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Problem with bowl gouge angle

Joined
Feb 25, 2020
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Mesa, AZ
I have always sharpened bowl gouges at 40°, but I recently bought a new 1/2" bowl gouge and I reconfigured it to a 40° side grind and am having problems. As you might be able to tell from the attached photo, sharpening it to that angle is causing a 'squared-off' point, rather than a curve. This new gouge seems to have a much deeper 'V' that my previous gouge of the same size, and I think that is the cause. So, I'm wondering how to change the angle to create a more rounded sweep. I hate to start experimenting and unnecessarily grind off a bunch of metal. I have always liked 40° for the 'Anchor - Bevel' part of the process, especially on the inside of the bowl. What angle do you suggest?IMG_1089.JPEG
 
Joined
Aug 29, 2019
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Vienna, ME
Hi Dave,
My responses are always IMHO - because I ain't fit to say anything stronger. I attended a Stuart Batty turning school a couple of years back and we spent a fair amount of time grinding 40/40 gouges. The pointers that he gave me turns out to be my key to getting a good shape in addition to the 40 degree bevel. In words (hard to do) this is what I remember of what he said:
  • Start by marking a 40 degree angle to each side of your grinding platform, meaning 40 off the perpendicular center line of your wheel.
  • Set the gouge on the grinding platform with the flute closed (open?) to the right and align the axis of the gouge with the 40 degree line on the right side of the platform
  • Keep the flute closed to the right as you move the handle of the gouge from 40 degrees down most of the way to maybe 10 degrees - don't start rotating the gouge until you get down there. (This is what I screw up most often and I wind up with a pointed gouge instead of a rounded nose).
  • Once you reach about 10 degrees off the perpendicular center line of the stone, roll the gouge open upward as you come down the last 10 degrees. So sweep the handle to bring the gouge to 0 degrees and roll the gouge from closed to the right to open upward.
  • Bring the grind a little past center but don't try to continue the grind very far to the left.
  • Now align the gouge on the left hand 40 degree line of the grinding platform, flute clolsed to the left and repeat the operation.
  • Your two grinding passes should overlap a bit in the center of the grind.
Stuart often makes a pass or two with the flute open upward from 10 or 15 right to the same amount left to blend the final grind.

I have the most trouble when I get to near the perpendicular center line - I have to be quite careful and use a light touch to avoid burning the edge. Not that being ham fisted works well for me anywhere during the grinding process!

But I'll bet you get a bunch more comments and maybe there's some YouTube content on grinding the 40/40 gouge. Anyway, consider the source!

Regards,
Tom
 
Joined
Feb 26, 2019
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Need more info:
> what grind are you trying to achieve - try to find a pic that shows it
> by hand on a platform or using a jig? Which jig?

General comments on bg sharpening:
> form is achieved through removing material
> if material exists where it shouldnt (the wings) spend more time there removing material
 

Roger Wiegand

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Looks to me like you don't have a 40 deg top bevel, and also have a lot of curve to the wing. Easiest way to fix that is to set a platform at 40 deg to the wheel then flip the gouge upside down (flute to the platform) and grind until there is a flat around the entire surface of the flute. Then you can flip back to flute up and with the platform at 40 deg and the gouge angled at 40 deg grind each side of the flute until the flat you formed just disappears. This will require a bit of rotation as you get away from the tip. You want those sides pretty much straight. Then swing the gouge to finish the nose, again only removing enough to eliminate the flat.

It's important to watch carefully (magnifiers and a strong light help me), taking away metal only where there's too much and avoiding the dips that can form at each side of the tip. Focus on making a nice smooth curve.

I do the above procedure only when I've messed up the grind through inattention or gotten a chip in the edge, not every time I sharpen. Remember it's perfectly reasonable to dedicate a centimeter or two of the gouge when you're perfecting a new grind to "sharpening tuition".
 
Joined
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Eugene, OR
Brian's 40/40 grind looks good. I can't really tell from your one picture of your gouge what the problem is. As near as I can tell, it doesn't appear to have the 40 degree sweep to the side.

robo hippy
 

hockenbery

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sharpening it to that angle is causing a 'squared-off' point, rather than a curve

A dip in nose of the gouge is caused by grinding it too much.
There is less steel under the nose than under the wings.

Regardless of the profile no dip or flat on the nose.

One way to correct this is to grind each wing twice avoiding the nose. Then make one grinding pass from wing to wing across the nose.
 
Joined
Feb 25, 2020
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Mesa, AZ
I re-watched the Oneway video for the Vari-Grind 2 that I use and made a few tweaks to reduce the sharp point on the transition of my gouge. I watched several videos on the 40/40 grind and might try that someday. I also found a jig by Ron Brown for obtaining a 40/40 grind using the Vari-Grind. Something to consider also.

I'm going to try the adjusted swept-back grind first, since I am used to that.

Thanks for all the tips.
 
Joined
May 4, 2010
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Bozeman, MT
David,

The Oneway sharpening DVD may be different from what it was 5 years ago or you might be one of the rare individuals who can make sense of it. Otherwise, Run Toto Run.

The Oneway DVD used to be confusing and ineffective. Use the set up for the varigrind jig provided by Doug Thompson on his web site or get the DVD on sharpening from Kirk DeHeer. These are not identical methods, but pick one and follow it, they are understandable and effective. IMHO, you'll be much happier. And have longer, sharper tools.

Eventually, you may want to create a specific grind, such as the Ellsworth/Irish grind or the Batty 40/40 grind or the Michalson grind. But as a place to start, either of these settings/methods for the Varigrind will get you a consistent, workable bowl gouge.
 
Joined
Feb 28, 2021
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Roulette, PA
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www.reallyruralwoodworks.com
Agree with Dean - The oneway wolverine video was ok, but the varigrind video left a great deal to be desired- I had trouble figuring it all out, then I watched Doug Thompson's video (on his thompson tools website, I don't have the link offhand) From that I finally figured out how to create and form the gouge grind I wanted in the first place, and once I had that down pat, I took a little time to think about the various settings (Thompson had me setting gouge at 1-3/4" protrusion and pick a "wing notch" on the vari-grind and leave it there, for example, while Others say to use a 2 inch protrusion, etc.)

What I figured out was, I was able to set my WOLVERINE arm in ONE SINGLE position and leave it there (I cut a scrap of wood to space it away in case I needed to adjust or move it for something else) , and from that one position , I am able to do my 3/8 spindle detail, 1/2 spindle detail, my 55 degree ellsworth, grind, 45 degree "sorta traditional , almost 40/40" 5/8 roughing gouge grind, and my "almost 40/40" bowl gouge grind without ever moving the wolverine arm - all I do is change the "wing notch" position to get the wing I want, and adjust the protrusion depth of the gouge (from the vari-grind) using 3 scrap pieces of 2x4 - setting them to either 1-3/4", 2" or 2-1/4" gives me the different angles of grind, while the wing notches control the amount of sweep/roll of the nose - much easier set up, and it works great for me.
 
Joined
Feb 26, 2019
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There is a significant difference between the Varigrind and Varigrind 2. The same setup will not result in exactly the same grind result. The 2 does not swing the tool shaft to the side as much, due to the pivoting of the arm vs the Varigrind swinging the entire jig.
 
Joined
Feb 12, 2018
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Millington, TN
There is a significant difference between the Varigrind and Varigrind 2. The same setup will not result in exactly the same grind result. The 2 does not swing the tool shaft to the side as much, due to the pivoting of the arm vs the Varigrind swinging the entire jig.
Doug, The Varigrind2 pivoting arm can be used without it’s base. Just stick the pivot arm into the same base that’s used with skews or Varigrind1. The pivot point is slightly different between both pivot arms, but I can duplicate most Varigrind1 grinds by adjusting the Varigrind2 settings.
 
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