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40/40 grind

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I recently attended a demo by Stuart Batty and he showed the 40/40 grind done free hand. He mentioned you could come close with a Oneway Jig system. Can anyone recommend a publication or video that demonstrates using a Oneway Jig system on an 8 inch wheel that comes closest to the pure hand done 40/40 grind.

I'm sorry to say I'm too shaky to grind free hand and need stabilization to grind my tools.
 
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You might do better than you expect, Dave. You have the platform to hold the tool at the correct angle. The main maneuvering is to keep the flute parallel to the platform but the whole time, the tool is pressed to the platform. It's very different from trying to grind a spindle gouge freehand the way Bonnie Klein et. al do where they completely leave the platform (or don't even use one). Tom Wirsing figured out how to grind a slight flat on the sides of his gouges so that he could start them out on their sides and swing to the middle and stay right at 40 degrees all the way. Perhaps someone here knows how he did that?
 
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It has been a while, but I am pretty sure that Stuart rolls the gouge as he swings it from side to side. Took a 3 day work shop with he and his dad some years back. I know Ashley Harwood uses the same grind, and now trying to remember again.... The 'traditional' grind, I think is one where you just roll the tool, but there is no sweep to it. If the flutes don't roll on Stuart's grind, the wings get really thin. Ashley only sharpens from the left side of the grinder. This is because she only had the gouge on her right side. I use both right and left, so can turn and sharpen on either side.

The most difficult part of platform sharpening is setting the angles. Every skill you need, you use when you turn. Still trying to get my platform sharpening video final editing done....

robo hippy
 
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Oh, it didn't translate to me..... I use a half round piece of wood with a free swinging needle in the center to demo this. Same thing with cutting, the part that is cutting or being sharpened is directly on the tool rest. The needle swings as you roll the tool.... Need to get the sharpening clip done.....

robo hippy
 
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I recently attended a demo by Stuart Batty and he showed the 40/40 grind done free hand. He mentioned you could come close with a Oneway Jig system. Can anyone recommend a publication or video that demonstrates using a Oneway Jig system on an 8 inch wheel that comes closest to the pure hand done 40/40 grind.
I'm familiar with how Stuart does it, does anyone know how to come close using a Oneway Jig?
 

john lucas

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I will go out to the shop right now and try to figure it out. I have a gouge that has the 40/40 grind so I should be able to play with the Wolverine system and see if I can make it work.
 

john lucas

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OK here is what is really close. I set the leg on the wolverine jig so it's on the first notch as seen from the handle side of the tool. The tool is extended 1 3/4". I adjusted the V arm to give me a 40 degree angle on the nose. I didn't grind my tool but it's really close to matching the 40/40 grind I already have on the tool. This is with a Henry Taylor 1/2" U shaped bowl gouge. hope this helps.

Stewart grind wolverine.jpg
 

Bill Boehme

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Great work, John. I also went into the shop to play around with setting up the Varigrind jig, but I don't currently have a bowl gouge that has a grind that is exactly like the 40/40 grind. Anyway here are some general guidelines for setting the Varigrind:
  • According to Doug Thompson you can come reasonably close to duplicating any shape grind that you want using a Varigrind by first adjusting the Wolverine arm to get the desired nose angle and then adjusting the protrusion of the gouge from the Varigrind to get the desired wing shape. He says that the leg angle of the Varigrind can be just about anything.
  • Here is the way that I go about it which isn't nearly as fast as the way that Doug Thompson would approach it, but I think that it gives you a wider range of adjustments.
    • First I start by setting the Varigrind arm to 45° which is the middle notch.
    • Then I set the protrusion of the gouge through the Varigrind to about 2" by eyeball
    • Next I adjust the Wolverine arm to match the nose angle of the gouge, or in this case set it to give a 40° nose angle
    • The amount that the wings roll over is adjusted by the protrusion of the tool through the Varigrind ... the longer the protrusion, the greater the roll
    • The leg angle adjusts the length of the wing. A small angle gives a long wing and a large angle gives a short wing.
All of these adjustments interact considerably so it will normally take a few iterations to converge on the desired results.

There's one important point that I need to mention regarding the Varigrind or any other jig: The jig only sets the desired angle, but it cannot control the shape of the grind. Controlling the shape is up to you.
 

john lucas

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What I find is the angle of the arm on the Wolverine affects the side grind or the wings. Changing that shifts how far back the wings grind and somewhat how acute the cutting edge is. Then nose angle also changes the wings a little so you kind of have to deal with both. For a while I played with the length of the moveable arm when I was building my own jigs. That didn't seem to matter much unless you were really trying to be exact in matching a grind.
 

john lucas

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that's good to know Dave. Next time it needs sharpening I may try using the jig just to see. I've gotten pretty good at hand sharpening that tool now. I use my Robo Rest and have scribed lines on it at 45 degrees to help align the tool.
 
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Thank you both. I set it as you described and it works really well. I too have the robo rest and checked and the 40 degree setting is spot on with it. As I gain more confidence I may try to hand sharpen but I'd rather spend my time making things.
 
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I have been watching this thread, closely. My issue is that I started out wrong, and got worse, on a bowl gouge. It ended up with a gouge, right in the tip of the nose. I want to be able to correct it as easily as possible. But, I think it would be very easy to make it worse. Any tips on what to do? I have a Wolverine system, and now I have new CBN wheels.
 
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It ended up with a gouge, right in the tip of the nose. I want to be able to correct it as easily as possible. But, I think it would be very easy to make it worse. Any tips on what to do? I have a Wolverine system, and now I have new CBN wheels.

Can you post a close-up photo of the tool (side angle and top angle)?
 
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I ended up sharpening it, as usual. It took a few times on the 80 wheel, but it eventually came out fine. I didn't do the swept back wings, like Stuart Batty, or Cindy Drozda. I want to soon, though.
 

Bill Boehme

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Another method that I have seen recommended:
  1. First grind the nose angle
  2. Then turn the gouge flute down against the wheel and grind the top profile of the wings
  3. Finally grind the sides of the wings until it just barely intersects the top profile
This method is sort of a last ditch if things are so bad that John's method doesn't work. This method uses up a lot of steel so don't do it if you can salvage the edge following John's video.
 

john lucas

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I learned that method from John Jordan and it's mostly used when you get a new tool and have to establish the wing shape you want. Grind the nose. Draw a line with a permanent marker to show you where to stop once you've ground it with the flute against the wheel. The grind the wings and then blend the wings into the nose.
 
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Thanks for the info. I basically ground, as usua, only very little on the nose. After a few swings, it started to come back to its original shape, and profile. Then I put it on the other wheel, and sharpened it. I'm going to give the 40/40 grind a try, as soon as I get my nerve up..
 
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as soon as I get my nerve up..
Too funny. One of our veteran turners, who produces fabulous, fabulous stuff, took a workshop with ... either Batty or Tom Wirsing... anyways, since he'd been turning for 20 or 30 years, it just plain didn't work out for him. Too different from what his techniques have been all those years.:D
 
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Interesting comment Jamie, at the Batty demo I attended an older man I know said he'd have to forget most of what he believed before. I doubt he did. When you reach a certain age it's hard to go back and start over.
 

john lucas

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At my classes it's the older gentleman who can't seem to grasp bevel rubbing or changing what they are doing. I will rotate the tool in their hands to show them how it cuts clean or with less chatter and as soon as I turn my back I can hear them digging into the wood again. The best student I ever had was a female Nurse. She listened to what I said and then did exactly that and was turning really nice pieces by the end of the class.
 
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Another method that I have seen recommended:
  1. First grind the nose angle
  2. Then turn the gouge flute down against the wheel and grind the top profile of the wings
  3. Finally grind the sides of the wings until it just barely intersects the top profile
This method is sort of a last ditch if things are so bad that John's method doesn't work. This method uses up a lot of steel so don't do it if you can salvage the edge following John's video.

I believe this is a video of what Bill is describing. I was watching it couple of days ago and found it useful.

http://thompsonlathetools.com/sharpening/
 

Bill Boehme

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I believe this is a video of what Bill is describing. I was watching it couple of days ago and found it useful.

http://thompsonlathetools.com/sharpening/

Yep, that's it. It's good for quickly making a big change to the shape of the tool, but it also grinds away a lot of steel so only use it when absolutely necessary.

Doug does a good job simplifying tool grinding to make it easy for beginners to see the how and why of sharpening. But, if you wish to grind to a different shape by using a different leg angle, tool protrusion length, and Wolverine V arm setting that's fine ... everything he says about how to grind still applies.
 

hockenbery

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Another method that I have seen recommended:
  1. First grind the nose angle
  2. Then turn the gouge flute down against the wheel and grind the top profile of the wings
  3. Finally grind the sides of the wings until it just barely intersects the top profile
This method is sort of a last ditch if things are so bad that John's method doesn't work. This method uses up a lot of steel so don't do it if you can salvage the edge following John's video.

This method is the best way I have found to put wings on a new gouge that does not have them.
It also is useful on particularly badly ground gouges.
If you try grinding a wing with out jointing the top of the wing quite you will usually get very thin metal bit of metal sticking up on the top of the wing that bends over instead of grinding off. Jointing the top of the flut eliminates this problem and also gives you the target edge of flute to grind to.
 
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I recently attended a demo by Stuart Batty and he showed the 40/40 grind done free hand. He mentioned you could come close with a Oneway Jig system. Can anyone recommend a publication or video that demonstrates using a Oneway Jig system on an 8 inch wheel that comes closest to the pure hand done 40/40 grind.

I'm sorry to say I'm too shaky to grind free hand and need stabilization to grind my tools.

I know I'm late to the party but haven't been on for awhile and only found this string while updating a handout I made on grinding angles. Regarding Stuart's 40/40 grind I have one more thing to add that hasn't been included in the string. The setting John Lucas described in his post is correct. I don't have the Wolverine Vari-grind with the notches, but I put the setting all the way forward (or back depending on your perspective) - see picture, which appears to be the same as using the last notch as John did. The one thing I have to add, is that Stuart was teaching in my shop last November and ground one of my gouges with his 40/40 grind. I then played around with several different sharpening jigs I have, by coloring the bevel of Stuart's grind with a magic marker, and then rotating the CBN grinder wheel by hand until I found a setting where it contacted the bevel on all areas, front and side. I was unable to replicate his grind on any other jig other than the Wolverine. I now use his grind on almost all of my bowl gouges.40-40 Wolverine setting.jpg
 
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Hi, sorry to resurrect an old thread but thought better to keep all discussion together.

I use the Tormek jigs on a dry CBN wheel - any one have a Tormek ‘recipe’ for 40/40 gouge grind?

Thanks
Simon
 

Bill Boehme

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You could try the 40° setting on the TTS-100 setting jig. I have the older TTS-100 that doesn't show as many settings , but you could try angle = 40°, P = 75 mm, JS = 2, and hole A on the TTS-100. If you don't have the TTS-100 here is a short video showing it being used.

View: https://www.youtube.com/watch?v=hpsxVg8SFF4
 

John Jordan

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I learned that method from John Jordan and it's mostly used when you get a new tool and have to establish the wing shape you want. Grind the nose. Draw a line with a permanent marker to show you where to stop once you've ground it with the flute against the wheel. The grind the wings and then blend the wings into the nose.

Here's a link to the video that shows that. It also shows and makes clear the effect of the angle of the jig and the distance of the arm, its very simple really, though we tend to make it complicated. :D

View: https://vimeo.com/111139564



John
 
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I use the Tormek jigs on a dry CBN wheel - any one have a Tormek ‘recipe’ for 40/40 gouge grind?

Thanks
Simon

Yes I do.You can use the Tormek recommended settings Bill quotes, JS 2, 75mm tool extension, hole A, but I changed it slightly to JS 3, 75mm ext, hole A. I think I made this change to get longer wings. Hopefully you do have the TTS-100, otherwise all of this is meaningless. I have both the SVD-185 and -186, and these settings are the same for both. Which are you using? You can download the instructions from Tormek which have many grind/ jig settings listed.
 
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I got to see Stuart last week, and he has slightly changed how he does the platform sharpening of his 40/40. He used to start on the nose and roll towards the wing. Now, he starts on the wing, and drags/slides it from one side of the wheel to the other, and then rolls it onto the nose, repeat for the other side. I have tried it and after a bit of 'learning' prefer that method. It makes it easier to keep a straight wing rather than a slightly arced one. I still prefer a 45/45, but did grind a couple of my 5/8 bowl gouges to a 40/40, which still seems too pointy to me. One possibility is that my angles on my platform may be slightly off. I did find that with my 45/45, I need to get a 45 degree angle sweep on the wing as the 40 degree sweep just doesn't go well with the 45 degree angle. Not sure why. Nick Stagg will be our club demonstrator this week and I will take mine in to compare Nick's angles.

robo hippy
 
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I watched Nick Stagg last night as he demonstrated for our club. He also uses the 40/40 grind. I have used my platform for a long time and found out I liked the 45/45 better than the 40/40. Well, I took two of my gouges in to compare profiles last night. my 45/45 grind was closer to Nick's gouges than my 40/40. Must have been why I preferred it. The gouge jigs just don't roll over to the side enough to duplicate the hand sharpened grind, so the wings have a more acute angle. Not sure how much difference that actually makes. Maybe when I get my Wolverine system set up, I can compare, but I am in no hurry to do that.

robo hippy
 

john lucas

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I grind a standard Ellsworth grind using my wolverine jig. Then I move the jig forward in the V Slot and grind away all but a few millimeters of the original grind. This gives me a very small main bevel and handles very similar to the grind you get from the Johannes jig. My gouge may not be the same as his so the grinds aren't identical but it's pretty catch free unless you do something stupid.
 
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I looked at the Johannes jig once. I do it free hand. Just roll the gouges around till at least half of the bevel is gone/relieved. Stuart now grinds off all but about 1/8 or less of an inch of the cutting bevel. I don't consider it to be essential to grind off that much on the 40/40 grind. I do consider it more important to grind off almost all of it on the BOB (bottom of bowl) gouges. I saw Christian Burshard demo, and one of his gouges had all of the primary bevel ground off so all you had was the cutting edge. He did that free hand, and said that in theory, it shouldn't even cut. I told Johannes about that and he told me he taught that grind to Christian. I don't use the swept back grinds at all any more.

robo hippy
 
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