I’ve heard it told both ways but I am in the V arm determines the wing angle and the fixture leg determines the nose angle camp.
Wing angle to me is the angle of the cutting edge of the wing, not the angle of the wing as viewed from the side (profile). Given that the protrusion remains the same, and if we can agree that one adjustment affects the other, then my demonstration and explanation on the Ellsworth, Irish, swept back etc. bowl gouge goes something like this.
Grinder is off, this is just a visual demonstration. With a gouge (in this case a bowl gouge) in the fixture with the protrusion you normally use and the fixture leg clamped about midway (forth notch from the top give or take) set the fixture leg in the V pocket with the gouge nose touching the wheel and the handle in line with the wheel, now, move the V pocket in and the nose moves up the wheel making the nose angle more acute, move the V pocket out, the nose moves down the wheel and the nose angle becomes less acute. Move the V pocket back in so the gouge nose is above the center of the wheel, lock the V pocket, loosen the fixture leg and with the fixture leg still in the V pocket nose to grinder, handle away, pivot the gouge nose up the wheel, the nose angle becomes more acute, and, less acute when you pivot the nose down. Ok, so both of those two adjustments positively affect the nose angle.
Now, with the gouge still clamped in the fixture, leg clamped about midway and in the V pocket, roll the gouge onto its left wing. Move the V pocket so that the original wing bevel is in full contact with the grinding wheel. From this position, loosen the wing nut on the fixture leg, pivot the nose up or down the wheel and observe (from the side) that even though the wing bevel changes, it does not change vary much. As the wing moves up the wheel, the cutting edge moves slightly away from the wheel, as the wing moves down the wheel, the heel moves away. Clamp the fixture leg so the bevel is back on the wheel. Now, move the V pocket in or out, the wing angle changes a lot. As the V pocket moves in the gouge moves up the wheel, the wing angle becomes more acute, or, in other words the wing stands up straighter in relation to the gouge. If the V pocket is moved out, the gouge moves down the wheel and the wing angle becomes less acute, meaning the wing rolls in, or over, in relation to the gouge. So, all things considered, while moving the V arm does change both angles, moving the fixture leg changes only one of the angles significantly more (the nose) then the other (the wing).
This is how I set up to grind a bowl gouge on someone else's grinder. I set the nose angle with the fixture leg, and the wing angle with the V pocket. The shape or profile of the wing is determined by me. It can be, short, long, straight, or slightly crowned depending on how far over the fixture is rolled and how long I dwell on any one part of the wing. Once the nose angle is set (approximately) with the fixture leg, the gouge is rolled over to the wing and the wing angle is set by moving the V pocket in or out depending how rolled over or straight up I want the wings. Now the nose angle will have to be readjusted, again with the fixture leg, but not as much as before. Now the wing is off a bit, the gouge is swung back on the wing and readjusted, again with the V pocket. Now back to the nose, readjust. Back to the wing, readjust. Once, twice, three times? Whatever it takes.
A very acute wing angle means the wings are thin and more vertical, for me that would be a catchy gouge. Wings that are less acute means they are more rolled over and are less catchy (for me). To view this, hold the gouge in front of you with the nose pointing up, looking straight into the flute. Looking at the tip of the nose you cannot see the bevel, it is underneath the nose. On either side of the nose, if you cannot see bevel, the wings are very acute and more straight up (V arm closer to wheel). If you see lots of bevel, the wings are rolled in (V arm farther from wheel). How straight up, or how rolled over is personal preference and a tradeoff.
Another variable is the profile, Straight? Curved? Or next, how far back to grind the wing? Half inch? An inch?? Inch and a half???
As Odie states, it’s the results that count. This is what works for me and may or may not fit someone else's understanding, however, I’m always learning and open to suggestions or clarifications…
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