Traditional grind, Ellsworth grind for bowl gouges......an observation.

[odie]

I suspect many turners never do use the traditional grind for bowl gouges, as it seems the Ellsworth grind has overtaken the current avenues of learning bowl turning. There is neglect for the traditional grind.

In this regard, I consider myself lucky to have been turning with the traditional grind bowl gouge (ie: V arm, and tool revolved around it's axis against the grinder wheel) prior to the time frame when the Ellsworth grind gained the popularity it has today. In my opinion, there are certain cuts the traditional grind does better than the Ellsworth grind.......and, on the other hand, the reverse of this is also true for other cuts. These are two distinctly different grinds, and each has certain advantages over the other for certain specific applications......and, it should be understood that both are the other's equal for certain other cuts.

Here's something to think about: At the point where the bowl gouge, held in the Ellsworth jig, is exactly straight on to the grind wheel, the grind you are getting is EXACTLY the same as the traditional grind, provided the angle of the bevel is the same. So, the significant usefulness of the Ellsworth grind increases, the further away from the center of the flute, at the nose.

If that can be agreed to, then it would be an easy conclusion to note that the traditional grind can do anything the Ellsworth grind can do, as long as the cutting is taking place at the nose, and some small distance to either side.

Now......application for me, as always, is dependent on many things that may not be the same as for other turners, but I did mention my belief that the traditional grind is superior to the Ellsworth grind in certain specific applications. This is what I've concluded:

* Ellsworth grind is superior for outside turning of long graduated curved surfaces on the exterior. For shorter curves, with the exception of extremely tight radius curves (small ground bevel angle), the traditional grind is the better, in that tool control is better through easier manipulation.

* For nearly all bowls, interior cutting is better with the traditional grind, provided the angle of the bevel is suitable for any specific cut. This is not an absolute, as the shape of some large shallow bowls with long gradually sloping interiors may be better served with the Ellsworth grind. (I acknowledge that some turners prefer the scraper on bowl interiors, but for me, the gouge provides the cleaner cut for this particular application.)

Again, there are many things that could change the needs of the moment, both physical shape of the bowl, and individual turning styles.......but, these two observations have been consistently true for me.......

ooc

 

[hockenbery]

Odie,

If one takes very light cuts as in finishing near the nose then the Ellsworth acts much like the traditional.
Other than that it is apples and oranges.

in roughing you have the lower wing cutting wood while the nose is cutting just off bevel. 3/4 inch shavings are pretty routine in roughing with a 1/2 gouge(5/8 bar)
Both inside and outside.

on the outside by dropping the handle you get a shearcut from the wing that is far superior to the traditional gouge.
Almost like moving a skew over the wood. This cut is close to the nose but the nose is not making contact.
This shear cut also allows the bevel to ride right up against the tenon leaving only a tiny area not cut bevel riding.

One of the beauties of the Ellsworth is the shear cut off the nose with the flute up. An advanced cut used on both inside and outside curve.
master this cut, it leaves a wonderful surface. You can make this cut on the outside curve with a traditional gouge but not on the indiside.

Shear scraping is another task where the Ellsworth beats the traditional.

Everyone should have a traditional ground gouge. Or better yet a Michelson ground gouge to compliment the Ellsworth.
I always have a couple 1/4 gouges(3/8 bar) for finish cuts and tight radius. I personally would not put a sidegrind on a gouge this small.

With an Ellsworth gouge and a spindle gouge you can turn any outside shape and leave a very nice surface.

You can get excellent results with a traditional gouge they won't be better than the those with the Ellsworth and often the surface won't be as good as you would get with the Ellsworth. Especially with the flute up shear cuts.
roughing takes a lot longer and for me is less comfortable using a traditional. The Ellsworth just rips wood away in wide shavings with no bounce or pressure on the turner.

Most folks who master the Ellsworth or other side ground gouge never go back.

Work safe
Al

 

[Bill Boehme]

Odie, the grind does not make a great deal of difference to me except for some specific things like shear scraping. I have more bowl gouges than I ought to and they all are a bit different -- Glaser, Irish, Ellsworth, Michelsen, Böhme, unknown lineage, and almost-but-not-quite traditional. All have at least a slight bit of sweep because I don't care for a sharp corner waiting for a false move from me.

It may be a slovenly habit, but I normally just grab another bowl gouge when the one I am using gets dull. I'll stop to sharpen all of them at the same time after I have dulled all of them. Normally, I'll finish a turning before that happens.

 

[Dennis J Gooding]

I agree that there is a place for both grinds, but it seems to me that the distinction is not so much whether it is to be used inside versus outside the bowl but whether the cut is a push cut or a pull cut/scrape. I use both grinds, but find that a pull cut using a side-grind gouge is very efficient in roughing out both the outside and inside of bowls. With care and a bit of experience, a pull cut and pull shear scraping can be used for finish turning of the outside of a bowl. A conventional grind seem a bit better for finishing the inside of a bowl using a push cut, but often I do not bother to change tools. When executing a pull cut, I use either of two methods depending on circumstances. One is a scooping cut with no bevel rubbing that moves wood very fast. The other is a bevel-rubbing shearing cut.

Dennis

 

[odie]

Thanks for the comments, opinions, and critical reviews, gentlemen.......

Further input is solicited......

Al.....Your comment "everyone should have a traditional ground gouge to compliment the Ellsworth gouge" seems to confirm my initial statement and belief that quite a few of today's turners who started in the last decade or so, don't have, use, or have used a traditionally ground bowl gouge. The traditional ground gouge (in my opinion) is greatly under-appreciated, even though it's performance under certain circumstances is superior to the Ellsworth grind.

I am not stating that the quality of the cut is superior, but the traditional shape lends itself to better handling characteristics under certain conditions. Let's face it......If the degree of sharpness is the same, it really doesn't make any difference what the configuration behind that edge is......because, it's all a matter of presentation of cutting edge to wood that makes the difference. What does matter is the shape of the bevel behind the cutting edge can, and does make all the difference in the world for some cuts......because it has better maneuverability, or ability to manipulate the cut, when in the hands of a skilled turner.

I'm in agreement with Bill that there is a significant overlap of capability between the traditional grind and the Ellsworth grind. Sometimes, either will do well......at other times, one will be the better choice between the two.

Dennis makes a good point about push cut vs pull cut.

The Ellsworth grind can often outlast the traditional grind between sharpening, or honing. This is because the cutting edge is longer with the Ellsworth, and if one uses the entire length of the cutting edge with that in mind, he can extend the life of the cutting edge by adjusting the cut to where the edge is sharpest.........

Thank you all.......

ooc

 

[MichaelMouse]

I agree that there is a place for both grinds, but it seems to me that the distinction is not so much whether it is to be used inside versus outside the bowl but whether the cut is a push cut or a pull cut/scrape. I use both grinds, but find that a pull cut using a side-grind gouge is very efficient in roughing out both the outside and inside of bowls. With care and a bit of experience, a pull cut and pull shear scraping can be used for finish turning of the outside of a bowl. A conventional grind seem a bit better for finishing the inside of a bowl using a push cut, but often I do not bother to change tools. When executing a pull cut, I use either of two methods depending on circumstances. One is a scooping cut with no bevel rubbing that moves wood very fast. The other is a bevel-rubbing shearing cut.

Dennis

You could push and shear/skew any time, in or out if you think about it.

The edge as the wood sees it. http://i35.photobucket.com/albums/d160/GoodOnesGone/Gouge-Curves.jpg

Keeps everything in front of you at arm's length, uses on the tool rest rather than the tool user for support and will not catch when used above the wood. Doesn't plunge well, though. Need a deeper gouge for that.

 

[hockenbery]

Flute design is another consideration.

The parabolic flute
U
V

The parabolic and V actually get sharpest on the wing off the nose where the angles are sharper.

The concept is a 30 angle sharper than a 40 sharper than a 60

The Ellsworth grind works better on the parabolic flutes.


Work safe,
Al

 

[odie]

The concept is a 30 angle sharper than a 40 sharper than a 60

Someone else can correct me if I'm wrong, but if memory serves me correctly, sharpness is not a product of the angle, but how fine the union of the two planes is. Theoretically, a 45 degree angle can be just as sharp as a 20 degree angle.

Regardless, that is besides the point, and I get your meaning, Al......and, I agree that the smaller angle is usually the more aggressive/useful. There is always the exception to the rule, and in some cases a larger angle is preferred.....not because of it's cutting abilities, but for tool control in a specific application.

I do have one question for you, or anyone who cares to respond. Most all my bowl gouges have the parabolic flute, but I do have a few with the V flute. I've tried every type of grind imaginable on these V flute gouges, and I've just not found them to be as good as the parabolic flute........usable, yes.......just not as good. Is there anyone here that prefers the V flute for any application and grind? If so, I'd appreciate your thoughts on this as to why, how, where, and when they are better than the parabolic flute, in your experience. Thank you.

ooc

 

[MichaelMouse]

Pull cutters will probably favor a V. The stuff doesn't make a full 180 as it is cut and come back into your face, but ejects a bit to the side. Plunging favors the smoother shaving path around the flute bottom so that heavy shavings can't fold and clog operations as easily.

 

[john lucas]

All of my new Thompson tools have the V flute. I do a lot of pull cutting and the V flute gives me a slightly blunter edge than a U flute. That goes back to what you were talking about when discussing the joining of two angles.
With my U shaped gouge the sharpness angle of the U flute wings is sharper than the the same thing on my V. Both cut well but the slightly blunter angle holds an edge longer and on the Thompson gouges which are already good at holding an edge this really works for me.
It also gives a slightly different nose profile which I like. It's a little narrower. I have not had a problem with the tool clogging at all.

 

[hockenbery]

Someone else can correct me if I'm wrong, but if memory serves me correctly, sharpness is not a product of the angle, but how fine the union of the two planes is. Theoretically, a 45 degree angle can be just as sharp as a 20 degree angle.
ooc

An interesting question

acute angles cut cleaner. I equate that to sharper but maybe that is not the correct term

Consider razor blades, knives, scalpels, Very acute angles. The sharpest tools?

Plane blades, Skews, spindle gouges, 30 degree angles. Generally spindle work can begin sanding with 320 and sometimes 220.

Bowl gouge 40- 60 degrees for most gouges maybe an 80 for deep bowls. Sanding of bowl gouge cuts usually beings with 180 or 120 or 220.

I has been my experience that more acute angled tools leave cleaner surfaces.
I always considered this sharper but maybe it is something else.

Al

 

[john lucas]

I believe Odie uses the same terms I use. I like to say sharpness is sort of what grit you stop at. It is of course directly related to sharpness angle. As you said 25 degrees we all consider sharper than 45 degrees
However what if the 25 degree blade was sharpened using 180 grit and the 45 degree blade was sharpened to 1200 grit. Which would cut better?
That's why I use the term sharpness when discussing the tools or techniques to produce a polished surface and the term sharpness angle as the angle the 2 surfaces come together.
Of course it gets more confusing when you discuss flat grind vs convex grind. I have not figured out how to properly measure the sharpness angle of a convex grind. To make it more confusing the Hunter carbide cutters actually have a concave grind on the inside with a flat grind on the outside. I can only guess at the angle of those. I've tried to measure and it's somewhere between 25 and 35. Cuts incredibly well.

 

[Bill Boehme]

Someone else can correct me if I'm wrong, but if memory serves me correctly, sharpness is not a product of the angle, but how fine the union of the two planes is. Theoretically, a 45 degree angle can be just as sharp as a 20 degree angle. ....

I understand what you are getting at, Odie. The intersection of two planes is an infinitely thin line. Although we have a qualitative understanding of degrees of sharpness, it is not a term that has physically quantifiable units of measure. When we talk about sharpness, what are we really talking about ... I think that it is how well a cutting tool performs its intended purpose. The cutting edges on a machine for stamping sheet metal has edges that are near 90°, but a wood carver would not find an edge with such a large angle useful. For hand tools like knives and chisels, the way that they are used is usually slicing something (bread, meat, vegetables, wood ...). For this, the more acute the angle, the better -- up to a point and then it is a trade off between strength and durability of the edge vs its ability to slice through the intended material. The speed at which a cutter moves is also a factor in determining things like the shape and angle of cutters. A 30° bevel on a circle saw blade wouldn't last very long before becoming too dull and wouldn't have the right geometry for feed rate, clearing chips, and cooling.

So, I'll disagree with your premise as I understand it to mean the edge formed by the intersection of two perfectly smooth flat planes does not depend on the angle of intersection for its "sharpness". I don't see that concept of sharpness as especially useful. For me, sharpness means how well does a cutting tool perform its intended function. That's my nebulous definition of a nebulous term.

 

[MichaelMouse]

Presentation.

Back to the analogy of the blade you can draw your thumb across, but can not slide along without slicing yourself. Letting the wood come down the edge slices cleanly because it doesn't have a great deal of lift, which can translate into compression and tearing as the blade becomes dull. If the shavings are "flying" rather than falling, the presentation is less than optimum.

Small sharpness angles have advantages and disadvantages. Advantage in getting low to peel while still having some clearance angle, disadvantage in fragility of the edge. Even with a small sharpness angle, if you get too high a pitch angle - on your skew for instance - the lift exceeds the cut so much that it runs back at you.

Good edge terminology here. http://homepages.sover.net/~nichael/nlc-wood/chapters/caop.html

 

[robo hippy]

I seldom use my swept back grind gouges any more. Maybe I should go back and try them some more. It is probably more due to my turning style rather than the 'usefulness' of the tool. I turn at the end of the lathe (sliding headstock). Most of my roughing is done with scrapers. I hold my tools level with little or no handle dropping. I prefer more open flute designs and really don't like the real V with a pointy bottom at all.

Why don't I use the swept back design? Well, the wings are the biggest difference, and work fine for a shear cut on the outside more than the inside with a dropped handle. With a level handle, you get the high shear angle with the nose, and do most of the cutting there rather than with the wings. I can do all the 'shear scrapes' with my scrapers, which just feel better to me. The wings have no advantage for my roughing cuts as the scrapers just out preform them. I can use any nose profile on my scrapers, but prefer the 'inside' scrapers, which if you look at them are swept back like 1/2 of a swept back gouge.

If you are going through convex and concave shapes on your bowls, a short bevel and a more blunt bevel angle will work better, and again, here I hold the tools level.

V flutes are used more for pull type cuts with the handle down, and the wing being the main cutting surface being used. The nose has a very small area for cutting, and for being held level, it is pretty much worthless for the cuts I use.

robo hippy

 

[hockenbery]

I seldom use my swept back grind gouges any more. Maybe I should go back and try them some more. It is probably more due to my turning style rather than the 'usefulness' of the tool. I turn at the end of the lathe (sliding headstock). Most of my roughing is done with scrapers. I hold my tools level with little or no handle dropping. I prefer more open flute designs and really don't like the real V with a pointy bottom at all.

robo hippy

I don't like the v with a pointy bottom either. I do most of my turning with the handle level to the floor with slight drop of the handle after the cut is engaged. I prefer the parabolic flute which is sort of a V with a U bottom. The nose has a nice rounded profile leading to the wings. A lot of folks like the V and I used on for a while.
The parabolic I find more useful. Gives a nicer shoulder for the flute up shear cuts. These work best for me with the handle near level.

A long time ago most bowl turners preferred scrapers. The advent of the side ground gouge swung the most bowl turners to some version of the side ground gouge.

In the end no one knows how you made it. I'd you enjoy using scrapers, why change.

Roughing with scrapers is too much like work maybe I'm not that good with a scraper.


Be safe

 

[Bill Boehme]

.... and really don't like the real V with a pointy bottom at all. ....

I don't like the v with a pointy bottom either.....

Well, I am glad to hear that I am not the only one who isn't on the v-flute bandwagon. I have a couple gouges with narrow v flutes and I use them when all the others are dull, but they are not my favorites.

 

[Dale Miner]

Well, I am glad to hear that I am not the only one who isn't on the v-flute bandwagon. I have a couple gouges with narrow v flutes and I use them when all the others are dull, but they are not my favorites.

Put me in the "Don't like the pointy V" catagory also.

I think the more pointy the V, the less apt it is to run when making initial contact, if presented anywhere near neutral. A more generous V or U flute will have a greater tendency to run with slight presentation errors. The more generous radius in the bottom of the flute causes a skew like cutting action and in theory a cleaner cut, but the skew like action can cause skating if the point of contact of the edge is not tangent (parallel?) to rotation. As such, the tighter V flutes are less frustrating for beginners in my experience, and more likely a second or third choice for more experienced turners.

My first bowl gouge was fashioned from a piece of 3/4" 4340 with a short flute ground into it with the edge of an angle grinder. That flute was somewhat U shaped. My second bowl gouge was an offshore 5/8" with a pointy V flute. Hated that gouge from day 1. Eventually that gouge was reground into an interior bowl bottom gouge.