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Grade My Grinds

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Nov 27, 2020
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No holds barred. What would you change? What do you like?
 

odie

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You want your wings to have a gradual convex curvature, like the one in the foreground. The one in the rear looks to have a straight, or concave curvature. You could probably fix that one by taking a little more off the nose, then feathering it out to the wings. The convex curvature is so much more controllable......you'll see that rather quickly! :D
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You might be grinding a little too long at a time, as it looks like you have some bluing there. Keep a water supply handy. Although most turners do not, I do some honing by hand. The ragged looking edges I'm seeing looks like you could benefit from some honing. Although, I no longer use any of the more popular grinds these days, I did use a vari-grind for about 15+ years. I have returned to a traditional grind almost exclusively.....using the v-arm. Even so, I have the same issues as everyone else. Looks like you are using the vari-grind jig, or something similar.

-----odie-----
 
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Yeah, I haven't honed. I think a good bit of the raggedness you see is the burr. Sometimes I sand it off if prepping for a finish cut, but I've seen that if I leave it, it gets knocked off pretty quick during roughing. Thanks for the tips! If I were to admit to having a problem, it'd be the fact that I have been unable to get a tearout-free cut when working with some 3 yr dried Norfolk Island Pine. I seem to get a pretty clean cut when working with green Pecan wood. I haven't really been able to let my tools rip as I am still on a harbor freight lathe, but the jet 1640 is in the mail!
 
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Looks like the smaller is a V flute with long wing ~60 deg Ellsworth, and larger is a parabolic with ~40/40 grind.

2 things on the smaller - as Odie said, flat wings, and maybe a touch of concavity on 1 wing. Nothing wrong with flat, but you want no concavity at all. I find having at least some convex shape is easier to prevent going concave, and I find it a bit more useful for shear scraping an pull cuts. The nose is very pointy I think due to the V flute. Letting the sides of the nose rise a bit could broaden the nose some but, pointy noses are a fact of V flutes.

If the larger gouge is intended to be a 40/40, according to S Batty the wings should be flat and the included angle of bevel and wings 80 +\- a couple degrees. The wings are slightly convex and a bit flat and long. If not intended as a 40/40 but just a lesser bevel angle with wings it looks good to me. Make the smaller gouge wings look more like the larger wings.
 
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Right on! Neither are exact, but you certainly nailed the idea of each. Before I flatten out the wings on the biggun' I'm gonna try and rough out a bowl and see how she runs. I did do a little finish work on a norfolk Island Pine and the first thing I did was bust a big chunk off one of the decorative radial knots. I just got the big gouge yesterday and haven't had a chance to experiment. The little one is ground to a nub (maybe a little too much experimenting), but it certainly paid for itself several times over.
 

hockenbery

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I have seen worse a whole lot when doing workshops

Both tools are usable but the top tool can’t do some cuts.
The top tool will do push cuts well.
Not going to work for shear scraping. Not work well for scraping.
Pull cut would be problematic

what I often see students do is stop on the end of the wing when sharpening - leaving the tool against the wheel instead of picking it up. Leaving the tool in one position on the wheel grinds a flat face which means a dip on the cutting edge.

The way I fix a tool like the top one is to grind from red arrow to red arrow several times and not grind the dip.
This brings the properly ground part even with or a little lower than the dip
Then grinding the whole edge eliminates the dip.
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The biggest differences I see in gouge grinds, is that some like a slight arc/curve to the wing, and some like it to be more straight. Both work. The one that has a slight dip in the wing is not a problem, use till dull and next time you take it to the grinder, more time on the nose and/or more time on the high side of the wing, and/or change your roll rate. With a parabolic flute, you keep a pretty even roll rate. With a V shaped flute and straight wings, you flip over quickly from nose to wing.

robo hippy
 
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Lord no. I started with freehand on a grinder. They cut, but lacked consistency. I basically had to change technique with every sharpening. I then went with a belt sander which was better, but still inconsistent. Then I got the varigrind and built a little make-shift wolverine for it to fit into. It's much more repeatable. I don't have the adjustability of the extendable v-arm, but I've been able to make up for that (for the most part) by adjusting protrusion from varigrind.
 
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