Flute Profiles of Bowl Gouges

Re: Flute Profiles of Bowl Gouges

john lucas

Bare in mind that this is just my opinion and I haven't owned a lot of different gouges. I have an off brand U shaped gouge. When I grind it with swept back wings the wings get a very acute edge. This is fantastic for pull cuts. It cuts very clean because of the handle down sheer cutting angle and the acute sharp edge on the wings. for push cuts when roughing it's not so good. Well it is at first becasue the lower wing will take huge cuts but it dull quickly because of the thin edge. The long acute edge wing is also very good for shear scraping.

Then I have a U shaped Henry Taylor gouge that I grind in the 40/40 grind. For push cuts this tool cuts very clean but because the wings don't fall back as far it's not as good for really hogging off wood. The nose is also very round and because it's ground 40/40 the edge remains same all the way up the wing so you have a much larger sweet spot for that sheer angle push cut. There is also a short edge for shear scraping but not nearly as long as my other tool and you have to be careful where you cut on the edge because it's fairly short. A good all around tool especially if you want clean cuts.

My go to gouge is a Thompson V shaped bowl gouge. I put an Ellsworth or Iris grind on it pretty much the same as Doug Thompson shows in his instructions on how to sharpen bowl gouges. It has a moderately long wing. The V shape gives it a fairly narrow nose so for push cuts you have to keep the flute at roughly the same angle. you can rotate the 40/40 grind open or close quite a bit and still do the same push cut. The Advantage of the V is the wings are thicker giving you a less acute edge but a very strong long lasting sharp edge. Great for roughing bowls because you can cut the full length of the wing and it holds that edge for a long time.

I have another short gouge tip that I made for experimentation. It is a U shaped gouge and I've ground it kind of like a spindle roughing gouge with the wings almost straight up. I use that with the flute almost straight up. Being U shaped the wings have a more acute edge than the nose and used straight up the wood crosses the wing at a very sheer angle. Couple that with thin sharp edge and you get a very clean cut. Using the gouge this way also puts very light pressure on the bevel which reduces chatter on thin bowls.

Here is a photo of those 4 tools. Ignore the spindle gouges on the right. Top tool is the homemade U. Next is the Thompson V, then the no name U, bottom is the Henry taylor.

Re: Flute Profiles of Bowl Gouges

lyle Jamieson

I use a parabolic flute because of the versatility. I can do everything with it. The other flutes have limits. They work fine for many applications but require multiple tools to do what I do with only one tool. I have a real keep it simple approach. The grind shape is important, some are aggressive and some have a more friendly sweet spot and are more forgiving. There is a ton of conflicting information out there, it is hard to sort through it all. Any gouge will work if you learn the rules if the cuts.

Re: Flute Profiles of Bowl Gouges

Reed Gray

There are so many different variations, and combined with how you use them, you get still more variety. I do prefer more open flute designs. This is mostly because when doing finish cuts with gouges, I tend to hold my gouges more level, and use the nose rather than the wing as my primary cutting surface. The more open flute and more blunt nose shape leaves a bigger sweet spot. These types of flutes are ) shape like the old continental style gouges more used for spindle work, a half round and/or U shape, most parabolic shapes. With the V shapes, because the nose is smaller, they work better with the dropped handle and cutting more with the wing than the nose. If you use the dropped handle method, then the more swept back designs are also better so you can get a higher shear angle in your cut. Some of the U flutes do not take the swept back wing profile very well. There are way fewer deep V flutes now because if the V is too pointy at the bottom the flutes clog up very fast.

robo hippy

Re: Flute Profiles of Bowl Gouges

Don Stephan

Following this discussion with great curiosity. Along with the different flute shapes, how much variation is there between manufactures within each flute shape? Or are all U shaped flutes in the same bar size essentially identical, V, parabolic?

Re: Flute Profiles of Bowl Gouges

John C Lucas

No. There is no standard that i know of. I have 4 u shaped gouges all 1/2" and one 5/8" none of them have the same U. The thickness at the bottom and sides vary so e en though the U is more or less a U when you grind them with the same wolverine jiv setting the grinds look different.

Re: Flute Profiles of Bowl Gouges

Bill Blasic

Lyle I'm interested in what cuts you can do with your tool that I could not do with either my Thompson 5/8 V or my Thompson Deep 5/8 V, just curious.

Re: Flute Profiles of Bowl Gouges

lyle Jamieson

My Parabolic shape is deeper and wider than all the others. Again for the versatility and bigger sweet spot for bevel support.

Re: Flute Profiles of Bowl Gouges

lyle Jamieson

They are all slightly different. Makes it difficult and confusing, and frustrating.

Re: Flute Profiles of Bowl Gouges

lyle Jamieson

In my teaching there is only 4 cuts, push, pull, scrape, sheer scrape. Only four things a sharp edge will do when you put it against the wood on a lathe. Two out of the four cuts are more difficult with the "V" shape rather than the parabolic shape flute. The tip gets pointy and more aggressive with push cuts on the V gouges. It started with the Glasier tools way back 30 years ago. With the parabolic flute, I tilt my side grind angle "in" more than most. This leaves the tip pointy. It also gives me a larger radius around the heel of the bevel for more support and friendlier sweet spot with the push cut.

The second cut that is more difficult with the V is the pull cut. I use bevel support with my pull cut. The wings in the V become rather flat and the tip is very aggressive in a pull cut mode. The wings on the parabolic flute has a more rounded shape.

The "U" shape flute becomes problematic in the scraping modes. The U flirts with the 90 degree rule of scraping. The parabolic flute is a guaranteed no-catch scraper if you obey the rules.

What kind of wood?

John K Jordan

You might state what kind of turning you are doing - green or dry. Someone told me recently his V gouge wasn't working well, clogging with shavings. He was turning soft green wood aggressively.

I personally have had no issues with any cuts I've made with my Thompson V gouges. I turn mostly dry wood, some soft like cherry and walnut, some very hard exotics. I seldom turn aggressively.

Those are little details many (or most) people forget to mention when they describe their experience with a tool or method. Sometimes it makes a difference.

JKJ

Re: What kind of wood?

John C Lucas

Im with Nohn and Bill on this one. I do 90 percent of my turning using my 1/2" thompson v. I do lots of pull cuts on the outside of bowls and mostly push cuts on the inside. I.really dont know of a cut i cant do.with my V. I do play with otber tools a lot to try a d learn but almost always go ba k to the v tool

Re: What kind of wood?

lyle Jamieson

To Both Johns, you are both correct. The V works. I have depended on the parabolic flute gouge so long I would have a hard time using anything else. It works for me. You have to admit both your skill levels are ahead of the crowd. You guys could turn with a pipe or screwdriver.

Re: What kind of wood?

Don Stephan

A parabolic gives me the best results inside a bowl, except when I need a bottom feeder. Can't remember if that one is a U or V.

Re: What kind of wood?

lyle Jamieson

It is the tip angle that makes it a bottom feeder. Any flute will work. In fact that is what I recommend to do with the non-parabolic flute tools. Make them, save them, for specialty uses like the bottom feeder.

Re: What kind of wood?

Reed Gray

I frequently use one of Doug Thompson's Fluteless gouges for my BOB tool. ) nose profile, 70 degree bevel, and most of the heel ground off. A deep V like the old Glaser gouges would not work. I roll them over almost to 3 o'clock...

robo hippy

Re: What kind of wood?

John C Lucas

My bottom feeder is a Hunter #5. It has an outside bevel angle of 82 degrees so the tool handle is almost straight out. This enables you to do very steep.sided bowls. The cutter is cupped however and the cutting tip.is around 30 degrees so it cuts as clean as a skew, assuming the skew has a 30 degree included angle.

Re: What kind of wood?

John C Lucas

It kind of boils down to the tool you get used to. You simply learn how to use it when you use it enough. I borrowed an Ellsworth bowl gouge from a friend once to try and learn what all the hoopla was about. It was OK but i didnt see any real advantage over the V Gouve i was used to using. There were some subtle differences just like any tool.but nothing that would make me throw away the tool.i was use to.using. im.sure if that was what i started with i would love it and probably swear by it.

The one down side of the Thompson V tool was pointed out by Glen Lucas at a demo I saw. There is apparently a very slight change in the shape near the bottom that can cause a dip in the edge when sharpening. It never caused a problem for me because i would simply grind very lightly when going past this area. Looking from the top of the tool.its about 1 oclock and 11 oclock. He said beginners have trouble sharpening and get a dip in the edge. He is right. If you use the same pressure all the way around the tool that an happen. Just to see how it cuts i purposely ground it so there is a dip. I could not see that it caused a problem when a tually using the tool. It creates a more convex grind on the remaining part of the wing and still cuts well.when doing deep push cuts and works just fine for pull cuts or shear scraping. The edge isnt as pretty as a smooth flowing curve but i could not tell that it caused any problems.

Re: What kind of wood?

Bill Blasic

John what Glen Lucas points out is not a tool problem but a grinding problem. Any number of tools including Lucas's will develop a problem if not ground properly. You have to remember his job is to sell his tools and saying that what tool would you pick to point that out? Of course you would pick the best selling tools available. If you are making your living selling yourself and your products you have to have your own shtick to give yourself a selling point. I believe that at some point in your turning adventure everyone realizes and can tell the what's what about all of this. Now I've said this before as I have done probably 35 or 40 hands on with the best turners in the world and I have never seen one of them while instructing say I cannot use your tool because it is not parabolic or what ever. They may have to sharpen it but they use the person's tool like they used it all their life, they are pros that know how to turn. And finally like yourself I have no problem with a dip on my Thompson tools.

Re: Flute Profiles of Bowl Gouges *LINK*

Mike Stafford

Love your grind pictures particularly the profile images.

Noticed that you didn't include a picture of the Glenn Lucas 2" long wing grind that he uses for roughing green bowls. Three passes and he is done....

By the way, when Glenn is turning bowls like this the screams from the wood are a bit frightening.


Roughing a bowl in three easy passes...

Re: Flute Profiles of Bowl Gouges

john lucas

Mike I did have a tool like that. I developed a grind with the left wing very long for doing pull cuts on my mirrors. That was before we had reverse on our lathes. I used it handle down and the flutes have a very acute edge. By doing a pull cut with that long edge I could get a very clean surface that required little sanding. When I went to my first AAW symposium where I demoed I met a Black Turner who's name escapes me now. He pulled up a gouge and said "I'll bet you've never seen one with a grind like this" I pulled mine out and had a similar grind. turns out we used it the same way. His also had only one wing ground back.

Glen uses it in a sort of push cut sort of way. Starts out as a pull and then turns into a push which is what I do also but with a much shorter wing. Some of the woods I use would stall a lathe if you took that big of a cut. Glen obviously knows what he's doing and what the wood will handle.

You are correct Bill

john lucas

I looked at the flutes of my 2 V gouges under 20x maginification. There are no flaws, dips, or defects in the flute. In honesty I don't remember if Glen said there was a flaw. He did talk about the V gouge having a problem with dips and maybe I interpreted it as a grind flaw because i have that problem in one of my homemade tools that is a grind flaw. It is obviously something in the way we grind going from the nose to the wings that can easily cause that dip. I completely reground 2 off brand V gouges for another turner the other day and he had really deep dips at almost the same location. His tools had a much sharper turn at the bottom of the V than Doug's do. Perhaps the tendency for beginners to get that shape from V tools is what Glenn was talking about.

Re: Agree

lyle Jamieson

Yes, Bill, they all work. some have advantages and some have obstacles. The differences are very slight but there are differences.

Re: Agree

Reed Gray

That little scallop in the wing near the nose is, as said, a sharpening problem. It is one I address in my platform sharpening video I did earlier this year. When sharpening that transition area on a gouge, you have to roll it over faster at that point rather than keep the same roll and pressure that you can use if you have a half round flute shape like a spindle roughing gouge.

That long swept back edge works on gouges. Though I don't do production work any more, I could match that speed of cutting with my Big Ugly tool. It takes the right wood, and Glenn mentions this under comments on that video. With the scraper, you don't take a pass down the side, then come back to the top, You sweep back and forth and the cutting edge doesn't come off the wood. Yes, I am kind of different....

robo hippy

Something not mentioned is that......

JamieDonaldson

....the Thompson V flute is not as "tight" at the cutting tip as the original Glaser and P&N gouges. This slightly wider tip eliminates some of the clogging problem noted with the other V flute shapes, making it more suited for turning wet wood without clogging the flute.