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I inadvertently did not get my 3/8 inch bowl gouge the full amount (2”) into my wooden block before grinding. Now, I am getting “ears or points” on the back sides of the sweep back sides.
My nose bevel is at 50 degrees.
Previous to my error I had been successful at using the Varigrind.
I am using a slow speed 8 inch stone wheel.
How do I correct the sweep back on the wings?
Thanks
Len Roberts
What do you mean by ears? A common sharpening problem with the V flute gouges like D Way and Thompson is getting a bird's beak as others have called it. This is right by the nose. With a parabolic flute, this is generally not so much of a problem. Because of the straight sides of the flute, if you don't flip a bit more quickly over to the wing, the wheel can tame off too much metal just past the nose. I do talk about that in my sharpening video. Same principal no matter if you are using a platform like I do or if you are using the jigs.
robo hippy
Len -- The fix is simple -- harder to describe than it is to do. You're going to lose some steel, but not a lot. Here's the fix: Use the grinder/platform to straighten the top edge of the two wings. Try to get the edge at the correct angle from the tip of the gouge to the top of the wing, but don't worry too much about it. Close is good enough. At this point, you're just roughing in the correct shape. Once you've straightened the wings, they'll be VERY dull. Sharpen them by correctly mounting the gouge in the Varigrind jig and sharpening as you usually do. It will take a little longer because you'll need to remove more steel than usual. Don't just work on the wings. To keep the wings the same length as they were before, you'll need to remove steel from the nose of the gouge, too. That's just to keep things in their proper proportion.
I hope that makes sense. As I said, it's more difficult to describe than it is to do.
Either Doug Thompson or Oneway has a video covering exactly what David described -- in case you are a visual learner.
Gary Reed (robo hippy), David Walser, Eugene Dixon,
My thanks to all of you for your answers. That helped greatly. I have ground off the ears (extra metal) on the top side of the fingernail grind. As Gary said I had cut too much behind the nose. David's response is in progress.
The bowl gouge is looking better already. Now, I just need to regrind the dull wing edges.
Eugene, Thank you. I will also check out the videos.
I appreciate your quick woodworking knowledge reply to my question.
Len Roberts
San Antonio
For my 3/8" bowl gouge (1/2" bar) I use jig setting 2, for a 1/2" gouge (5/8" bar) I use jig setting 3.
Attachment 475940
To fix your wings put the gouge flute down on the tool rest and grind a gentle curve (arrow). Use the edge of the rest closest to the wheel and keep the flute in contact with the edge as you push the tool up and down on the grinding wheel to get the sweep/curve. Keep the flute against the rest so the wings are ground evenly.
Attachment 475941
After the gentle curve is shaped, then put the gouge back in the Vari-grind and sharpen. The wings will have flat spots on top where they were reshaped so will require a little more grinding.
Pat Scott, Thank you for the photos and information on correcting the grind.
Len
Len,Quote:
Originally Posted by Len Roberts
I usually grind one side of the gouge to suit me then grind the other to match when looking across from the side, then grind the tip to blend into both sides. Then, with a VERY light touch, go over the entire bevel from one end to the other in both directions. Any problems with grind shape are almost always due to spending too much time or applying too much pressure in one or some spots - I make sure I’m moving the gouge continuously and evenly, again, with a very light touch. If I don’t like the wing or tip shape I just grind more where needed - I realize that’s not much help but as mentioned, it’s easier to do and show than to explain in writing.
The “stickout” and the angle setting of this type of jig (Varigrind, Tormek, etc.) have nothing to do with the odd shape you got but do result in different bevel shape when ground, I guess I’d describe, “evenly”. With any of the settings the tip and wings can still be changed (or messed up!) with grinding technique. For example, with any of the parameters you can greatly extend the wings for things like shear scraping simply by spending more time grinding in those areas. The best reference I’ve seen of how the two basic parameters affect the shape is in the Tormek gouge jig manual. I keep an illustration on my computer I usually post but I’m not home right now. However, if interested you can find chart online in the manual for the Tormek jig.
One other thing - some types of flutes (V, parabolic, etc) can need different grinding techniques. Some people, for example, have more trouble getting a perfect grind on so-called V-shaped flutes. I think mostly it’s a matter of paying close attention and stopping a lot to inspect the bevel shape while grinding.
The technique of first flattening the edge to get the desired shape (when viewed from the side) then grinding to a sharp edge can in fact help, especially if a gouge has gotten terribly out of shape, but I find that with practice and care any grind can be corrected without resorting to that. Practice helps but ack, that grinds away the tool! I keep a box of old cheap and free tools so students and people who come for grinding instruction can practice without shortening their expensive gouge or skew! Old tools like this are great for trying out grind variations too.
JKJ
One of the things I've learned is that while these are jigs, they aren't automatic sharpening machines. You need to watch closely what is going on while you grind and take off more or less as you watch the shape of the edge develop. This may mean rolling the tool a little farther or working some areas more or less. The final shape is much more dependent on the operator than we might like to believe starting off with one of these tools. A good strong light and a set of magnifiers can make quite a difference to your sharpening.