gouge bevel issue

[Robert Feingold]

Some of my gouges have a v notch in the center of the edge after i sharpen them see photo with arrows. (sorry the photos are not very clear.) The flute also has a v shape. Is this common? Is there a way to avoid this? Will this cause a catch?
This does not happen with my other gouges that have a more rounded flute.
I'm using a vari grind jig.
Thanks,
Rob

 

[n7bsn]

Rob, the issue is how you are using the jig. It might be the jig is setup wrong, it might be the amount of time you are spending on the tip, I will guess and say the issue is probably both.

My best recommendation is to find someone in your area that can show you exactly how to use the system.

Myself, I would not use the gouges the way you have them

TTFN
Ralph

 

[robo hippy]

Okay, let's see, mostly it is the 'art' of blending the wings into the point. Process is either round the nose first, then blend the wings into the nose, or do the wings and then blend the nose into the wings. Mine always end up lopsided, but they still cut. Not really a problem. If the nose is kind of snaggle toothed, then it doesn't really cut well. So, you most likely are not blending enough as in spending more time on the wings, and not enough on the nose. I free hand sharpen, and have experienced the same problem. The V/parabolic curve flutes seem to work a little better for the 40/40 (bevel/sweep) grind than the more open fluted designs. Not sure if this helps or not.

robo hippy

 

[Grant Wilkinson]

I'm something of a newbie, so YMMV, but I think that Robo has hit it. I was getting the same profile and knew it was not what I wanted. I was not spending enough time on the tip of the gouge. I was spending most of my time on the wings and ending up with a pointed end on the gouge. As soon as I started concentrating on the tip, that problem went away. The gouge was very catchy when it was pointed.

 

[john lucas]

Watch my video on sharpening problems. It will probably answer your question. Your just staying too long in the dip area when you sharpen. Try being extremely light or even passing over that area until you get the edge back to where it should be.
http://www.youtube.com/watch?v=M9G16ylEZHQ

 

[Dennis J Gooding]

Robert, it is hard to tell for sure looking at the pictures, but I would guess that you are not using a vari-grind jig or equivalent for sharpening. It looks like you are rolling the gouge laid flat on a tilted table rest or have the end of the handle in the Vee pocked of a Wolverine fixture. Whatever the case, the rule is the same, just keep grinding away at whatever is sticking out too far. However, note that you will never produce a useful long fingernail grind with the rolling approach or the pocket approach. On the other hand, some prefer a stubby fingernail or no fingernail on their gouges.

Dennis

 

[john lucas]

Also if your camera won't focus properly move further away or shift the camera around until it will. Usually the focus point is somewhere near the middle and if you move the gouge tips so they are in the middle of the frame it might help.
Many cameras also have focus lock, which is usually pushing the shutter button down part way. Move the camera around until you get the proper focus point, hold the shutter button down and reframe and then shoot the picture.
Most cameras now days you can actually see the image on the back of the camera. Keep shooting until you get a good one instead of sending out of focus photos for us to try and evaluate.
I'm not picking on you per se. We are always glad to help with your problems. I see these out of focus photo an awful lot and I'm just trying to help. People send out horribly out of focus photos of a log and then want us to identify it. Well Duh, it's impossible. In your instance the photos were close enough we could see the problem but it sure would be easier if they are sharp.

 

[Richard Coers]

For sharpening with the vary-grind, I tell new folks to treat the sharpening of the gouge as 3 zones. One wing, second wing, then point. Spend just as much time on each zone, blending the wings to the point at the final motion. You can get a catch anywhere, if you come off the bevel. Just having the v that you describe will not guarantee a catch.

 

[hockenbery]

Lots of good advice.

There is less metal on the tip and more so on the vee shaped gouge.

I tell my students to sharpen each wing from the back edge to close to the tip and back to the back edge.
Keep the tool moving.
This sharpens each wing twice.
Then make one pass across the whole edge from back edge to back edge.
This sharpens the tip once and blends the wings into the tip.

For most folks this works extremely well.

Any gouge needs a continuous convex edge to work well. If you have a concavity on the tip it is likely to make a catch when you roll the tool.

Have fun!
Al

 

[Mark Levitski]

The vari-grind jig does not automatically make sharpening "idiot-proof" (no reflection on the OP or respondents). There is some things to learn for it to work well, as others have pointed out.

"Any gouge needs a continuous convex edge to work well. If you have a concavity on the tip it is likely to make a catch when you roll the tool."

By design, all surfaces ground on the wheel will be concave. No escaping that. However, I have never had any problems or concerns w/ regard to this in my turning. I know that Al is thinking about bevel contact here, but IMO it is inconsequential especially for novices who might worry about every little thing to explain their catches.

 

[john lucas]

Al is talking about having a concave dip in the cutting edge. That can grab the wood when you go across it and is more likely to cause a catch.

 

[odie]

All good advice, so far.......

(I'm using a Wolverine w/Vari-grind jig, and also do many straight grinds using just the V-arm.....the techniques described in this thread apply to both methods of grinding a bowl gouge.)

The point to remember is there is "blending" of ground edges.......it's not one continuous motion from one wing, around the tip, to the other wing. Any of the methods described will produce the desired result with practice. What you want to end up with is one continuous sweeping curve of the cutting edge (without facets or abrupt changes in the grind) all the way from the furthest point on the wing around the tip, and continuing to the furthest point on the opposite wing.

As Robo Hippy points out, the wings don't need to be exactly the same on both sides. You never use more than one wing and the tip for any cut, so either wing only need to have a smooth transition to the tip to have a good cutting ability.

Added to the above methods described in this thread is starting the grind on the furthermost point on one wing, and sweeping around to past half way around the tip......then do the other wing in the same fashion, blending one side to the other.

I use a combination of all the methods described by all those who contributed to this thread. The determining factor is the looks of the gouge you intend to grind. Depending on how you "size it up", will influence just how you want to go about it.......

A "V" shaped flute, from my experience, is a little more difficult to get a good transition around the tip. For this reason, I don't like them as much as a "U" shaped flute, but I have a few of them......so, I deal with the associated difficulties. I'll be willing to bet this is the source of Robert's difficulties with sharpening, in his original post. You just have to arc the grind around that tiny little tip too fast to have good control over the transition from a gradual curving wing to small radius tip, or vise versa.

From what I can tell, I see no advantage to using a "V" shaped flute, but there are definitely disadvantages to grinding them. For any practical use, I feel that if a smaller tip is wanted, then a smaller gouge with a smaller "U" shaped flute is the better solution. For cutting wood on the wing only.....then the flute shape makes no practical difference.

As usual, NONE of this is to deny that others might have differing methods that work for them.......I'm just explaining what does work for me.

ooc

 

[john lucas]

What I like about the V flute is the wings have a thicker cutting angle. My U shaped gouges have a sharper cutting angle on the wings and I use that to get really clean pull cuts. I think the wings of my V gouge hold an edge longer because they are a thicker angle. It's a subtle thing but I've been playing with it for a while and trying to understand the differences.

 

[Bill Boehme]

John is probably right, but I sort of agree with Odie about not caring for the V shaped flutes. I grind all of them to get the bevel shape that I want which is mostly a short swept back shape about 5/8 to 3/4 inch. I have one half inch bowl gouge with a V flute and 55° nose angle. To me, the bevel on the wings on this type of gouge seems a bit too wide even though I try to minimize the time spent on sharpening the wings.

For the benefit of the newbies, if you grind too much on the wings, the angle will become thinner than it ought to be, at least in my view. I prefer a fatter angle on the wings. If this happens to your gouge, the only cure as far as I know is to grind away a lot of metal on the nose to bring the whole edge back to where it ought to be.

 

[robo hippy]

There is a lot of differences in V gouges. I saw one from Jet where the V was so steep and pointy that it would be best used for playing mumbly peg. I have a Glaser V which I don't really care for, but love the Thompson V gouges, which are more of a U or parabolic curve on the flutes. I do like a slightly more open flute, but I tend to use them rolled high up on the side for a high shear angle.

robo hippy

 

[john lucas]

You guys are correct in that there are different V's. Also different U's if you count things like the superflute which is sort of betweent the two. I also assumed these are sharpened on the Wolverine. If you change the length of the arm on the sharpening jigs it can change how the wings are sharpened by rolling over the outer edge. This can give a U shaped tool a more blunt angle.
I also find that some gouges have more metal on the wings of the U shaped flutes. This is done using a narrower tool to grind the flute. David Ellsworths gouges have this. It makes for a much beefier edge that gives the same benefits of my Thompson V gouges. My old Sorby on the other hand has a very wide U so when I sharpen the wings the angle comes out to be about 25 degrees or even less. I've ground this gouge with very long wings and use it for problem woods where I can use a pull cut with the handle very low so I get an extreme shearing angle with a very sharp edge.

 

[robo hippy]

One disadvantage to the gouge jigs is that when you roll the tool on its side to grind the wing, the amount of roll is set by the jig. When you do it by hand, you can roll over farther so the wings don't get over ground and end up too thin.

robo hippy

 

[john lucas]

Right you are. You can also custom grind many tools using just a tool rest. my rough out gouge has the upper U's ground back very slightly from vertical and they are as straight as I can make them. I use them like mini skews when I'm roughing so I can almost complete the spindle with that one tool.
I have several small tools that simply won't fit in any jig. A tool rest and careful hand sharpening takes care of those.
Of course I grind my scrapers on the tool rest. No reason to have a jig for those.