad that Stuart has not been back to this thread, which he started. He could, no doubt, clear up my confusion.

I've played with the 40/40 and 45/45 grind by hand for a while to see how I would get on. I tried the 45/45 using the Varigrind. It was obvious that the wing angle was not the same. However the 45 degree nose angle remained, and the 45 degree sweep angle did, too. (I ground them on the platform before putting the gouge in the Varigrind.) So, if Stuart is, in fact, saying that his grind cannot be duplicated with a jig, I have to conclude that he is referring to the wing angle, which, he does not mention at all in any of the videos that I have seen, or in the post that starts this thread. It's easy to see how that angle could affect the cutting style, though.

Tks again, Reed.

[Reed Gray]

I am thinking that the reason it can't be duplicated with a jig is that the jig does not roll over far enough and the bevel on the wings is more vertical which would make the wing rather thin. When hand rolled, You get a more blunt angle, and more heavy duty wing.

It has been a while, but I seem to remember that Stuart used his gouges with the flutes more up/vertical rather than rolled onto the side. That would give a higher shear angle when cutting. Problem with that is that it didn't take much to wander over onto the high side of the wing, which makes the tool unbalanced, and I would get catches. I always have the gouge rolled onto the side.

I have tried the 40/40 angles, and just didn't care for them. It made the gouge too pointy for me. I prefer a more open flute, a rounded nose, and rolled over.

robo hippy

[Dale Miner]

I am thinking that the reason it can't be duplicated with a jig is that the jig does not roll over far enough and the bevel on the wings is more vertical which would make the wing rather thin. When hand rolled, You get a more blunt angle, and more heavy duty wing.

It has been a while, but I seem to remember that Stuart used his gouges with the flutes more up/vertical rather than rolled onto the side. That would give a higher shear angle when cutting. Problem with that is that it didn't take much to wander over onto the high side of the wing, which makes the tool unbalanced, and I would get catches. I always have the gouge rolled onto the side.

I have tried the 40/40 angles, and just didn't care for them. It made the gouge too pointy for me. I prefer a more open flute, a rounded nose, and rolled over.

robo hippy


In my mind's eye, the 'higher shear angle' from a straight up flute is not apparrent. As the flute is rolled over on it;s side, the final cutting of the fibers occurs more and more at the bottom of the flute. At a full rolled or 'closed' flute, the final cutting is done with the very bottom of the flute and that portion of the edge is in the full shear and no peel position. A bowl bottom, or bottom feeder grind with a consistent beverl angle used with the flute straight up has the highest shear to my way of thinking. Much easier to control though if rolled over about 30 degrees to prevent the top of the flute from entering the wood.

Like you, I prefer a more generous radius in the bottom of the flute and the flute rolled over to about 45 degrees. With the flute rolled at 90 degrees, or fully closed, the all shear and no peel presentation makes taking anything other than a very light cut impossible. Makes a great cut though.

I have no idea what angle my gouges are ground at, but the angle between the tip and the wing is just barely acute from 90 degrees and as such the gouge can be used to make a square corner for chucking in straight jaws.

I attended a full day demo by Stuart and his explanation of grinds and angles. He seems to be knowledgeable about the various factors affecting cutting action and grind angles, but for me, it was to precise. Most edges are able to cut if near to a 45 degree angle. In that demo, Stuart promoted a push cut only for the outside of bowls. However, in that demo Stuart did not use tailstock support when roughing the outside of bowls. He mounted between centers, cut a mortise in the bowl face on one bowl, and used that mortise to cut his tennon and OD rough sans tailstock support. I use tailstock support for roughing the outside and cutting the tennon and use a pull cut for a portion of the OD and cutting the tennon.

Also, spent a day in a hands on with Mike Mahoney. I think Mike and Stuart use similar hand grinds. As I understand it, the advantage of a hand grind aside from being quicker, is that the edge angle is consistent from tip to end of wing, and is less prone to come off the bevel when using a straight up flute. Mike had most of the students regrind to his grind, but left me to my own devices. Hmmm.......

Both Stuart and Mike are very good demonstrators and I would recommend them.

[Mike Cruz]

Okay, am I the only one not drinking the Cool-Aid here? I mean, yes this is informative. Yes, the OP has a point.

BUT, as I started reading this, a couple things hit me... The title suggests that the OP is asking a question. No, it is fact/information that he is giving. This was posted pretty much right after the OP became a member. He not only has only 4 posts, but never responded to the thread again. And as I was reading, the all important message of the thread seemed to come through... He invented a gismo to measure the angle. AHA! Looked like he was trying to sell his gismo.

THEN I noticed this was an 8 month old thread...and the OP STILL hasn't responded to the thread. Very suspect to me... Now, that said, again, very informative. And you don't have to buy his gismo to benefit form the info...just add a few degrees to you bevel angle, and you get the edge angle correct...

[Duane Meadows]

And you don't have to buy his gismo to benefit form the info...just add a few degrees to you bevel angle, and you get the edge angle correct...

In Stuart defence(not that he needs it!)... even he said that in his original post! Also his videos on turning, IMHO, are the best I have seen.

[Grant Wilkinson]

Tks again, Reed. I believe that you are right about Stuart's "jig statement". I've done the 45-45 grind using a platform and using the Varigrind. I can quite easily duplicate the nose angle and sweep using the jig. However the wings are much straighter and therefore narrower using the jig.