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U-shape vs. V-shape

Alex, I assume you are asking about the flute shape? You might have opened a 'can of worms' as each turner will give you a different response. I know it has been discussed to death before (at least on other forums).

For what it is worth, I believe it depend on the type of wood. The more I turn (generally very hard Aussie hardwoods) the more I am convinced that the V shaped bowl gouges ( with a swept back grind) allow you to get into tight spots and the smaller (pointy) tip is more forgiving.
With too large a tip area (on hardwoods) particulally if you are turning irregular 'ghost' pieces you are only looking for trouble. I find a 1/2" bowl gouge can often cope with a catch but a tool with a larger size tip can be very dangerous. Yes a V shape can clog more, but generally not a problem for me. At least that is my findings thus far. Time and tool technology might prove otherwise.

So, in short it depends on who you ask and what type of wood they use and the type of work they do. If that is any help.
 
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I like and use both. Generally, I'll use the V on the outside, or in the cases Glenn mentioned with voids or hard wood where I don't want to necessarily take a wide bite. I like the U shape (with a rounded heel) for the inside of bowls, especially smaller ones.
 
What it boils down to is the U can be used as a gouge with better effect, and the more parabolic - a true V would be a nightmare - grinds back to a near chisel-straight edge. Which is why the folks extol its abilities on convex surfaces.

I'm a plunge and roll type when hogging, so I like good shaving ejection. Narrow parabolic flutes don't have it. They will fold the shaving and clog if you get too aggressive, rather than ejecting it. Broad parabolic flutes are pretty much the same as "detail" gouges.

Plunge and roll. http://s108.photobucket.com/albums/n28/MichaelMouse/?action=view&current=HollowTwo001.flv

A real large-radius gouge with a uniform grind can be worked all across the bottom of its gigantic U, making continuous shavings which eject right with almost no fold. I prefer this to the narrower U where there's maneuver room, because it gives me a broader skew to the cut. View of a 1/2" gouge with the profile of about a 4" U. http://s108.photobucket.com/albums/n28/MichaelMouse/?action=view&current=CherryPeelIn.flv

On wet wood the shaving is continuous, folding itself against another barrier, as seen here, rather than back on itself to eject.

At least on the smaller 1/4 or 3/8 flute diameters, I'd go U.
 

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Alex,
This is personal preference driven by the grinds folks use on their tools.

Within the Vee gouges there is range of shapes.
The More u shape like the Packard, Henry Taylor are better suited for the Ellsworth style grind and in my opinion for the Michelson grind.

In the Ellsworth you get a beefier shoulder on either side of the nose to use in shear cutting with the more U shaves vee. I get a more uniform bevel from a U shape flute with the Michelson grind as well.

From my teaching experience it is a bit easier for students to get a good profile on the U shape tools. The V shape have so little metal at the tip that it takes a bit more practice to not grind a concave.

Folks who cut primarily with the wing of the tool often prefer the steeper v shape tools and almost no curve to the wing. But maybe they cut with the wing because the tool they prefer doesn't cut well on the shoulder of the nose.

Happy turning,
AL
 
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hockenbery said:
The More u shape like the Packard, Henry Taylor are better suited for the Ellsworth style grind and in my opinion for the Michelson grind.

In the Ellsworth you get a beefier shoulder on either side of the nose to use in shear cutting with the U. I get a more uniform bevel from a U shape flute with t he Michelson grind as well.
Click to expand...

I could be wrong on this. I believe the JoHannes Michelsen tool is the Thompson "V".
Not all the U and the V are the same. The depth of the flute affects the efficiency of chip ejection.
I have posted some pictures from the molds of the flute shape of various bowl gouges as in post #9 in:
http://www.aawforum.org/vbforum/showthread.php?t=4901
 
I love the V shape. I just take my time when grinding the nose to keep it round. It really all depends on the sharpening method you use. I've seen U shaped gouges with really thick grinds at the wings and I've seen them with thin grinds. The same is true of the V. I think it has to do with the angle you choose on the sharpening jig as well as the length of the leg and the nose angle. All work together to change the side grind. The U and the V then also add to this.
If you are doing a Stewart Batty grind or traditional grind the U shape is better.
I don't have as much problems with a gouge clogging so the shape for that reason has never been an issue.
 
hockenbery said:
The More u shape like the Packard, Henry Taylor are better suited for the Ellsworth style grind and in my opinion for the Michelson grind.

In the Ellsworth you get a beefier shoulder on either side of the nose to use in shear cutting with the U. I get a more uniform bevel from a U shape flute with t he Michelson grind as well.
Click to expand...

Doesn't Ellsworth use V shaped flutes? And Mr Jordan as well?
 
Alex,
This was discussed recently (again) on another forum. By far the greatest majority of folks seem to prefer the V shape, but there is considerable variation of that shape among manufacturers. My old Sorby, which for years I thought was a U, is actually what I would call a "moderate" V, as compared to a BB gouge (that I do not like) which is a much sharper V. My Thompson U is more like a C, and is good for inside bottoms of bowls and shear scraping the outside, but not so good for tight inside curves where the sides of a bowl meet the bottom. Note that I turn mostly dry wood, and wet wood is typically more forgiving. The concensus of that other thread was that if you could only buy one bowl gouge with the best versatility, the choice would be a Thompson V. Having used the U now, I realize I should have bought the V.
 
Steve Worcester said:
Doesn't Ellsworth use V shaped flutes? And Mr Jordan as well?
Click to expand...

Steve ,
I suppose all flutes with with slanty sides are "vee"s.

I call the "vee" with the wider bottom curve "U" to me those are more U shaped than Vee.
The profile on the Taylor tool is sort of a rounded vee more U than Vee especially at the bottom of the flute.
Contrast that with the Glaser gouges which have a much tighter curve in the bottom.

I would say Ellsworth is closer to U and Jordan is closer to Vee

I'll edit my first post to make it clearer

-Al
 
Then to confuse matters more there is the Superflute. I think of a U shape as one done with a standard radiused mill. The superflute is a sort of opened up U. Kind of V shaped but with a more pronounced U at the bottom.
 
Maybe Gordon Seto could post the wax castings of different flute shapes. Most flute shapes on the market today are V shape, Jordan, Michelsen, Grumbine and Clewes are some who use this shape I manufacture the tools for these professionals but they are slightly different for each pro... they all want a different way the tool handles for there turning styles which changes with the flute shape. This is interesting but gets very deep, not only do you have flute shape but different included angles and depth of the flute which changes how the tool handles. The Ellsworth is a parabolic (oval) and Stu Batty a U shape.

What the flute shape does is change the way the tool is ground... grinding follows the flute shape to keep the cutting angles. If you look at the flute shape then look straight down at your grind the shape will be close so a V shape flute will have a small nose radius and a U shape flute will have a large nose radius. A U shape flute can't be ground to a V shape or visa versa because you loose your cutting angles... this is the reason for the deep flute on a bowl gouge to have a cutting angle that drives the tool into the tool rest. Don't decide on a flute shape because it might look like the shavings flow better on one shape over the other decide how you want the tool to be ground.
 
The reason I've asked this question was that I've just watched a David's Ellsworth DVD and got sold on his gouge/grind.
I have Henry Taylor 1/2" bowl gouge. It looks like a V/U hybrid. I ground it with Ellsworth grind but still can't get a nice shearing grind.(I tried it only very green walnut and my walnut is not usual dark color but very "blond")

I wonder if it's my skills, flute shape or wood that won't let me make nice shearing grind.

Thanks,
Alex
 
Alex, I have a few different gouges, and find that I really need to have a couple different shapes for different cuts. I have a packard 2060 ground at about 40-45 deg. with swept wings that is a very narrow V, which although it clogs easily, is great for both hogging pull cuts and fine push cuts when truing a profile on the outside. For inside work, I have a couple at the same roughly 60deg. grind, which are both wide U shaped; the crown ProPM, and P&N SUPAgouge. All are 5/8 (called 1/2" by british mfr's). I don't own one yet, but the Thompson tools are great; the V shape was particularly pleasing to me; its a wide V that doesn't clog, and has more of a cutting edge surface than some gouges. And, you gotta love the powder metal edge holding ability! I find that its easier to get a light shearing cut with a smaller U shaped gouge after my other cuts are done; I don't get bruising withe the smaller bevel hitting the surface, but thats just my experience. Different turners are comfortable with different grinds to be sure.
 
Alex, without seeing anything first make sure your grind is right then try it again. Flute shape has a lot to do with it, the Ellsworth and a V shape flute creates a nice shape wing for the shearing cut.
 
John and Doug,

Actually Stu Batty uses primarily a "V" shape, although there are some differences among tool manufacturers in how much curve and how much straight they use in the V -- or to put it another way, how parabolic is the V .

I like your V tools the best for long flute bowl gouges. I grind them with the "Batty" grind, which is 40 degrees hand-ground on the flutes, and join the tip -- which produces more of a sharp point than a round across the front. I also use push-cutting instead of pull-cutting.

Stu also uses a large Glaser U gouge (5/8 I believe) with a long handle as a "bottom bowl gouge". It is sharpened with a traditional grind, a base angle of 40 degrees, and a variable "secondary bevel" of 50 - 70 depending on the type of wood, size of bowl, etc.


I have only used U gouges when ground traditionally. I suppose you could create a swept-back grind on a U gouge, but it seems counter-intuitive somehow.

Others here are undoubtedly more knowledgeable. I have been told that a modified (parabolic) v shape is the most efficient at ejecting the chips and therefore can take a deeper cut. The Thompson V gouges are comfortable, smooth and because of the 10v steel incredibly long-lasting. Can't do better for an all-around bowl gouge, IMHO.

Dave
 
Alex Ku said:
The reason I've asked this question was that I've just watched a David's Ellsworth DVD and got sold on his gouge/grind.
I have Henry Taylor 1/2" bowl gouge. It looks like a V/U hybrid. I ground it with Ellsworth grind but still can't get a nice shearing grind.(I tried it only very green walnut and my walnut is not usual dark color but very "blond")

I wonder if it's my skills, flute shape or wood that won't let me make nice shearing grind.

Thanks,
Alex
Click to expand...

Usually it has to do with the sharpening. If you are using Davids jig or the Wolverine or Sharpfast and derivatives, it has to do with the time spend with the wheel against the wings.You want a wing that doesn't have a lot of curve to it, flatter if you will. May want to get a gouge already ground as a model and try to duplicate it in your "sharpening situation". There are surprisingly a lot of variables, stick out or protrusion from the jig, height of the gouge off the base as well as angle of the jig, all make a bunch of difference. You could make a thesis out of them.
 
Al,
I would call the one on the left a "moderate" V, and the other a fairly sharp V. Since virtually infinite combinations of shape and grind are possible, one wonders if there is someone out there with a computer 3D modeling program who has a handle on all this. As Steve suggested, maybe a good thesis project for a Ph.D. candidate.
 
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It seems we need a definition on what is a "U" or "V" shape. The pictures are the wax molds of some of the bowl gouges of different brands. The picture of two Benjamin Best are LX230, same model number but two very different flute shape.
 

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Here are some pictures of my gouge. I've some tape on it and painted bevel on it so it's easier to see.
 

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Dave, your right I always think of Stu with a U shape gouge and his grind. I found a roughing depth of 3/8 inch with shavings about .030 - .040 thick is about all the big lathes can take at a medium speed before they bog down... these are the shavings that fly 10 foot in the air for demos. I'm sure with the lathe speed cranked way up so a deeper cut could be made but I'll take an extra pass and keep the RPM's slower.

Alex, your grind is perfect so try a different angle of attack, I would call this flute shape oval, a discription should create a picture of the flute... V, U or oval.

Thanks Gordon, these pictures show many of the flute shapes on the market today.

Alex, I'm going to use one of your pictures as a example, there is nothing wrong with this bowl gouge and the grind is perfect but just to show something. If you look at the center picture the oval (parabolic) flute creates a very slight curved wing, now the grind is the same but were it meets up with the flute changes so the bottom and top half of the wing is slightly different. Personally I don't like the curve so the V shape flute will give you a straight wing that doesn't change from top to bottom.
 
To make things more complicated among those for whom the name is the game, a true V-shaped tool is called a bruzze. It was used for making V grooves in spindle work.
 
Alex,

I can't tell for sure from the photo angles but it looks like the angle may be a bit steep. like 80 degrees instead of 60.

You may also have rolled the tool over too far in grinding.

You can check the griind by hand on a smooth round surface.
Hold the tool against the wood with the flute at about 45 degrees, rotate the wood by hand get a light cut working just off the nose of the tool and roll the tool slowly until the flute is straight up.

If it is straight up and not cutting look closely at the cutting edge an bevel.
If the bevel is rubbing and the cutting edge is off the wood you probably have rolled the tool over too far when grinding.

happy turning
Al
 

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There are steep V like the Glaser, a shallower V like Dougs, the super flutes, Dougs U shape, and other variations like the one that MM uses which I think is a 'continental' gouge also known as a type of roughing gouge. For me, the real difference is the steeper the flute is, the more vertical the flutes will be when cutting. The shallower they are, the more the gouge is rolled onto its side when cutting. The only times the wings are used is if you are doing a shear cut on the outside of a bowl, or if you have the gouge on its side and are hogging off a big wide shaving. Most of the finish cuts use the nose of the gouge, not the wings. The wings can be any size you want, and be swept back either shallow or deep. This depends mostly on how far you roll your gouge when sharpening.
robo hippy
 
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