New Steel

[AlanZ]

Please correct me if I am wrong.

I don't know what a "two point fulcrum" could be.

As I recall, a fulcrum is a point that a lever pivots upon. A single point.

You can change the pivot point, but you can't pivot on more than one point at a time.

So, having two available pivot points is different than a 'two point fulcrum'.

Am I missing something fundamental here, or is the word fulcrum just being used incorrectly?

 

[robo hippy]

The bevel does not have to rub to get a cut. This is erroneously called (in my opinion) a shear scrape. It can be done with scrapers, and gouges where the cutting edge is at a 45 or higher degree angle to the wood. This is a clean up cut, and not for heavy stock removal.

I remember seeing Christian Burchard who has a gouge he uses that has no bevel. Never tried one myself.

Off to the symposium today.

robo hippy

 

[MichaelMouse]

Alan, I take OD's "dual fulcrum" as an attempt to describe the technique of rocking the tool back, raising the nose and contacting the heel for a new pivot or swivel point.

OD, I guide on the bevel all the time, it's just that I don't guide on a two-point or single-line basis. I guide, as I keep repeating, along the edge, not perpendicular to it. Keeps the gouge from rolling and catching, as cylindricals are prone. The only time I am without such contact is when I make the initial entry cut, such as here in a plunge and roll. http://s108.photobucket.com/albums/n28/MichaelMouse/?action=view&current=HollowTwo001.mp4

Or here with a poke and peel. http://s108.photobucket.com/albums/n28/MichaelMouse/?action=view&current=CherryPeelIn.mp4

Note how the initial shavings are broad, while as the rate of curve increases near the bottom, the tool is held at a high angle, producing thin excelsior. The tool has a bevel almost twice as long as its thickness, which allows use at a low angle when the walls are more vertical. Versatile gouge, simplest of grinds. Heel never touches. Hippy will recognize it as a "shear scrape" with a small sharpness angle grind.

Can't claim to be the originator, it's the way everyone cut before gouges became cylindrical.

 

[odie]

Please correct me if I am wrong.

I don't know what a "two point fulcrum" could be.

As I recall, a fulcrum is a point that a lever pivots upon. A single point.

You can change the pivot point, but you can't pivot on more than one point at a time.

So, having two available pivot points is different than a 'two point fulcrum'.

Am I missing something fundamental here, or is the word fulcrum just being used incorrectly?

You are right, AlanZ.......

Perhaps that's not the best description of what's taking place. It's a single point of fulcrum, but describing two points of contact with the wood......heel of the grind bevel, and the cutting edge.

ooc

 

[hockenbery]

convex grind - Johanes Michealson

Johanes uses a convex grind on his bowl gouges.
Turning hats (Johanees is the master) requires thin walls and a couple of tight radius curves.

The convex bevel is the best solution I know of for turning thin and tight radius hollowing. The convex grind has minimal bevel drag as there is only a micro bevel contacting the wood behind the cut. with no heel and a short bevel the tool will turn a very tight radius needed for the crown of the hat and the top of the brim.

Bevel drag sets up vibration in the tool and the wood. to experience extreme bevel drag, when turning a bowl push the bevel hard against the outside of the bowl. The tool will bounce uncontrollably and you will be unable to cut using that much bevel pressure. When turning thin bevel drag becomes an issue even with light bevel pressure. Shortening the bevel by switching to a smaller gouge, or grinding a secondary bevel reduces bevel drag. The convex bevel already has the micro bevel.

for turning tight radius inside curves grinding the heel from the bevel shortens the bevel and a allows a tighter radius. The convex bevel has no heel and allows tighter radius to be turned.

I use a Michealson grind on my finishing gouge for tight turns on necks of some hollow forma and fro hollowing spheres. It is a great finishing grind and great fro tight radius inside cuts.

if you own more than 4 gouges try putting the Michelson grind on one.
Jonannes has a video on grinding ad a few others on http://www.woodturningvideos.info/tag/michelsen/

happy turning,
Al

 

[Mark Wollschlager]

I have one old glaser black handle 5/8 gouge that I got from JoHannes.
He put his grind on it and it works great.
This is jinxing things , but it doesn't catch ( as much ) while getting those curves and working with the finish cuts on thin bowls.
Resharpening has always been an issue for me. keeps me from using it as much.
I need to watch those videos a few times.

mark