Twice Turning with 40/40

[Tim Tucker]

Here ya go Doug-
Let me know if there is anything else I can do-
T

 

[Lars Hansen]

@Tim: Would you mind explaining the details of your use of the Michelsen fixture for the 40/40 grind? I presume you start finding the correct distance to match the desired nose angle?
Excactly what hole(s) do you then use to get the correct wing angle(s)?
TIA, Lars

 

[Tim Tucker]

@Lars-
The holes furthest away from the grinder are the Lef wing Right wing and nose grind pivots. The center hole that in line - along the same “back row” is the nose grind pivot. You grind the left, then right wing in the left and right most rear pivot holes(or right then left if that is your preference) then “marry” the two with a light grind on the nose using the center hole in that bcak row, swinging left and right only enough to blend the nose and wings.
Then along the center of the plate -inline with the square tube supporting the pivot plate, the next hole forward toward the grinder remove some of the heel. The next hole forwrd is another relief grind so the you have a nice, clean and uniform removal of the heel and now the gouge can get into tighter radiused transition areas without bruising the wood.

 

[Lars Hansen]

@Tim: Thanks, but that sounds much like the recipe for the Michelsen grind? Or do you use a variation of the 40/40 with relief grinds?

 

[Tim Tucker]

The Michelson grind and the 40/40 are as close to the same thing as I can imagine. Even Stuart Batty says that the Michelson is so-

If you want - when using the Michelson platform - you dont have to make the relief grinds, nor do you have to swing the left and right as far - which merely shortens the the wings - again - like the SB 40/40.
The key thing - to me - is the the nose is 40%....and the wings - whether or not they are short or faired back into almost an Irish grind length...are also 40% + -

So - I find this jig improves the 40/40 grind in 2 ways:
1. Consistency. Once you try it and compare it to free-hand platform grinding the 40/40 the difference is clear.
2. Speed. Combining the Oneway Vari-jig with the Michelson platform is an easy decision because most of us have a Vari-jig.
3. Variability of wing length - As above - you can determine whether you want a very short - almost no wing, to a very long wing - or anywhere in between....
4. Relief - Again, consistency. I have freehand ground them and still can. but this will spoil you.

 

[Doug Freeman]

@Tim Tucker Thanks, the pics show me where the pivot points need to be. What angle do you set the varigrind arm at?

 

[Tim Tucker]

@Tim Tucker Thanks, the pics show me where the pivot points need to be. What angle do you set the varigrind arm at?

Will check that when I get back to the shop this afternoon.

 

[Lars Hansen]

@ Tim: Thanks a lot, think I got it now!

 

[Tim Tucker]

My pleasure Lars! Hope that helps. Anything else I can do, pictures, measurements, etc just let me know.

 

[Tim Tucker]

Sorry for the delay…. Pivot arm/gouge holding is right at 30 degrees + -

 

[Donna Frazier]

The Michelson grind and the 40/40 are as close to the same thing as I can imagine. Even Stuart Batty says that the Michelson is so-

If you want - when using the Michelson platform - you dont have to make the relief grinds, nor do you have to swing the left and right as far - which merely shortens the the wings - again - like the SB 40/40.
The key thing - to me - is the the nose is 40%....and the wings - whether or not they are short or faired back into almost an Irish grind length...are also 40% + -

So - I find this jig improves the 40/40 grind in 2 ways:
1. Consistency. Once you try it and compare it to free-hand platform grinding the 40/40 the difference is clear.
2. Speed. Combining the Oneway Vari-jig with the Michelson platform is an easy decision because most of us have a Vari-jig.
3. Variability of wing length - As above - you can determine whether you want a very short - almost no wing, to a very long wing - or anywhere in between....
4. Relief - Again, consistency. I have freehand ground them and still can. but this will spoil you.

You can not vary the wing length of a 40/40 gouge. Stuart Batty's 40/40 grind is a 40degree tip bevel angle and 40degrees swept back on the wings. He says you can use either a V flute or parabolic, but he grinds them differently in order to match the flute shape. On the V flute you can visually see a radical change of bevel angle as the tip transitions to the wing.

To use any grinding jig, requires "skill" in maneuvering the gouge in the fixture correctly, in order to achieve the desired shape. The 40degrees swept back will not happen automatically.

 

[Tim Tucker]

You can not vary the wing length of a 40/40 gouge. Stuart Batty's 40/40 grind is a 40degree tip bevel angle and 40degrees swept back on the wings. He says you can use either a V flute or parabolic, but he grinds them differently in order to match the flute shape. On the V flute you can visually see a radical change of bevel angle as the tip transitions to the wing.

To use any grinding jig, requires "skill" in maneuvering the gouge in the fixture correctly, in order to achieve the desired shape. The 40degrees swept back will not happen automatically.

Sorry to disagree with you Donna, and I do not want to come across as argumentative. So, please don't interpret anything I write as with a hidden agenda, or of intent to be disagreeable.
You absolutely can vary the length of the wing WITH the Michelson platform and the use of a Vari-jig. You cannot do so as easily, or within the ideals of the Batty 40/40 grind via free-hand grinding. While each demonstrator/professional has "their" way of doing something - that does not mean it is the ONLY way to do it. Even Stuart Batty has stated publicly that the Michelson grind is almost the same as his - in term of nose and wing angle. Michelson does like to sweep back the wings almost like an Irish/Ellsworth grind - which is further back than the Batty 40/40 grind. You do not have to with the Michelson jig. It is a choice and up to the individual.
I find the "skill" you refer to in using a fixture for grinding is MUCH less the that involved in free-hand grinding on a flat platform. Moreover - using a jig/fixture will allow much more consistent grinds with less removal or wasted steel.
I have used both side by side. I can grind both free hand and with the Michelson platform and a Oneway Wolverine Vari-Jig side by side. I use parabolic flute gouges. I have several SB Tools gouges, as well as Ashley Harwood parabolics.
But I am also someone that does not fret over 39 or 42 degrees. I think the 40 degrees is a "target" that is what the person selling is a believer in - and that does raise perceived value of "exactitude" above the reality of what you or I will see in practice. When I started turning, I was very concerned that I find the "best" grind and make certain it was always exactly that angle. My mentor - Joe Ruminski laughed at me.p Kind of hurt my feelings....) Butsaid to me....find the angle that works for YOU. One that is efficient, and comfortable with YOUR body mechanics - and stick with it until you are confident with it. THEN you can experiment with other grinds. He was right I think.
I have a theory about the reason for the 40/40 and will not distract from this thread with it, but I might start a separate thread on that. I hope you are making shaving and having fun!
T

 

[robo hippy]

Kind of like Tim says, being off a few degrees doesn't make much difference. Main thing to me is being able to repeat it. Having the 40 degree sweep lines on the platform helps, but isn't exact, and some times I go more to one side than the other. Makes no difference. You can sweep longer or shorter too, and again, no difference. I don't have any swept back gouges any more. No clue about the Michaelson set up. I only use the platform. Took a bit to learn how not to get the bird's beak in the V flutes, and when Stuart first started with his platform he would say that the V flutes didn't work as well as parabolic. Now, he says that you have to sharpen them a bit differently. Main thing is not to spend any time on the wheel just to either side of the center of the flute shape. I had already figured that one out.

robo hippy

 

[Lars Hansen]

Tim wrote: I have a theory about the reason for the 40/40 and will not distract from this thread with it, but I might start a separate thread on that.

Please do. This forum has some very qualified readers who, I'm sure, will be able to "peer review" your thoughts, making all of us wiser.

 

[Doug Freeman]

I have a theory about the reason for the 40/40 and will not distract from this thread with it

Please do start a separate thread. Interested in your theory.

As for 40/40 wings, Stuart states they need to be at 40deg, not longer or shorter (sure +/- a couple of degrees). It has to do with how the trailing wing cuts through the grain. He provides details in a couple of videos I’ve seen. This aspect is lost with a long swept back grind.

 

[Tim Tucker]

Please do start a separate thread. Interested in your theory.

As for 40/40 wings, Stuart states they need to be at 40deg, not longer or shorter (sure +/- a couple of degrees). It has to do with how the trailing wing cuts through the grain. He provides details in a couple of videos I’ve seen. This aspect is lost with a long swept back grind.

And - while that is true for Stuart's perspective....If you watch any of Johannes Michelson's videos or demos on making a wood cowboy hat...he uses that long wing in what I think of as a "suicide" cut.....and very effectively. SO - I think it as the oil design evolution is each has a specific use for the long wing or shorter wing. Great to have choices!

 

[Donna Frazier]

Sorry to disagree with you Donna, and I do not want to come across as argumentative. So, please don't interpret anything I write as with a hidden agenda, or of intent to be disagreeable.
You absolutely can vary the length of the wing WITH the Michelson platform and the use of a Vari-jig. You cannot do so as easily, or within the ideals of the Batty 40/40 grind via free-hand grinding. While each demonstrator/professional has "their" way of doing something - that does not mean it is the ONLY way to do it. Even Stuart Batty has stated publicly that the Michelson grind is almost the same as his - in term of nose and wing angle. Michelson does like to sweep back the wings almost like an Irish/Ellsworth grind - which is further back than the Batty 40/40 grind. You do not have to with the Michelson jig. It is a choice and up to the individual.
I find the "skill" you refer to in using a fixture for grinding is MUCH less the that involved in free-hand grinding on a flat platform. Moreover - using a jig/fixture will allow much more consistent grinds with less removal or wasted steel.
I have used both side by side. I can grind both free hand and with the Michelson platform and a Oneway Wolverine Vari-Jig side by side. I use parabolic flute gouges. I have several SB Tools gouges, as well as Ashley Harwood parabolics.
But I am also someone that does not fret over 39 or 42 degrees. I think the 40 degrees is a "target" that is what the person selling is a believer in - and that does raise perceived value of "exactitude" above the reality of what you or I will see in practice. When I started turning, I was very concerned that I find the "best" grind and make certain it was always exactly that angle. My mentor - Joe Ruminski laughed at me.p Kind of hurt my feelings....) Butsaid to me....find the angle that works for YOU. One that is efficient, and comfortable with YOUR body mechanics - and stick with it until you are confident with it. THEN you can experiment with other grinds. He was right I think.
I have a theory about the reason for the 40/40 and will not distract from this thread with it, but I might start a separate thread on that. I hope you are making shaving and having fun!
T

I never said the wing length couldn't be varied with the Michaelson platform. What I said was that if you dont stop grinding the wing at 40 degrees back and were to sweep the wing further back with the jig, it would no longer be Stuart's 40/40 but would essentially become a 40 degree Hannes grind. (I was trying to say that you can really see the difference between the grinds with a V flute)
Stuart Batty's grind is not the same as JoHannes Michaelson's grind. Both gouges use different technique and tool presentations. They are both great grinds. The 40/40 is a race horse but needs a bottom bowl gouge to finish the race. The JoHannes Michaelson grind is great at percision, curves and finess. I agree with you, Tim, that it is great to have choices. I use both grinds. Having turned a couple cowboy hats with the JoHannes Michaelson grind, I can say that you definately couldn't turn a whole hat with just a 40/40 gouge like you can with that gouge!

 

[robo hippy]

Well, one thing that Stuart and I do the same, and it has been a while since I have seen him, most of the time, we cut with the flutes vertical rather than on the side, and the handle more level rather than dropped. The nose is doing most of the cutting with the wing doing a little of the cutting. On the inside, the handle is almost always level, or close to it. Mike Mahoney does use a dropped handle pull cut on the outsides of bowls so he is cutting more with the wing rather than with the nose.

robo hippy

 

[Kevin Jenness]

Inspired by this discussion I tried out the 40 40 grind again, and this time it clicked. I re-turned a 13" diameter x 4" deep dry cherry bowl and got the cleanest results yet. Thanks to all for the push.

I followed Jeff Smith's advice and turned a 1/8" rabbet just inside the rim to mount the piece on aluminum jumbo jaws (11" minimum diameter) in a Talon chuck. The Oneway chucks can't go far inside a bowl because of the key, so I ordered a set of flat jaws and will make wooden jaws to suit future bowls of different sizes. I suspect a Vicmarc chuck is more versatile here as you can sneak a short hex key inside the rim and locate the chuck deeper with a smaller jaw set. Anyway, the setup worked very well.

On the inside I used the 40 40 gouge down to the transition and finished the bottom with an Ellsworth gouge using the shear cut just left of the nose. I cleaned up some ripples in the bottom with a negative rake scraper, but the top inside was as clean as a whistle once I set up my bowl steady. I don't know how Stuart Batty can turn the inside as he does without a bowl steady - experience helps I guess. By the time I have turned as many bowls as he I will have been dead for 40 years.

I used a Thompson v gouge. I had been sharpening with a platform with decent results once I got over the "birdsmouth" problem at the transition from the tip to the wings. I suspect the v is a little simpler to grind as getting a straight wing is just a matter of laying the gouge in the platform at the appropriate angles. I decided to see if I could set up my Varigrind jig to get the same shape, and for the life of me I could not do it with one pivot point. The wings always had a much more acute angle than the nose.

I decided to try mimicking the Michelson fixture, so I cut a v channel in a block of wood and mounted to the underside of the Wolverine bar, opposite the pocket so I could use both. After a bit of experimentation I found some hole locations , jig angle and blade projection that worked to match the 40 40 grind I had copied from Batty's videos. I'm not sure how much time it will save but it was an interesting exercise.