Smooth Curves

[Richard Madison]

Achieving a continuous, smoothly varying curvature can be remarkably difficult for some of us. Well, maybe just for me and one or two others. Have found that simply holding a sheet of paper or something similar behind the workpiece helps me see the curvature better and make it smoother. Also holding one of several french curves (drafting templates) next to the piece helps show where the change in curvature is not as smooth as it might be.

Pieces shown (box elder and mesquite) are good practice and do not require much material.

[robert hainstock]

I wonder if some of us can ever develope a good eye for a curve. Thank you for the tutorial and the weed pots. I will try to remember to post pix of some of mine tomorrow for further scrutiny. The few that I have made have minor differences from yous,but the same basic shape. :)
Bob

[Richard Madison]

Bob,
It is tough when one has simple mechanical skills but very limited artistic ability. But is actually possible to improve by trying harder. Practice makes "better", if you try hard while you practice. Or something like that.

[David Newson]

Richard - As already discussed you are not alone in getting flowing curves right, and I also do a rough sketch on paper and I mean rough I cant draw to save my life and I find this helps, but at other times have found just turn to the shape that's in my head and then I'm pleasantly surprised to find its come out perfect without seemingly trying.

David
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Nothing Ventured Nothing Gained

[Richard Madison]

David,
If you can sometimes just turn the shape in your mind and it comes out right, you may have more artistic ability than you think. It does actually improve with practice. I know some REAL artists who have told me to just keep on working at it.

[robert hainstock]

I use the whats in my head method too. I do not feel that I am artsy talented, but instead yust love shapes, especially round wooden ones.
Here are sime examples.
87181

87182

87183

87184
three are oiled walnut Appx 4x6in. high the fourth is white oak poly finished. Tools used roughing gauge and spindle gauge. I use the gauge as a guide for the reverse curve radius. FWIW!:)
Bob

[Jim Becker]

Richard, you bring up an important point. A number of years ago, I spend an afternoon with past AAW President and outstanding turner Phil Brennion in his Arizona shop. We worked on a simple southwestern style hollowform. He had me turn it to spec and then the critique...and impressionable learning experience...began. It was TOTALLY amazing about how some very, very, VERY subtle changes and adjustments greatly affected the form. The first cut was a very nice piece. By the time Phil was done coaching me, the piece was transformed to something akin to "amazing". And yes, we used the card behind the piece trick to take away any background clutter that would interfere with actually seeing the curves. I highly recommend that everyone take the time to practice the "little things" when it comes to form, curves and transitions between curves. It can really make a major difference in the wow factor.

[Richard Madison]

Jim,
I concur 100%. Glad you mentioned the effect of very subtle changes. Another exercise would be to try to copy Osolnik's classic hourglass shapes. My "copies" are ok, but his are a whole world better.

Bob,
You did not ask, so forgive me, but look at the "kink" where neck meets the top flare in first picture. My box elder has a bit of "kink" there too. The others are lovely smooth.

[Malcolm Tibbetts]

It's been so long, I don't know you to give credit to for this tip. If you hold a pliable rope or chain between your hands, it's almost impossible to create an ugly curve, no matter how you position your hands. The trick is to blend one gravity-produce curve with another. At least, that’s one way that I like to good at curves. The St Louis arch is a great example of a gravity-produced curve.

[Ed Thomas]

There are a few interactive examples of Bezier curves online. Do a web search for 'bezier curve" and you can find them. Some allow multiple control points, but start with something simple like this one Bezier Curve Demo (http://www.math.ucla.edu/~baker/java/hoefer/Bezier.htm).

[Richard Madison]

For those who do not know, the shape that Malcolm mentions is called a catenary curve.

O.T. Was working in downtown St. L. the summer that the arch was approaching completion, so got a charge out of seeing the daily progress.