40/40 Grind Using the Varigrind Jig?

[Dennis J Gooding]

The so-called “40/40 grind” (or sometimes “45/45 grind”) has received quite a bit of attention lately. It is usually described as a platform grind in which the platform is set to produce a nose angle of 40 (or 45) degrees and in which the sharpening involves swinging the gouge alternately 40 (or 45) degrees to the left and right of center while smoothly rotating the gouge on its axis such that the flute points approximately outwards at the end of each swing.

It occurred to me that this grind can be matched exactly at the nose and the outer points of the wings, at least, using a Varigrind jig. Furthermore, the grind will progress smoothly between these end points, whether or not it matches exactly that produced by direct hand rotation of the gouge. To achieve this, one merely needs to adjust the arm angle of the jig so that at the ends of the swings, the shaft of the gouge is at an angle of 40 (or 45) degrees with respect to an imaginary line between the pivot point of the jig and the tip of gouge. To achieve a 40-degree angle using a 1.75-inch gouge protrusion from the jig, open the arm angle half-way between the fifth and sixth notches. To achieve a 45-degree angle, set the arm angle half-way between the sixth and seventh notches. Small variations from the 1.75-inch protrusion would have negligible effect on the required arm settings.

Bear in mind that, as in all free-hand or jig-aided sharpening approaches, the results obtained depend only in part on the rules followed or the jig settings used. How long you grind and where you grind will determine the final result.

 

[Bill Boehme]

May I move this to the Tutorials and Tips forum?

 

[Dennis J Gooding]

May I move this to the Tutorials and Tips forum?

Sure, if you like.

 

[john lucas]

I did exactly that many months ago Dennis. someone was asking if you could do it with the Wolverine and I went to the shop and took my hand ground 40/40 and played with the settings on my Oneway Wolverine until I got it almost exactly as I hand ground it.

 

[Roger Chandler]

I'd sure like to see a video posted where someone did your technique using the wolverine and vari-grind jigs.........perhaps someone with those skills could post one?

 

[Gary Garrett]

I too would like to see a video of this. I have been skeptical of my skill to hand grind the 40/40 but if there's a way to do it with my vari grind I'm all in. I did get my raptor grind setup tools in yesterday and found that on all my settings I was fractions of an inch off and after correcting they all look amazing.

 

[robo hippy]

Well, hard for me to verify as I don't have a Verigrind jig. Biggest difference I can see between platform sharpened and jig sharpened, the jigs will not roll over as far as you can when platform sharpening, so the wings are at a more acute angle than the nose. Roll is what you do when sharpening a SRG on a platform. Sweep is what you do with a round nose scraper. Roll and sweep is what you do with a bowl gouge, lots of sweep with a swept back gouge... Not sure that it really makes a lot of difference.

robo hippy

 

[john lucas]

I'm headed to the shop right now. It is about 80 percent dismantled for my move but I'm leaving the lathe and grinders until last because they won't take long to pack and I might get lucky and can turn something. I will take some photo of the jig if I can find my 40/40 gouge. I have packed most of my turning tools.

 

[Dennis J Gooding]

I'd sure like to see a video posted where someone did your technique using the wolverine and vari-grind jigs.........perhaps someone with those skills could post one?

Roger, I don't have the necessary video equipment and, unlike Robo, the proper cap to wear. However, other than setting the particular arm angle and nose angle, the video would look like any other Varigrind gouge sharpening video.

 

[john lucas]

Here are some photos. This is not a Batty gouge, it's just an older Henry Taylor so the flute shape may not be the same but it works well for me with the 40/40 grind. The flute shape may also affect the wings. I set the Wolverine jig with the moveable arm all the way to the to of it's adjustment. Then I moved my V arm out until it gave me a nose that was 40 degrees. I like a very small main bevel so I put a 1/2" thick nut in the V arm and swung the gouge. this create the secondary bevel. The bottom bevel is done with the tool out of the jig and just hand rotate it across the stone to knock off that sharp edge. This was also done in mad rush so the grind isn't perfect but pretty darn close. I have the tool extended 1 3/4" from the front of the Wolverine and the V arm was extended 6 3/8" but that may only work with my grinder/CBN wheel combination.

 

[Dennis J Gooding]

John, I am a bit confused here. The arm setting you show would yield a swing of of 20-something degrees to each side rather than 40 degrees.

 

[john lucas]

Not sure about that. I simply took my existing grind that I did by hand using the 40/40 technique taught by Stewart. Then I put the gouge in the jig and adjusted things until it matched all the way around. It was actually off by about 1/2mm or less. There was just a hair of light showing on the wings when I rotated it with out grinding. Just took one light pass to on the grinder with my 350CBN wheel to get the grind. If I could have move the bottom arm another 1/8" it would have probably matched the wings perfectly. Of course nothing says I ground it perfectly when hand grinding either.

 

[Dennis J Gooding]

Folks, I finally did it -- I made a mistake in my recent post. Through an error of logic I deduced that a particular setting of the arm angle of the Varigrind jig would produce the same result as swinging the gouge from side to side during platform sharpening. It turns out that I had overlooked another factor in the geometry of the operation that invalidates my conclusion. John Lucas's reply set me thinking so I went to the shop and tried it both ways on the same gouge and suddenly the light dawned. I have no doubt that one can satisfactorily approximate the grind using a Varigrind jig as John said, but the very large arm angle that I proposed is not the way. Sorry for the confusion.

 

[john lucas]

I probably need to borrow someones Stewart Batty bowl gouge and see how close it resembles my Henry Taylor. I've looked at his tool pretty closely and just looked again at the same tool ground by Ashley Harwood and I think mine looks very similar but it was at least a day apart and I can hardly remember what I had for breakfast.

 

[Dave Hulett]

I use a Tormek bench grinding mounting set with the Tormek bowl gouge jig. (I love it by the way) Has anyone set it up to replicate the 40/40 grind?

 

[john lucas]

Dave I don't know how adjustable the Tormek gouge holder is. I can measure the angle on my wolverine and maybe you can duplicate that. I have a tormek but don't have the bowl grinding jig.

 

[Bill Boehme]

In my opinion the Tormek gouge jig offers more flexibility than a Varigrind jig. I haven't tried to duplicate the 40/40 grind yet, but I have done a decent job of duplicating the Ellsworth grind and the Johannes Michelsen grind. The problem that I see with platform grinding the Batty grind is inconsistency of results for the average turner (this doesn't apply if you're Stu Batty or very proficient in platform sharpening). I only sharpen scrapers and tools that have a flat bevel on the platform. Under duress I can sharpen gouges on a platform, but it isn't pretty.

 

[john lucas]

Bill I've only been hand grinding the 40/40 for about a year and don't use that tool a lot. It really doesn't take long to get it right, or at least pretty close.

 

[Tom Albrecht]

Thank you Dennis, and John. After learning it from Ashley Harwood in TN last month I did get some pretty good results using her (Batty's) set up. I tried messing with the Wolverine a bit, but gave up.
The one thing I am not clear on about your adjustments, is what about the distance of the slide arm notch from the wheel? Does that remain the same as with the original 60d?

 

[Mike Johnson]

If you turn on a daily basis you also sharpen on a daily basis which equates to a lot of practice and muscle memory and skilled technique for each of the tool profiles ground regularly. If a person has shaky hands then they will most likely need to use a jig instead of free hand sharpening. I free hand most of my lathe tools but still use a jig when I grind a tool with an unusual profile that I am not used to sharpening.

 

[robo hippy]

The only 'difficult' part of learning to free hand or platform sharpen is figuring out that every thing you do when sharpening this way is exactly what you do when turning. Some people have to have things exactly perfect, but they don't need to be, close works about 99% of the time.

robo hippy

 

[hockenbery]

Free hand is such a poor term.
Almost all sharpening depends on controlling the tool movement with the body and supports from body parts, platforms or bench tops.

I have been sharpening my spindle gouges using a method I learned from David Ellsworth about 25 years ago.

The bevel is on the wheel, the handle is in the tips of the fingers with the back of the hand supported by the top the top of the thigh.
The fingers turn the gouge from side to side and a forward motion of the body moves the the tool up and down the wheel. This allows forming and sharpening the edge from tip to wing end just by moving the body and twisting the fingers and the forward hand centers it on the wheel with the elbow at the side. No platform needed. It is sort of like a moveable and rotating pocket for the the Handle end.
There is nothing freehand about this technique everything is locked in.

 

[john lucas]

Tom I established the V arm distance by simply putting the bevel of the tool on the stone. I had already ground it to 40 degrees by hand using Robo rest tool rest but it could be done by simply putting it against the stone and grinding a little, then measure and readjust the V arm until you get 40 degrees. Mine came out to 6 3/8" but that's using my grind and a new CBN wheel and they may not work for anyone else.

And Yea Al is right. Free hand is a bad term. That sort of defines grinding without a tool rest which I often have to at club meetings when trying to tune up tool for a member. I am of course using a tool rest to sharpen the 40/40 grind. I am just using my hands to swing it but the tool rest is supporting it and giving me the angle.

 

[Bill Boehme]

The so-called “40/40 grind” (or sometimes “45/45 grind”) has received quite a bit of attention lately. It is usually described as a platform grind in which the platform is set to produce a nose angle of 40 (or 45) degrees and in which the sharpening involves swinging the gouge alternately 40 (or 45) degrees to the left and right of center while smoothly rotating the gouge on its axis such that the flute points approximately outwards at the end of each swing.

It occurred to me that this grind can be matched exactly at the nose and the outer points of the wings, at least, using a Varigrind jig. Furthermore, the grind will progress smoothly between these end points, whether or not it matches exactly that produced by direct hand rotation of the gouge. To achieve this, one merely needs to adjust the arm angle of the jig so that at the ends of the swings, the shaft of the gouge is at an angle of 40 (or 45) degrees with respect to an imaginary line between the pivot point of the jig and the tip of gouge. To achieve a 40-degree angle using a 1.75-inch gouge protrusion from the jig, open the arm angle half-way between the fifth and sixth notches. To achieve a 45-degree angle, set the arm angle half-way between the sixth and seventh notches. Small variations from the 1.75-inch protrusion would have negligible effect on the required arm settings.

Bear in mind that, as in all free-hand or jig-aided sharpening approaches, the results obtained depend only in part on the rules followed or the jig settings used. How long you grind and where you grind will determine the final result.

May I move this to the Tutorials and Tips forum?

Sure, if you like.

Folks, I finally did it -- I made a mistake in my recent post. Through an error of logic I deduced that a particular setting of the arm angle of the Varigrind jig would produce the same result as swinging the gouge from side to side during platform sharpening. It turns out that I had overlooked another factor in the geometry of the operation that invalidates my conclusion. John Lucas's reply set me thinking so I went to the shop and tried it both ways on the same gouge and suddenly the light dawned. I have no doubt that one can satisfactorily approximate the grind using a Varigrind jig as John said, but the very large arm angle that I proposed is not the way. Sorry for the confusion.

I changed my mind since this appears to be a work in progress.

 

[Emiliano Achaval]

Here are some photos. This is not a Batty gouge, it's just an older Henry Taylor so the flute shape may not be the same but it works well for me with the 40/40 grind. The flute shape may also affect the wings. I set the Wolverine jig with the moveable arm all the way to the to of it's adjustment. Then I moved my V arm out until it gave me a nose that was 40 degrees. I like a very small main bevel so I put a 1/2" thick nut in the V arm and swung the gouge. this create the secondary bevel. The bottom bevel is done with the tool out of the jig and just hand rotate it across the stone to knock off that sharp edge. This was also done in mad rush so the grind isn't perfect but pretty darn close. I have the tool extended 1 3/4" from the front of the Wolverine and the V arm was extended 6 3/8" but that may only work with my grinder/CBN wheel combination.

The tip looks too straight. This is a picture from Stuart's hand out.

 

[Russell Karkheck]

May I add my $.02? For the record, I am not an expert turner, but rather intermediate. I DID have the great pleasure of studying with Stu Batty for 5 days in 2017. He was the single best instructor I've ever had - for anything. So my opinion is based on that experience and practice since then. In my view, people may be working too hard to devise a way to use a jig to sharpen the 40/40. There IS a learning curve, both to sharpening and using this tool, but it's well worth the effort. I believe that one can learn to sharpen the 40/40 without a jig with only a moderate amount of practice. The biggest challenges involve understanding what it should look like in the end and, certainly, reshaping an existing gouge. The latter is a little tedious but not at all difficult. I believe that learning to properly USE the gouge after it's sharpened takes a little more time than does learning to sharpen it. The effort will reward you, given the superior finish you can get. Finally, sharpening by hand offers one great advantage: It is fast. That encourages one to sharpen - or touch up - more often, also giving better results. When you have to grab a jig, measure stick out, sharpen, then remove from the jig, you may be tempted to use the gouge too long before sharpening, just to avoid the effort.

 

[john lucas]

I don't find using a jig slow at all. And the best part is you remove almost no steel because it's so repeatable. I'm pretty good at sharpening the 40/40 by hand but probably remove a little more steel than using my jig to sharpen my other gouges.

 

[Russell Karkheck]

I don't find using a jig slow at all. And the best part is you remove almost no steel because it's so repeatable. I'm pretty good at sharpening the 40/40 by hand but probably remove a little more steel than using my jig to sharpen my other gouges.

I'm sure that's true about removing less steel. Although I wonder how big a difference that is. Is the difference microscopic, or substantial? Of course, that presumes a light touch with either method. This is probably a subject for a different thread . . . but I wonder how long a favorite bowl gouge lasts the average turner. Not a production turner, although that would be interesting to know, too. I'm guessing that the production turner's time is more valuable, by far, than the steel. So speed in sharpening would be more important. If, for argument's sake, our favorite unhandled gouge costs $100, what does it cost us to use it, per year? Inquiring minds want to know . . .

 

[robo hippy]

I would be willing to bet that how much metal comes off the tool makes no difference between jig or platform/free hand. All the difference is between beginner who grinds, and 'experienced' who sharpens... Most difficult thing to do when platform sharpening is to set the angles......

robo hippy

 

[john lucas]

Bowl gouges last for years if your good at sharpening. Someone asked that several years ago and I had just purchased a new Thompson 1/2" V gouge to use for traveling. I had purchased my other one when Doug first started selling them. I layed them side by side and I had ground off an inch. I called Doug and asked if he had changed the gouge any since he started and he said no. So in about 5 years of constant use, and it's my favorite tool so it gets a lot of use, I had ground away an inch. That's a pretty good bargain since there is plenty of flute left. So if I get 10 years out of it and it cost $100, $10 bucks a year. Of course it didn't cost $100 and I will probably get more than another 5 at this rate.
I tell people during my demos that the best thing I ever did was to look at my tools as consumables, like sandpaper. They are meant to be used up. Because of that I sharpened more often because I was not longer concerned with how long a tool would last. Sharpening more often taught me to be better at sharpening so now my tools last longer. So not only is my turning more fun because I always have a sharp tool, and my sharpening takes less time and removes less steel. 2 benefits.

 

[Tom Albrecht]

May I add my $.02? For the record, I am not an expert turner, but rather intermediate. I DID have the great pleasure of studying with Stu Batty for 5 days in 2017. He was the single best instructor I've ever had - for anything. So my opinion is based on that experience and practice since then. In my view, people may be working too hard to devise a way to use a jig to sharpen the 40/40. There IS a learning curve, both to sharpening and using this tool, but it's well worth the effort. I believe that one can learn to sharpen the 40/40 without a jig with only a moderate amount of practice. The biggest challenges involve understanding what it should look like in the end and, certainly, reshaping an existing gouge. The latter is a little tedious but not at all difficult. I believe that learning to properly USE the gouge after it's sharpened takes a little more time than does learning to sharpen it. The effort will reward you, given the superior finish you can get. Finally, sharpening by hand offers one great advantage: It is fast. That encourages one to sharpen - or touch up - more often, also giving better results. When you have to grab a jig, measure stick out, sharpen, then remove from the jig, you may be tempted to use the gouge too long before sharpening, just to avoid the effort.

I don't mean to sound pompous, or wealthy, but I have found that the investment in a few identical gouges along with any handle that can easily change tools makes things pretty speedy. (I particularly like this http://www.turnrobust.com/product/tool-handles-robust-collet-handle-system/). I buy the parts and make my own handles.

 

[Alan Dick]

I don't mean to sound pompous, or wealthy, but I have found that the investment in a few identical gouges along with any handle that can easily change tools makes things pretty speedy. (I particularly like this http://www.turnrobust.com/product/tool-handles-robust-collet-handle-system/). I buy the parts and make my own handles.
View attachment 28431

Tom,

Could you share what collet parts you buy and the source?

 

[Bill Boehme]

I'm sure that's true about removing less steel. Although I wonder how big a difference that is. Is the difference microscopic, or substantial? Of course, that presumes a light touch with either method. This is probably a subject for a different thread . . . but I wonder how long a favorite bowl gouge lasts the average turner. Not a production turner, although that would be interesting to know, too. I'm guessing that the production turner's time is more valuable, by far, than the steel. So speed in sharpening would be more important. If, for argument's sake, our favorite unhandled gouge costs $100, what does it cost us to use it, per year? Inquiring minds want to know . . .

My opinion is that the difference in wear is substantial. However, like John Lucas points out we're probably quibbling over peanuts. I've been using a Tormek to sharpen most of my turning tools for about fifteen years and those tools aren't much shorter than when they were new. However, my main reason for using the Tormek isn't to save money on tool wear since I am obviously spending much more than any perceived savings on accessories and maintenance of the Tormek. My real reason for using the Tormek is that it gets my tools sharper.

I have a dry grinder and use it occasionally. I've taken classes from Stu Batty, Alan Lacer and others so I do know how to get a decent edge when platform sharpening, but I realize that my platform sharpening skills aren't up to the level that John or Reed can accomplish.

I would be willing to bet that how much metal comes off the tool makes no difference between jig or platform/free hand....

I accept PayPal.

 

[Tom Albrecht]

Tom,

Could you share what collet parts you buy and the source?

I buy the collet kits from Robust. Just the collet parts, not the handles. Here is the link again:

http://www.turnrobust.com/product/tool-handles-robust-collet-handle-system/

 

[hughie]

I would be willing to bet that how much metal comes off the tool makes no difference between jig or platform/free hand. All the difference is between beginner who grinds, and 'experienced' who sharpens... Most difficult thing to do when platform sharpening is to set the angles......

robo hippy

Yes, absolutely.

 

[Dean Center]

I'm sure that's true about removing less steel. Although I wonder how big a difference that is. Is the difference microscopic, or substantial? I wonder how long a favorite bowl gouge lasts the average turner.

Based on my personal experience, I believe that for Average Joe turners, a jig makes a large difference in how much steel you take off. Once you reach the skill level of the advanced turners here on the forum, not so much. (I also believe that using CBN wheels, so that you can set the V pocket at exactly the same distance from the wheel surface, makes a difference.)

As to how long a gouge lasts, in addition to sharpening technique, it also depends on the types of wood you turn, the type of steel in your gouge, and how often you sharpen. As a result, it seems unlikely that your question has a single answer. John has used 1" of his Thompson V in 5 years. I've used 3" of mine in the same time, even though I use 2 gouges. John is undoubtedly a better sharpener than I and makes fabulous mirrors with nice looking wood. I have made maybe 300 of each rough turned blanks and utility bowls out of dulling woods harvested from local trees, turning chain sawed octagons through the bark to get there. Apples and oranges. Your mileage will undoubtedly vary.

 

[John Spitters]

As to how long your gouge will last is open to so many variables, I’m now on my second Thompson 5/8” 10V gouge, this is my primary go to tool. The first one lasted around 3-4 yrs, with that gouge having turned perhaps 600 bowls average size being 15-16” diameter, when broken down to cost per unit that’s pretty good value, we spend far more on sandpaper.

 

[robo hippy]

For extended tool life, the difference between sharpening and grinding is the difference, not the method. I would think that as we get more experienced, we do a better job of sharpening, just a kiss is all it takes.... The grit of the wheel would be part of that as well. If all I ever did was hone, my tools would all live longer than me.

robo hippy

 

[John Jordan]

Since I don't use a 40/40 grind, I won't offer an opinion on grinding it, though there is nothing inherently superior or inferior about it. I'm a very good freehand grinder/sharpener, but I choose to use the varigrind jig. I timed it once, and to sharpen the side grind gouge that I use, it takes me ten seconds with a jig, about ten seconds without. The difference is the freehand tool has to be inspected-it is possible to miss a small spot, I don't even have to look at the jig ground gouge. I suspect if I really tried, the jig would be even faster than freehand. Also, FWIW, generally I find the CBN wheels lack the feel of a 60/80 grit aluminum oxide wheel and for me seems to require a bit more effort. I do use CBN wheels.

A Glaser jig is even better-I have a couple, but not quite as handy as the varigrind type.

Even if you are a klutz and grind your tool away pretty quickly, it still just costs pennies per bowl.

John

 

[Randy Heinemann]

I'd like to get back to the topic of using the Tormek with its gouge jig to produce a 40 or 45 degree grind on a gouge - specifically a 1/4" gouge in this case. I have tried various settings using the Tormek jig and don't get the profile that seems to be correct. The resulting profile I get seems to be a "modified Ellsworth grind"; not quite the Ellsworth grind but not quite the desired result either. Could someone who has used the Tormek to produce a grind similar to the 40/40 grind post a picture of the result? The Tormek gouge jig is excellent for producing a razor sharp Ellsworth grind but I'm challenged to produce the other correctly.