What wing edge angle do you have on that bowl gouge?

[Neil S]

We are all familiar with the Nose Angles that are formed between the flute and bevel when we grind our bowl gouges…

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Some of us also pay attention to the Wing Relief Angle (or amount of sweep back on the wings) of our gouges…

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Both of those angles are measured in relation to the axis of the gouge…

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[Neil S]

Part 2: What wing edge angle do you have on that bowl gouge?

Less often measured and referred to is the Wing Edge Angle, not to be confused with the wing sweep or relief angle. This is an important angle as it determines how the gouge performs when the wings of the gouge are cutting. Unlike the above two angles, this angle is not measured in reference to the axis of the gouge, but between the side of the flute and the wing bevel…

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Halfway along the wing edge is a good point for measuring the average Wing Edge Angle. When measuring the nose bevel angle we view the gouge at right angles to the shaft tip to get an accurate reading. Viewing the Wing Edge Angle is more of a challenge. We have to take an imaginary slice at right angles through the wing edge at about the midpoint like this…

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The wing edge angle is then viewed as if the tip on the end of the gouge has been removed at that imaginary slice line. By looking square end-on at that imaginary slice we can accurately see the Wing Edge Angle.

Unfortunately most swing arm protractor won’t fit into the flute to measure that angle, in which case some interim steps have to be taken to transfer the wing edge angle to a protractor. I use a piece of stiff card inclined at a right angle to the wing edge along the imaginary slice line. The side view looks like this …

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Something like Blu-Tack can hold the card at that correct angle in relation to the wing edge while finding the Wing Edge Angle. With the card held at that right angle to the wing edge, cut out a recess in the card to match the wing edge profile.

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By extending the wing edge angle lines you can then measure those on a protractor.

In this case we are looking at the wing edge angle on a 40/40 grind, which as it happens also has a 40° wing edge angle. So, what you have in fact is a 40/40/40° grind; 40° nose bevel angle/ 40° wing relief angle/ and 40° wing edge angle. In almost all other cases the wing edge angle has to be measured in the above way to know what it is.

For example, the bowl gouge in the following post has a nose angle of 55° has a wing edge angle of 62.5°…

 

[Neil S]

Part 3: What wing edge angle do you have on that bowl gouge?

... this is the bowl gouge that has a nose angle of 55° and a wing edge angle of 62.5°…

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Note: If we do not measure the Wing Edge Angle with the card square to the wing edge we get an incorrect lower angle reading.

Many of you will also know that you get different Wing Edge Angles on gouges that have the same nose bevel angle but different flute profiles, e.g….

Thompson V with 55° nose bevel angle - 55° wing edge angle​

Thompson/Jamieson V with 55° nose bevel angle - 55° wing edge angle​

D-Way V with 55° nose bevel angle - 40° wing edge angle​

Crown with 55° nose bevel angle - 40° wing edge angle​

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Ellsworth/Crown Parabolic with 65° nose bevel angle - 60° wing edge angle​

Woodcut Parabolic with 65° nose bevel angle - 60° wing edge angle​

Henry Taylor Parabolic at 65° nose bevel angle - 60° wing edge angle​

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Thompson V at 45° nose bevel angle - 45° wing edge angle​

Of course, where there is a difference in the nose and wing edge angles there will be a transition between the two towards the nose.

With platform sharpening the nose bevel angle is determined by the platform angle but the wing relief angle and wing edge angle is entirely in the hands of the sharpener.

With swing leg bowl gouge jigs it is the slide setting that determines the wing edge angle and the swing leg setting determines the nose bevel angle. Within limits, we can make adjustments to the slide setting to get our preferred wing edge angle; closer to the wheel will give a more acute wing edge and further away will give us a more obtuse wing edge.

For example, if I move my slide in by just 10mm with my jig set for a 55° nose angle grind it will reduce my wing edge angle from 62.5° to 40° resulting in a 22.5° finer wing edge, which is a significant difference.

What wing edge angles are you using?

 

[hockenbery]

What I find on the Ellsworth grind with a parabolic flute are
60 degree nose angle
45 -40 degree angle between the nose and the wing - AKA sweet spot where I do push cuts
Also the cutting edge used in flute up shear cut.
30 - 25 degree angle on the wing where I to pull cuts.

when These different parts of the tool are used well not much sanding is needed

i have a little plastic gauge with angled notches i find which notch fits the bevel

 

[dbonertz]

Thanks Neil, very thought provoking. I honestly never paid a lot of attention to it, I just went with what works. You have me thinking about it now which is a dangerous thing, for me. Now I'll be playing with it for a while.

 

[john lucas]

I have tried to understand wing edge angle. The wings on my Thompson V gouge the way I grind it are quite acute. Using the vector jig on the same gouge the wing is less acute. I dont find much difference in how the two handle when cutting but I have chipped the thin acute edge occasionally which is why I'm playing with the Vector grind.
I find the shape of the flute affects the wing edge angle. I have an older Henry taylor u shaped gouge that has extremely acute edge when ground with a longer swept back grind. I changed that tool to a 40/40 looking grind that has much less of a swept back angle and the wings are much less acute.
I have a no name u shaped gouge that has really acute wing. I grind that wing even longer and use it as a pull cut. Cuts like a skew and leaves a really clean cut.

 

[robo hippy]

Makes my head hurt..... I can't remember if I ever considered wing edge angle. Wing bevel angle, yes. I am not really sure if it makes much difference. Some prefer a slight arc in their WEA, some want them more straight, and that seems to hold true for both V and parabolic flutes. If you platform sharpen, then your wing bevel angle is more obtuse/blunt than the jig sharpenings, which are far more acute.

robo hippy

 

[Doug Freeman]

Very interesting subject and one that belongs up there with the thread on flute shapes in terms of importance.

I've paid attention to wing edge angle for quite a few years. It caused me to change up my jig settings to increase the angle on swept back grinds (I use Tormek jigs, so the adjustments are different). I've used gouges ground with Wolverine jigs that have fairly acute wing edge angles, and they are difficult to control in a bevel riding slicing pull cut.

My swept back Ellsworth style gouges have ~45° wing edge bevel, and my 40/40 has ~30°. I may play with the jig/bar settings to see if I can increase the angle on the 40/40. I will have to make a custom tool bar distance gage, I've only been using the TTS-100 A and B settings.

The wing edge angle can also be measured using a protractor - see the image below. Simply divide the measured angle by 2. (demo only - not an actual measurement)

I'm not convinced that V and parabolic flute shapes effect the resulting wing edge angle a large amount (U flutes are a very different animal). For my set up for a long wing gouge, the pivot point of the tool (not the tool projection, though tool projection does change the length of this measurement directly) to the mid wing bevel point is ~2-1/8". At that length, a 1° change in bevel angle would require the bevel contact point to move 0.037". A 5° change would be a 0.186" (3/16") change. These are radius values - if flute width were measured, then double the values. The concept and calculations are the same with a Wolverine setup, but I don't have one to look at.

 

[hughie]

I have tried to understand wing edge angle. The wings on my Thompson V gouge the way I grind it are quite acute. Using the vector jig on the same gouge the wing is less acute. I dont find much difference in how the two handle when cutting but I have chipped the thin acute edge occasionally which is why I'm playing with the Vector grind.
I find the shape of the flute affects the wing edge angle. I have an older Henry taylor u shaped gouge that has extremely acute edge when ground with a longer swept back grind. I changed that tool to a 40/40 looking grind that has much less of a swept back angle and the wings are much less acute.
I have a no name u shaped gouge that has really acute wing. I grind that wing even longer and use it as a pull cut. Cuts like a skew and leaves a really clean cut.

Been there and done some wing chipping myself and so I teamed up with Neil in a discussion wing angles and steel choice. I guess theres more to come.

 

[Neil S]

The wing edge angle can also be measured using a protractor - see the image below. Simply divide the measured angle by 2. (demo only - not an actual measurement)

I'm not convinced that V and parabolic flute shapes effect the resulting wing edge angle a large amount (U flutes are a very different animal). For my set up for a long wing gouge, the pivot point of the tool (not the tool projection, though tool projection does change the length of this measurement directly) to the mid wing bevel point is ~2-1/8". At that length, a 1° change in bevel angle would require the bevel contact point to move 0.037". A 5° change would be a 0.186" (3/16") change. These are radius values - if flute width were measured, then double the values. The concept and calculations are the same with a Wolverine setup, but I don't have one to look at.

Very interesting input there Doug.

I'll look at those measurements on my gouges and jig and see how they correspond.

It is not clear to me at this stage how you have used your protractor to measure and calculate the wing edge angle, but it may be clearer to me when I try to measure that way myself.

 

[Neil S]

I have tried to understand wing edge angle. The wings on my Thompson V gouge the way I grind it are quite acute. Using the vector jig on the same gouge the wing is less acute. I dont find much difference in how the two handle when cutting but I have chipped the thin acute edge occasionally which is why I'm playing with the Vector grind.
I find the shape of the flute affects the wing edge angle. I have an older Henry taylor u shaped gouge that has extremely acute edge when ground with a longer swept back grind. I changed that tool to a 40/40 looking grind that has much less of a swept back angle and the wings are much less acute.
I have a no name u shaped gouge that has really acute wing. I grind that wing even longer and use it as a pull cut. Cuts like a skew and leaves a really clean cut.

Some interesting observations there John.

I find that chipping can be an issue with acute wing edges depending on which type of cut you are using. Acute edge wings perform best in supported slicing/peeling cuts where you drop the handle and ride the wing bevel. I presume you do your pull cuts in a similar way, John.

The wings are doing a different job and are far less supported when doing push cuts and are more venerable if ground to an acute wing edge with that cut. Of course, this becomes more so with hearty roughing push cuts. If you only ever do push cuts with a bowl gouge you would probably be best served by going with a less acute wing edge angle.

Those that do both wing and push cuts with their bowl gouges have to find a happy medium wing edge angle that works for them both ways or go with dedicated gouges for the two types of cuts.

Also, the larger the carbides in the tool steel the more likely they are to break out from an acute wing edge. Larger carbides provide both durability but also a vulnerability if the edges are too acute with some cuts.

Carbides can also break away during coarse grinding if the the wing edge is too acute...

200x magnification​

 

[Richard Coers]

I have whatever the Vari-grind puts on it. But to be honest in nearly 40 years of turning I've never measured an angle on any of my turning tools. Since I can move my hands to adjust to what is there, I've never seen the point. But I've never checked the rpm of the spindle either. Must be my farm training.

 

[Neil S]

I have whatever the Vari-grind puts on it. But to be honest in nearly 40 years of turning I've never measured an angle on any of my turning tools. Since I can move my hands to adjust to what is there, I've never seen the point. But I've never checked the rpm of the spindle either. Must be my farm training.

Richard

When I started turning over 50 yrs ago I set the grinding platform to 45° and rolled the gouge and swung it a bit from side to side and that was it. There have been a lot of developments since then and along the way I have found some things work better for me than others. I can't help being curious and trying to understanding why some things work better than others.

Like anyone who has been turning as long as we have you can adjust to whatever tool is in your hand. We have a turning colleague down our way who would turn with an axe or shovel at demos to prove a point, but back in his workshop where he was making a living he was very particular about his turning tools and techniques.

Likewise, my preference is to adjust the tool wherever I can to work as sweetly as it can for the way I prefer to turn. I have less energy and endurance in the workshop nowadays, so the less adaptation I have to do the better the output and enjoyment for me. But, if I do find a better tool or adaptation to do the job then I will, of course, change the way I turn with that... it's an endless journey.

In recent years I've been passing on some of what I have leaned about woodturning to my grandchildren. Teaching helps focus attention on what, how and why you do things that you have been doing automatically with accumulated experience and muscle memory. Here is my eldest grandchild who is now 16yrs old back when he was turning his first bowls when he was just 3yrs old... . In comparison, I was a slow starter having not turned something properly until I was about 20.

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Apologies for going off topic... back to wing edge angles!

 

[Neil S]

Very interesting input there Doug.

I'll look at those measurements on my gouges and jig and see how they correspond.

It is not clear to me at this stage how you have used your protractor to measure and calculate the wing edge angle, but it may be clearer to me when I try to measure that way myself.

So I gave Doug's method a ago. I set my protractor at twice the known wing edge angle for the following gouges, but couldn't find any correlation to that angle myself. Here are the photos with the protractor set at twice the known wing edge angle...

Thompson V with 55° nose bevel angle - 55° wing edge angle
Thompson/Jamieson V with 55° nose bevel angle - 55° wing edge angle



D-Way V with 55° nose bevel angle - 40° wing edge angle
Crown with 55° nose bevel angle - 40° wing edge angle



Ellsworth/Crown Parabolic with 65° nose bevel angle - 60° wing edge angle
Woodcut Parabolic with 65° nose bevel angle - 60° wing edge angle
Henry Taylor Parabolic at 65° nose bevel angle - 60° wing edge angle



Thompson V at 45° nose bevel angle - 45° wing edge angle

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Unless I missed something there, I think the method I outlined in my previous posts is a more certain method of measuring the wing edge angle, which is the angle formed between the upper inside wall of the flute and the wing bevel.

 

[Neil S]

What I find on the Ellsworth grind with a parabolic flute are
60 degree nose angle
45 -40 degree angle between the nose and the wing - AKA sweet spot where I do push cuts
Also the cutting edge used in flute up shear cut.
30 - 25 degree angle on the wing where I to pull cuts.

Hockenbery

Thank you for those angle measurements .

That is quite an acute wing edge angle, which I expect would give a very nice shear cut and last quite well using that cut.

 

[hughie]

Like most, I have been at this sharpening thing awhile, started out with doing by hand no jig and did so for many years. Weakened and bought a Woodcut jig and have been hooked on jigs ever since, and with this I paid scant attention to wing angles. But branching out into making my own gouge tips in the quest of finding the best steel for our unfriendly hardwoods. Lead me to sourcing other grades of HSS and it became obvious due to edge failure I had to start looking and trying to understand wing geometry. The path has been very interesting and has produced some interesting outcomes. I have found with conventional jigs a lot more individual adjustment of leg angles, pivot point distance along with protrusion distance and so on, noting also the whole project is a work in progress and may well wander off in another directions led me to Vector type plate as the simplest method of individually grinding each wing angle. This is not an attempt to build my own Hannes Vector jig, but rather an acknowledgement of his understanding of wing geometry. So much, so I won't be putting up any images of what I have come up with. Noting again the fickleness of R&D that it could quite readily change direction abruptly.
What I have put up is a very fine grade TCT that I wish I had a full set of as it has proved to be the most effective and durable gouge tip I have