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any thoughts on Ron Brown’s 40/40 grind jig?

Discussion in 'Woodturning Discussion Forum' started by JeffSmith, Jul 7, 2020.

  1. Vic Sinai

    Vic Sinai

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    Please pardon my ignorance but could someone try to help me understand. I use a varigrind jig and have a tool to set the wheel at precisely 40 degrees every time. So when I put my tool in straight up and down I think I'm sharpening the bevel at the top to 40 degrees. Then when I roll it over to the sides, I think I'm still sharpening at 40 degrees. Isn't this the same as a 4040 grind? Is there more to it? What am I missing? Thank you
     
  2. Mark Jundanian

    Mark Jundanian

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    Yes your nose angle will be 40*, but the angle on the wing depends on other factors, as well. Most notable is the angle that the leg is positioned.
     
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  3. Vic Sinai

    Vic Sinai

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    Thank you for your answer, but really I'm not smart enough to understand what you mean. For instance what other factors? The leg angle is easily adjusted but how should it be adjusted with a 2 inch stick out? Is that something published somewhere? And I'm still not clear about why the angle on the wing isn't at 40 degrees if I'm set up at 40 degrees. I think I told you I was a moron and if my ignorance irritates you don't worry about it, you wouldn't be the first. Thanks again for trying to help.
     
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  4. Lars Hansen

    Lars Hansen

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    Vic, untill one of the capacities here gives you a better explanation:
    The short answer is no, within the normal range of adjustments to the VariGrind, you always get grinds, that have different angles on the nose and wings.
    That is not a fault but a feature and many of us prefer it that way. I use a 55° nose angle with *much* lower degrees on the wings and that gives me a variety of possible ways of cutting with the same bowl gouge. If you type "Ellsworth" into the search box, you can find a lot of info on that subject.
    The 40/40 is special in that it's "inventor", Stuart Batty, argues that having the 40° angle all the way around has certain benefits, but until now, you would have to hand grind it - leaving a lot of us behind.
    Ron Brown has experimented and found a combination of settings, that makes it possible to use the Varigind after all, and he sells a jig to help getting these (pretty non-standard!) settings right.
    Hope this helps.
     
  5. Vic Sinai

    Vic Sinai

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    "within the normal range of adjustments to the VariGrind, you always get grinds, that have different angles on the nose and wings."
    Thank you. Is that because the nose of the tool is closer to the wheel than the wing, especially the lower part of the wing or are they the same distance away and there are other forces at work?
     
  6. Gerald Lawrence

    Gerald Lawrence

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    This is caused by adjustments in the distance the jig is from the wheel and by the angle set in the jig itself. One adjusts the angle on the wing and the other I think the shape.
     
  7. Vic Sinai

    Vic Sinai

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    Thank you, has anyone ever seen an explanation of how to do a 4040 with just a VariGrind. Is it possible? All I know is the faster and easier it is to sharpen during a project the more often I will do it and enjoy turning. It's really a joy on a freshly sharpened tool. Dull, not so much. Sometimes I try different tools on the same project and if getting back to the 4040 grind set up takes too long, or too many steps, for me, it won't happen. That's I think why I'm interested in all this. And maybe in the end, overall and long term, paying the price in steel and time to learn to do it by hand maybe worth it, or, perhaps a Google search on "4040 grind using only VariGrind" will shed some light. Thanks again one and all.
     
  8. Lars Hansen

    Lars Hansen

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    On Ron Browns homepage he has i video that gives you the info that you need except the distance from the pocket on the Wolverine arm to the wheel.
    If you intend to keep using your VariGrind, his jig is 30 bucks and you're ready to go without experimenting.
    Grinding away expensive tool steel may be a more expensive way to get what you want.
    After the initial regrind to a 40/40, daily use is just as straightforward as your standard grind with the VariGrind.
    BTW: I don't think many turners will regard any 40° grind as an allround one. It has some limitations for use inside of a bowl. I have been experimenting with the 40/40 for some time and *may* adopt it for use on the outside of bowls exclusively.
    With artritis in my hands, my free hand sharpening days are over, but with jigs, I can get consistant results every time.
     
  9. robo hippy

    robo hippy

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    I have been using the 40/40 grind for a number of years now. I have never used the varigrind set up. If you try to use it for the 40/40 grind, the nose is at 40 degrees, but the wings are more acute, like 35 degrees or so, don't really know. I have no idea how much difference that it makes in using the tool. When I use the 40/40 grind, I mostly hold the tool level, and so that the nose is at a high shear/slicing cut angle, and the wing almost is at a scraping angle. If I was holding the tool with the handle dropped, then I am cutting more with the wing at a high shear/slicing angle. You can do that on the outside of a bowl, but it is almost impossible to do it on the inside of a bowl. Maybe I need to get my varigrind set up....

    robo hippy
     
  10. Mike Adams

    Mike Adams

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    Ron's setup for 40/40 with a Varigrind uses a 3 inch protrusion.
     
  11. Vic Sinai

    Vic Sinai

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    Thank you, I've ordered one and will try it.
     
  12. Karl Loeblein

    Karl Loeblein

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    Vic, did you have any luck with Ron Brown’s 40/40 jig with the varigrind?
     
  13. JeffSmith

    JeffSmith

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    I’ve been using the jig for a while now and find it gives a repeatable 40/40 grind for me. The 3” stickout was a problem on some older (shorter) gouges, but a small wedge helps. I decided to try a couple of the Turner’s Edge gouges that Robust is selling - the flat ground on the top, above the flute the whole length of the tool takes care of this problem. I’ll be adding another varigrind so I’m always setup for both my previous grind and the 40/40. The big differences between the two grinds (other than the stickout) is the leg angle of the varigrind and the distance from the pocket to the wheel. I use a stick for the distance. Shifting from one grind to another is actually pretty quick and easy with a few more jigs to keep track of...

    I suppose its my technique, or lack of it, but I find the grind does a great job on the outside of my pieces with tearout pretty much eliminated, but inside on all but the most open forms my former grind - closer to an Ellsworth profile with longer wings - does a better job overall. I do a fair amount of very open forms where the transition area is practically nonexistent and still prefer my old grind inside. Not a big fan of switching back and forth though I may adapt...
     
  14. John Hicks

    John Hicks

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    I have no problem grinding the 40/40, and anything else on a sorby proedge. The tormek is a problem though.
     
  15. Tom Gall

    Tom Gall

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    I bought a second Vari-grind jig many years ago....mostly because I'm lazy! :rolleyes: One is set for bowl gouges and the other for spindle gouges. The wing nuts are tightened down so much that if I ever wanted to change the angle I'd have to get out the vise-grips - which would make me think twice about that. The pocket to the wheel distance is the same for both jigs so the arm rarely gets moved. "Lazy" has it's advantages. :)
     
  16. Steven Forrest

    Steven Forrest

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    Tom, Would you mind laying out what your settings are for the different gouges? Or show us? Thanks.
     
  17. Tom Gall

    Tom Gall

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    Sure, just took a few measurements - keep in mind that any variations are slight and you will get used to them in short order. My original Vari-grind is so old it doesn't have the notches for setting angles. So these are approximations.

    Bowl gouge: front face to bottom of arm is approx. 48º. Top of arm is approx. at the 2nd notch from the bottom of jig.
    Spindle gouge: front face to bottom of arm is approx. 20º. Top of arm is approx. at the 2nd notch from the top of jig.
    Arm setting: 10¼" from back of the pocket to front edge of clamping jig (Wolverine).
    Tool projection: 1-3/4"
    8" CBN wheel: (I went from a worn down 7" grinding wheel to the CBN and I don't recall making any adjustments)

    Again, everything is relative and you will get used to any minor variables. Hope this helps.
     
  18. Bill Boehme

    Bill Boehme Administrator Staff Member

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    Hard work pays off in the long run, but laziness pays off right now. :D
     
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  19. robo hippy

    robo hippy

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    "Efficiency is intelligent laziness."

    Not sure which that makes me.... No clue who said that, but Henry Ford comes to mind.

    robo hippy
     
  20. Steven Forrest

    Steven Forrest

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    Thanks, Tom. I'll give them a try and see how they compare to what I've got going currently.
     
  21. Emiliano Achaval

    Emiliano Achaval Administrator Staff Member

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    A few weeks ago, someone posted on Facebook a picture of their bowl gouge with what they thought was a 40/40 grind. After all, you buy the jig, so like magic, the 40/40 should appear, right? It was nothing even close to a 40/40. He was proudly showing the Ron Brown jig. I pointed this out to him, then emailed him some pictures. Point is, you have to know what you are after, by hand or with a jig. With practice, you can sharpen by hand faster than what it takes to put the gouge in the jig.
     
  22. robo hippy

    robo hippy

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    Some people just can't learn to sharpen by hand. The skills you need for doing it are the same skills you use when you turn. A, B, C... Anchor the tool on the tool rest, rub the bevel and cut. Took me longer to figure out that I was already doing that part than it did for me to figure out how to do the platform sharpening...

    I haven't tried the Ron Brown jig to see if it works. I am guessing the 3 inch protrusion would change things a lot from the 2 inch protrusion. This makes me wonder if the varigrind jig would do the same thing if you used a 3 inch protrusion on it.

    robo hippy
     
  23. Karl Loeblein

    Karl Loeblein

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    Emiliano, Can you explain how to measure the wings (I.e. 40 degrees) when a gouge’s sides are curved? Seems I might need to get/make an angle gauge like the ones made with several angle notches along the edge. Do you the 40/40 on both the inside and outside of your bowls?
     
  24. john lucas

    john lucas AAW Forum Expert

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    The little round angle guides don't work to measure the wing sharpeness angles. I have one. They simply won't go in far enough to actually get to the angle. Hard to explain but trust me it doesn't work. I thought about making my own with just a small notch in the edge of a piece of stock but I guess I was just to lazy to follow up on that. Mostly because my gouge seems to work perfectly for me. It's a Henry Taylor U and probably does not match the Stewart Batty gouge.
     
  25. Dennis J Gooding

    Dennis J Gooding

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    I agree, and would add that whether done with a jig or freehand, there is no thing as
    A 40/40 grind. Rather, there is an infinity of them, each determined by how much pressure and for how long you grind at each point in the sweep. To define a particular one you need a description or picture of the profile. I suspect that many turners extol the 40/40 grind while using quite different variations of it.
     
  26. Emiliano Achaval

    Emiliano Achaval Administrator Staff Member

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    I do use the 40-40 for the outside and inside, but I I have to use a bottom bowl gouge too, a trade off, you need 2 tools to do a bowl. I prefer that, I have cut my sanding in half. I had Stuart Batty for a week in my house, everyday in the shop. I had no choice but to learn how to do the grind. It wasn’t easy. I can see why people want a jig.
     
  27. Lars Hansen

    Lars Hansen

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  28. robo hippy

    robo hippy

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    Well, as near as I can tell, the only real difference in the different 40/40 grinds is if you have a V flute shape or a parabolic flute shape. With the V, you have the more rounded nose, and the wing is fairly straight. With the parabolic flute, you still have the rounded nose, but the wing has a slight arc to it. Of course, there are many micro differences depending on your sharpening, and some times just on which day of the week it is.....

    As for the gouges I use on bowls, I use the 40/40 for all of the outside of the bowl, and a 40/40 for down the inside wall to the transition. At the transition, I switch to one of many of the BOB (bottom of bowl) gouges I have. Most are 70 degree bevels and have a ) shape nose profile. I have noticed with the 40/40, I have the gouge with the flutes rolled over on the side rather than vertical. This does favor a more rounded nose shape. What this does is give a high shear/slicing cut angle on the nose. The nose does the finish cut, and the wing does the bulk removal. I don't use the swept back gouges at all any more. Only reason for me to use one would be to use the wings for shear scraping, and I prefer a scraper with a burnished burr for that cut. I did wear out 2 of the Ellsworth signature gouges, and then I discovered the 40/40. I think the ideal finish cut with a swept back grind is on the outside of the bowl where you can drop the handle and do a high angle shear/slicing cut with the wing. You can't do that on the inside of a bowl.

    Oh, does any one know, or has any one tried to use the varigrind with a 3 inch protrusion to see if that comes closer to the freehand 40/40 grind?

    robo hippy
     

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