ART OF OVAL TURNING
Some years ago I came across a shop outside of Boston that had a long history of oval picture frame making. As it turned out I spent a good part of a day with the turner examining the lathes, chucks, tools and finished products that were turned in this manner (visit my “Articles” page, “Old Swamb Mill,” on this site to see what I encountered and learned).
I was also aware that the first book written in the western world specifically dealing with turning (The Art of the Turner by Plumier, 1701) showed several chucks that propelled the piece in an elliptical orbit.
Around the time of the article I wrote on the Old Swamb Mill I heard that Johannes Volmer of Germany had designed a modern version of the oval chuck. Working with Vicmarc of Australia together they produced the VOD (Volmer Oval Device). More than a simple chuck, it is an engineering marvel. It overcomes some of the shortcomings of the original chucks in that it has a balancing system, is much more quiet, does not require lubricating and is quite easy to change the proportions of the oval.
It did not take too long for me to get my hands on one of these. Fascinating form of turning, that requires a different feel, look and attitude towards turning. First, you realize there is no longer a center point that a turned blank revolves around—no, it is a horizontal plane (that does go through the center) that you must work along. Sad to say you cannot go much above or below that line, otherwise you are working on another ellipse and you end up “deforming” the piece you are working on.
I had to learn how to do this type of turning pretty much by the seat of my pants—not a lot of commentary or instructions were out there when I started. I was lead to believe that you would have the best luck with scrapers. Problem was that at “normal” scrapping angles it was near impossible to get a nice surface finish on face-grain bowls and platters (especially in the end-grain areas). Looking at an old German textbook that had a chapter on oval turning, it revealed that gouges with shorter bevels held the promise. And so it was. Learning to position the tool to cut at the horizontal plane—and yes, rub a bevel—I could get almost as good a cut as on regular turning. Another critical point for my “60 grit gouge” friends: put away your power sanding—it does not work so well with oval turning.
I needed to investigate a couple of areas. One, could you do fine detailing in oval turning? The answer was yes, of course. I did small beads and cut lines into the face of plates and platters and along the rim of a bowl—it worked, but a little challenging. I also wanted to investigate “hollow oval turning.” A real challenge to work on the inside to get an even wall thickness. It works, but is slow going and a bit bouncy—and here my bent scraping tools had to suffice. The internal finish was not near as good as in “normal hollow turning” but showed real promise. I also knew that boxes had been turned historically: face-grain boxes turned out to be far more doable than end-grain—but I intend to run at that one again.
What’s next? I intend to develop the hollow forms as they seem to create a lot of interest when shown (one was so impressive that someone stole it from me at a woodturning event!!!!). Also, oval natural edged face-grain bowls has some real potential (effect of the oval plus the drying process that creates an oval—quite an elongated oval).
A while back the editors at American Woodworker had me out to demonstrate oval turning. They filmed part of the session and put it up on YouTube. Take a look to see a little about the process: http://www.youtube.com/watch?v=w5I2Yph57FI
I highly recommend that you visit Professor Volmer’s web site to learn much, much more on oval turning: www.volmer---ovaldrehen.de/englisch.htm