Bowl gouge flute shapes

[Jon Murphy]

I understand the basic difference between a "U" and a "V" shaped bowl gouge, but there are so many variations I'm a bit buffaloed when looking at vendor's descriptions and the various reviews on the web. I see "deep flute" and "super flute" and "U" and "V". On a forum I see that the Thompson "V" is a bit more elliptical than the Glazer "V" (I think they mean that the V shape is "pointier" on the Glazer".

Obviously the "U" and the "V" are the extremes of flute shapes (don't think an upside-down capital Omega would work). A true "V" would be unsuitable for turning (although I have several for wood carving). A true "U" should work, although I'm not sure if any of them are.

Another variable in the shape of the flute is the depth - the percentage of the diameter of the gouge (a spindle gouge is about 50%, a detail gouge less and a bowl gouge more).

My question is sort of academic for the time being as I've got lots of life yet in the gouges I have, but I'd like to understand the nomenclature for the future. It seems that the terms "deep fluted" and "super-flute" are historical and that the "U" and "V" are current (with variations as to how "Uey" or "Veey" they are, and those by maker). The profile drawings or photos from the maker are almost impossible to interpret. My Ellsworth Signatures from (is it Henry Taylor or Crown?) look almost like my Benjamin's Best from PSI. David refers to his as "super-flute", PSI doesn't bother to describe them. BTW, the Benjamin's Best are great buys for utility gouges that you want to regrind to a purpose. Good steel that holds an edge but cheap enough that you don't mind wasting metal when you want a specialty grind.

Let me emphasize that I'm not asking about grinds, I take care of them myself. Come to think of it, that is why I don't buy tools from some makers who price their factory grind and "simplicity of use" into the product (Sorby a good example). I'm asking about the shape of the flute. If I had my "druthers" I'd buy the tools unground and unhandled (I get half of that from Doug Thompson, but haven't had a need for a bowl gouge from him yet).

Sorry for the ramble, I'm sort of "thinking out loud". I think all my future purchases will be from Doug Thompson or PSI (the former for tools I want to shape, the latter for utility tools I want to re-shape regularly) but I like to understand the nomenclature and the differences. Perhaps there also is a difference in terminology depending on the country.

Best, Jon

[John Keeton]

Jon, I hope you are able to achieve some level of satisfaction in your quest, but I doubt it. IMO, much of the difference in the profiles is minimal and simply an effort by various manufacturers to distinguish their gouge from the herd. I don't dispute that each gouge might have a different "feel." Once one gets past the "V" vs. the "U" (a distinct difference) it becomes a matter of degree, and I think the factors of metal quality and polish (effecting the potential edge quality) become more important than flute profile. While I have my favorites, I also think that given a day or so of turning, I would adapt to any of them sufficiently for my needs. But, then again, I am not a David Ellsworth!

In the end, I guess the only way one will know is own one of each and see what works best for you!! At least, that seems like the only sensible thing for one to do in order to provide momentum for the VORTEX!!

[Thom Sturgill]

I do not know about 'superflutes' but I have U,V and parabolic fluted gouges.
Flutes.png
The last sketch is actually half an oval as it straightens up too much. A parabola, like a V constantly opens, but at an ever changing rate. Each produces a different 'wing' when ground. Ellsworth uses a parabolic and my Thompsons have straight sided V flutes with the Jimmy Clewes model having the tightest radius at the nose.
My U gouges seem to have a very slight vertical side.

I think the 'deep flute' and 'super flute' terms came about to differentiate bowl gouges from spindle gouges.

[John Thorson]

One very visual aspect of these different grinds can be seen in the Thompson Lathe tools site when comparing the V and U flutes.
Type-VGouges.jpgType-UGouges.jpg The V flute grind has a much finer nose profile, compare the nose profile of the 3/8 inch U gouge with the 1/2 inch V gouge in these pictures. The push cut terminates at the nose of the tool. Most of us go from a 1/2 inch flute down to a 3/8 inch flute or even at times to a 1/4 inch flute for finishing cuts. What we are changing when going to the smaller gouges is primarily the nose profile. The elliptical grind / Masterflute grind affect the wing of the tool, it never transitions to a flat wing as in the U and the V which gives you different control options on heavy cuts or when on the wing.

The depth that the flute is ground into the bar stock changes the response of the cutting edge when pivoting the tool on the tool rest. The best way to visualize this is to look at your detail gouge in your spindle tools, it is ground almost at the top of the tool and is very 'quick' to navigate when in use. The normal spindle gouge is ground to about the center of the bar stock. All of your bowl gouges are ground below the center of the tool bar stock to give you the ability to control the cut for those long flowing curves of a bowl. If you grind tool deep into the bar stock you get too much vibration in the tool, more diameter helps here.

This wide variety really is only an attempt to match everyone's style. Often patterned after one famous turner's preferences we get a certain combination of these variables championed by a given manufacturer. In the end you'll have to find what works best for you and it is a luxury to have all of these choices.

[Faust M. Ruggiero]

I think "Deep Flute" is a generic term used to differentiate the gouges ground from round bars from the forged shallow gouges we used years ago."Super Flute" is a name branded by Henry Taylor in the 1970's. The original Super Flute was probably a "U" shaped grind and eventually transitioned into the various grinds we see today. The parabola and the "V" (not really a V) are suitable for all the various swept back grinds we now use. Because the side walls are a continuing and changing curve, we get to use different areas along the grind to do an assortment of cuts with the same tool.
faust

[Thom Sturgill]

Faust, I hate to disagree with you, but I can lay a straight edge along the inside of some of my V flutes and light does not shine between them, while my Ellsworth parabolic is obviously curved.

[Faust M. Ruggiero]

Thanks for the correction Thom. I'm sure you are correct.
faust

[Reed Gray]

Yea, they do make it confusing. Not sure there is really any one answer, but mostly they try to think of a name that will make theirs stand out from the rest. The true differences are minimal. The steel is probably the bigger issue. For tool steel, I prefer the Thompson and the D Way tools. You are buying from the guys who actually make the tools. Other than that, more open flute designs tend to work a bit better held more level, rolled on their side, and cutting more with the broad sweep of the nose. The steeper the sides, the better they work with a dropped handle and shear cutting with the wings.

robo hippy

[Jamie Donaldson]

There is no industry standardization for flute profiles or definitions of same, so each brand shape is determined by the milling tools and practices of the makers. The Thompson V flute is midway between the tighter V of Glazer/P&N, and the wider/more rounded U of the Sorby/Oneway/D-Way gouges, and I like the compromise as a "universal" user. The V has a smaller cutting area at the tip than the U, and some variations of the walls of the flute create different shapes and difficulty in grinding swept back wings.