Article: David Ellsworth Demonstrates For CMW June 18, 2016
June 28, 2016 16:16, submitted by Tina Collison (author: Bob Gunther, photos by Scot Roberge)
David Ellsworth Demonstrates for CMW June 18, 2016
Learn more about David at: http://www.ellsworthstudios.com/
Also, there are DVDs of David's prior demonstrations available to members in the CMW Library.
David comes to CMW from Quakertown, PA where he has his home and studio. It is also where he conducts the Ellsworth School of Woodturning.
David first used a lathe in a workshop class in 1958. He continued to turn throughout high school. After high school he spent three years in the military and then eight years in college. He studied architecture, drawing, and sculpturing. He received a Master's degree in Fine Arts from the University of Colorado in 1973. He started the woodturning program at the Anderson Ranch Arts Center in Snowmass, Colorado in 1974 and the following year opened his first private woodturning studio in Boulder, Colorado.
David developed, during the mid-1970s, a series of bent turning tools and methods required for making thin-walled hollow forms for which he has worldwide fame. His first article was, "Hollow Turning" in the May/June 1979 issue of Fine Woodturning Magazine. Fox Chapel publishing released his first book "Ellsworth on Woodturning", in 2008.
David is a founding member of the AAW. He was its first president (1986-1991) and its first Honorary Lifetime Member. He has participated in every AAW symposium including this year which celebrated AAW's thirtieth anniversary. He has authored more than 50 articles on subjects related to craft and woodturning and opened the Ellsworth School of Woodturning in Quakertown, PA in 1990.
David's work is featured in the permanent collections of 42 museums. In 2009 he was elected the "Master of the Medium" by the James A Renwick Alliance of the Smithsonian Institute in Washington, DC. He is an Honorary Lifetime Member of the Collectors of Wood Art. David has demonstrated for CMW in 2002, 2008, and 2012. He taught CMW classes in 2012 and is scheduled to teach two CMW classes on June 19 and 20 of this year.
David began his demo turning an open cherry bowl. The blank was a half log mounted between centers. The bark was on the tailstock side. David uses 5 different cuts. He began with the roughing cut where the left side of the bevel is held vertical, or nearly so, and does the cutting. The bark on the tailstock side was removed. Then the slicing cut was used. The tool handle was lowered and slightly rotated. David then drew a line around the piece, delineating the largest possible depth that a bowl could be made from that piece. Then the corners of the piece were removed from the drawn line to the headstock side. This produced a circular blank from the half log piece. All the bark was turned away. At this point the piece can be balanced making subtle changes in grain direction and balancing the heart wood/sap wood positioning. The point of reference for balancing was the bottom of the sap wood. It was achieved by changing the location of the tailstock center. The diameter of the spigot for the chuck was determined. Large jaws were used. To form the tenon a scraping cut was used. The flute was held nearly perpendicular to the lathe's ways. A detail gauge was used to prepare the dove tail shape of the tenon. The heel of the tool had been ground away. Then another cut (base cut) was made to define where the outside shape would proceed into the foot of the piece. The stem remaining in the center was turned small enough to fit into the center of the jaws. This preserved the center mark when the piece would later be placed on the jam chuck.
The piece was removed from between centers and placed in the #4 jaws of a Vicmarc 120 chuck. The tailstock was brought up for safety, support and to prevent vibration. The slicing cut was then used to flatten the tailstock side of the piece. Then the outside was shaped using the slicing cut going from the front to the rear. Then the direction of the cut was changed to go from the rim to the foot. This eliminated pull out from the foot to the rim cut. To finalize the surface, a sheer scrape was used. Here the flute was closed over to a near vertical position to the ways and parallel to the wood surface.
The tailstock was removed to enable hollowing of the piece. The roughing cut was used going from just left of the center to center. This prevents tearing the fibers. At the beginning of each cut the flute needs to approach the wood in a vertical position. The handle his held to the right so that the flute is perpendicular to the entry into the wood. If it is rotated it will scoot on the wood surface. The interior was then finished using the finishing cut. This cut of all 5 requires the use of the bevel to ride the wood surface. You cannot let the left side of the bevel enter the wood or you will get a major catch. When doing the interior finishing cut you need to have your body positioned so that at the completion of the cut at the center of the bottom you are at your most relaxed position.
At this point the interior was completed and 2/3 of the outside. The piece was removed from the jaws and placed on the jam chuck. The jam chuck was made using a Bealle tap to make the one and quarter spindle recess. It was then turned to fit the piece and then padded so as not to mark the piece. The tailstock was brought up to the original center mark. David then drew 3 pencil lines. The first line marked the interior bottom of the piece - the second 3/16 deeper than the first. This delineates the thickness of the foot. Then the 3rd line is 1/16 inch deeper than the 2nd. This is the actual bottom of the foot, thus allowing 1/16 inch for the recess in the base of the foot. A detail gouge was used to detail the foot and to part it off. The final parting cut was done by rotating the lathe by hand.
David then turned his attention to turning a natural edge cherry bowl. A large 4 prong drive center was used in the headstock to grip the bark side of the half log. The tailstock was brought up. David roughed out the piece quickly starting at the tailstock side and advancing to the wing tips. The tenon was formed and the base cut made (the base cut needs to direct the outer bowl surface shape into the interior portion of the wood held in the large jaws) The piece was then removed from between centers and placed in the number 4 jaws on the Vicmarc 120 chuck. The tailstock was brought up. A slicing cut was used to go from the rim to the base. This gives a crisp edge to the bark rim. The tool rest needs to be adjusted before turning on the lathe so that the wing tips do not strike it. David turned left handed when doing the outer edge so he could site along the outside surface of the piece and make sure the wall thickness stayed constant. A sheer scraping cut was used to further refine the outside surface. The tailstock was removed and the interior hollowed as was done earlier with the open bowl. As the hollowing progressed the tool rest was moved into the interior of the piece to give better tool support.
The finishing cut of the natural edge bowl was done by looking down on the top of the piece so you could see between the wing tips as the piece rotated. The depth was eyeballed using the pencil and the piece hollowed to its final depth. The piece was removed from the chuck and placed on the jam chuck. The three lines were drawn as done earlier and the foot completed. This completed the natural edge hollow form and the morning session.
David began the afternoon session turning a side grain hollow form from a section of a log. The log section was placed between centers at the cut ends of the log. He roughed it into a cylinder. The tailstock end was rounded off leaving a tenon. The piece was then reversed between centers and again the tailstock end rounded thus creating a sphere with protrusion at two sides. While spinning a pencil line was scribed in the middle. This line becomes a design line later in the demo. The area of the final opening of the vessel was also marked. The piece was rotated so that the centers were on the pencil line. This placed the protrusions (tenons) perpendicular to the ways. Then the piece was centered with the pencil line equal distance from the edge of the tool rest. Then the tenons were turned away. At this point both pith areas were exposed as to their exact location. The piece was rotated so that both piths were rotated. Having the piths going straight through the piece lets any distortion during the drying process be more uniform and more pleasing to the eye. The tailstock end was flattened and a tenon formed. A base cut was made. The remaining spindle was thinned so that it would fit into the opening of the chuck center. It was then placed in the jaws of the Vicmarc 120 chuck. The tailstock was brought up and the piece shaped so that the apex of the vessel sides are the piths. A pull cut and a scrape cut was used. The opening of the vessel was shaped. A sheer cut was used to produce a final surface. The outside shape was such that it will continue into the wood inside the jaws in the final form.
Hollowing was then begun. It was done in numbered staged depending on the location in the vessel. Some areas were done using the straight tool and some with the bent tool - some with both. (see photo) The opening was achieved with a straight tool from left to center progressing deeper into the vessel. David does not drill out the center because the drilling process heats up the wood. This can cause cracking, especially near the vessel's opening. (Hollowing cutters can be purchased from EmCo - Square 3/16 inch cutters #3835212- for the bent tool and Square ¼ inch cutters #3835216 for the straight tool) After using the straight for a distance the bent tool was used to clean up the lateral areas. Then the process was repeated, working through the numbered areas noted above. Frequent evacuation of shavings and dust needs to be done - best with a compressor and a bent spoon shaped scoop. David wraps the piece with stretch tape during the hollowing process to help keep moisture in the piece and prevent too rapid drying. Wall thickness is measured with a bent loop caliper that is made from a 3/16-inch-thick rod. One side of the loop is straight and the other curved. Having the curved arm outside and the straight arm inside the vessel will permit measuring the wall thickness in the upper parts of the vessel. With the curved arm insides and the straight arm outside you can measure the lower deeper vessel wall thickness.
Once hollowed the piece was removed from the jaws and placed on the jam chuck. The tailstock was brought up. Before tightening the tailstock, the tool rest was placed near the piece and your finger held against it. While slowly rotating the piece you can feel any changes in diameter of the vessel and adjust it so that it will run as true as possible. The tailstock was then tightened. Then the 3 lines could be drawn and the shape of the foot established. The detail gouge was used to complete the base and remove the stump. This completed the hollow form.
David then turned to sharpening and stressed several points. Sharpness is determined by the mass of metal behind the cutting edge. The less the mass the quicker the tool dulls. When using the grinder address the bevel and not the edge of the tool. This will make grinding easier. CBN wheels prolong tool life and are quicker, cleaner, and produce less heat. The newer powder metal tools are more responsive during the turning process. Once a tool needs to be pushed more into the wood, or needs to be used for multiple passes over the same area, it needs sharpening.
This completed an excellent demonstration which was witnessed by what seemed to be a record number of members attending. A video will be available in the Club library in the near future.
Submitted by Bob Gunther