is all about 30 really good seconds...
"Chattering" the inside. Pulling from the center out, Paulsen cuts a ring of chatter that resembles beaten metal on the inside of a bowl.
I mount the tenon in a lathe chuck. 1 make the tenon about 3/4 in. long and insert about Vl2 in. of it into a Jacobs three-jaw chuck that screws onto the threaded headstock spindle of my lathe. (For more on chucks, see AW #43.) The blank should spin perfectly concentrically at this point.
First I turn the basic form that 1 wrant, then I sand it to 320 grit and oil the piece, running the lathe at around 200 rpm. Sanding can quickly heat up the thin walls of vessels, causing checks.
Increasing the flex. Paulsen reduces the tenon diameter to induce more wobble, prior to "chattering" the outside bottom of a bowl.
When I feel the wood getting hot under my fingers, I cool it down and raise the grain at the same time by rubbing the smooth areas with water from a damp rag. Be careful not to wet any chattered areas. When the wood is dry, I knock off the raised fibers with some fine-grit sandpaper.
My next step is to buff any outside surfaces with the piece off the lathe. (I simply oil the interiors of hollow vessels.) Before taking the work out of the chuck, I make an index mark on the tenon that lines up with a previously made mark on one of the jaws of my chuck. This way, I can line up the marks to keep the piece concentric when 1 chuck it back on the lathe. I polish the piece by spinning it against two linen buffing wheels, the first wheel charged with tripoli and the second with jeweler's rouge. This successive polishing produces a mirror-reflective surface.
Now I'm ready to chatter. Interesting chatterwork doesn't happen with every cut, and there are as many approaches as there are designs. Chatterwork looks best if you give it a "foil," an uncut, polished adjacent area that helps to set off the design.
I start chattering the largest diameters and the areas farthest from the chuck. These arc the areas with the most flex. I start chattering at slow speeds—300 to 500 rpm—working with a skew or my miniature straight tool.
To chatter these areas I often use a trailing cut, where 1 hold the tip of the tool below and to the left of center, pulling it across the surface. (See left photo, above.) I use light pressure with the tool to push the workpiece, causing it to ilex on its thin tenon. Sometimes I press and release the tool repeatedly.
A DIFFERENT APPROACH: CHATTERING WITH A FLEXIBLE CHISEL
by Bonnie Klein
There are two reasons why a turning will "chatter": Either the wood moves or the tool moves. To produce chatterwork (see main article), I use the second method by letting the tool movement create a pattern. The tool I use, called a "Chattertool," was designed by turner Dennis Stewart.
Stewart's chatter tool (available from Dennis Stewart, 52180 NW Scofield Rd., Buxton, OR 97109, (503) 324-1111) has a substantial handle with a piece of spring steel mounted in the business end. The overall length of the tool is about 9 in. The length of the tip is adjustable, and once you've set the length, you press the tip against the spinning workpiece and a chatter pattern occurs as the tip "bounces" against the surface.
You can get different patterns by changing the surface speed of the material, the pressure of the tool, and how fast the tool is moved across the surface. I get the sharpest chatter detail on end grain, but I also use it over the entire surface of materials without true grain, such as tagua nuts, bone, antler, plastics and soft metals.
The tip of the Chattertool seldom needs sharpening, but when it does I regrind _
the edge to the factory-ground 60°, then remove the resulting burr by taking a couple strokes across the top of the tip with 220-grit sandpaper.
The tool works well on large or small work. On 2-in.-dia. work, I generally set the lathe speed between 1,000 and 3,000 rpm. The faster the speed, the larger the chatter pattern. Slower speeds produce finer patterns. As the diameter of the work increases, I increase the pressure of the tool to maintain the chatter rhythm. I find it best to set the tip about 11/8 in. long and to let the shank—not the tip—bear upon the tool rest. If the tip is too long or too short it won't settle easily into a chatter rhythm. Holding the tip at 80° or less to the work offers the best opportunity for chatter to result.
BONNIE KLEIN travels the country turning and teaching; she lives in Washington state.
Vibrating chisel. The tip of this tool ilexes as it presses against the spinning work, creating a pattern of chatterwork.
Burnishing with wood. To highlight the designs> Paulsen rubs the chattered patterns with a stick of wood of the same species as the workpiece.
To vary the chatterwork pattern I might make a shear cut, where the tip presents a low angle to the surface. Here, I push the tool across the surface from above center to cut against the rotation of the piece.
As I'm cutting, 1 listen to the sound of the tool against the work. A rhythmic, percussive sound tells me I'm getting some chatter. The more musical the sound, the finer the chatter will be.
I stop the lathe constantly between cuts, looking for symmetrical patterns, sharp detail, or imperfections (you can't see the chatter-work as it's happening). If I don't like what I see, I'll remove the chatter with light cuts from a skew and try again. For this reason, leave some margin for error in your piece.
To shape and chatter the inside shoulders of hollow forms, I use the miniature hook tool, pulling the tool away from the center and taking very light cuts.
To chatter the inside bottom of a bowl or vessel, I use the skew or the miniature straight tool in a series of trailing cuts. I may cut a few fine beads, then a series of concentric rings. Sometimes I II make a light sweep over a wide area to get a pattern that resembles beaten metal.
Once I get a pleasing ring of chatter, I burnish it before moving on to the next area. Burnishing polishes the high points and accentuates the texture. My burnisher is simply a l/4-in.-square stick made from the same species as the spindle I'm working on. I grind one end of the stick to a point on a belt sander, then I hold the stick against the spinning chatterwork and press lightly. (See photo, left.) A couple of seconds is enough to highlight the area.
As I near the chuck end of the piece, the chattering effect lessens. So I create more flex by increasing the lathe speed to around 1,500 to 3,000 rpm and progressively reducing the diameter of the tenon with a parting tool, taking off about ®/16 in. at a time. Then I chatter the bottom of the piece with the skew or miniature straight chisel by pivoting the tool on the tool rest.
I may turn a couple of rings with the point of the skew to set off the chatterwork design. If the piece starts to vibrate too much, I wrap some masking tape tighdy around the spindle to stiffen it. A
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