jeudi 5 août 2010

woodturning lessons - Nine Things I Wish Somone Had Told Me



by Jon Siegel


After more than four decades of woodturning, it is difficult for me to remember how I first learned. I do remember seventh grade shop classes and also my father showing me the little bit he knew. Mainly, learning was by trial and error. As years went by, I got better at it, partly because I was exposed to some good books such as the classic by Frank Pain, The Practical Woodturner, but it became clear to me that woodturning was an obscure specialty. Many of the tools I saw in old books were not available.

Today woodturning is no longer obscure. The woodturning renaissance has had 30 years to mature – we have the American Association of Woodturners and hundreds of books and instructional videos. As a result, no one has to learn by trial and error in isolation as I did when I was a kid starting out in 1960. Nonetheless, in this article, I will attempt to help beginners not by giving simply a set of “tips”, but a list of items which fall into one or more of the following categories:

• Things I did incorrectly at first, and later had to “unlearn.”

• Things I should have learned sooner rather than later.

• Things I had to figure out on my own, because they were not in any books I had seen.

While I will jump around to many different topics, these represent some of the high points in my odyssey of discovery.

1 CUTTING VS SCRAPING – I wish my seventh grade shop teacher had said to me, “I’m teaching you the scraping method because you’re a beginner, but someday when you get serious about woodturning you’ll learn the cutting method.” If he had done so, I would have realized from the start that he was sending me down the wrong path.

Twenty years later, I found myself teaching shop, and I quickly discovered that you never learn something so well as when you must teach it. I developed this educational philosophy – don’t teach beginners the wrong way just because you think it might be easier for them to grasp. This does the students a great disservice and insults their intelligence. Show students the right way from the beginning, and be honest about the commitment required.

It’s easy to criticize my shop teacher now, but I don’t think he was purposely keeping anything from me. Rather I suspect he was not in possession of that information. In those days, industrial arts textbooks described mostly the use of scrapers. Gouges were used only for roughing out spindles. Many of these textbooks were written by authors whose expertise was mainly in metalwork and pattern making.

2 A LATHE IS NOT A VISE – I once read in what I thought was a reputable magazine that the wood should be placed between centers and the tailstock tightened as hard as possible! Yikes! Excessive force from the tailstock causes a multitude of problems – premature wear on the headstock bearings, premature wear on the tailstock center bearings, and most important, vibration of the workpiece. It took me a long time to realize that excessive force between centers was a major contributor to workpiece vibration of long thin spindles. A well tuned drive center with sharp spurs (as sharp as a chisel) and a center point that is just the right length (or on a spring) will allow turning with minimum force from the tailstock.

3 THE WOODTURNER’S BEST FRIEND – Paraffin wax, sold at grocery stores for canning, makes an excellent lubricant for your tool rest. Break each bar up into small pieces so you have one within easy reach around your lathe. Use paraffin on the tool rest every five or ten minutes. Use it on the lathe bed too. Everything will go better. Paraffin is much more convenient than paste wax from a can.

4 YOU DON’T NEED MANY CHISELS – I wasted a lot of time and money buying chisels I didn’t need. As time went on, I realized that there are only about five chisels for spindle turning, and another five (bowl gouges and scrapers) for cross-grain work, that I really need. The chisels I no longer use are mainly the large ones. Refer to my article in the June, 2005 issue of The Old Saw for suggestions on the essential chisels.

5 YOU WON’T GET FAR WITHOUT A STEADY REST – Frank Pain’s book introduced me to the technique of using my hand to steady the work and reduce vibration. As an unexpected benefit, I also learned that touching the work with my fingers can tell me things about the quality of the surface which my eyes alone could not detect. But for a long time, the flexibility of spindles was a limiting factor in my furniture designs. While I consider use of the hand to steady the work an essential skill, it will only go so far. Once I got a good mechanical steady rest, I could cut as deeply as I wanted, and my turnings instantly improved.

6 SHARP TOOLS PLUS GOOD TECHNIQUE EQUALS LESS SANDING – In my early years, I thought that it didn’t matter much how you got the shape, because in the end you could sand the work into submission. The lesson, which came gradually, is that less sanding is better for many reasons – sanding is boring, sanding dust is horrific and sandpaper cost money. But most important, the work looks better with a minimum of sanding because the surfaces are true and the details are crisp.

7 YOUR LATHE NEEDS SPEED CONTROL – Years ago, most lathes had step pulleys with four speeds – fast, faster and two more even higher speeds which were so ridiculously fast that no one ever used them. So essentially we had two-speed lathes and used the low speed for bowls and the second speed for spindles. Today, lathes with step pulleys have five or six speeds, but the problem has not changed. The lowest speed is not low enough and the high speeds are still ridiculous. In general, all these lathes would be better if the speeds were cut in half. Variable speed mechanisms are a great improvement, but variable speed motors with two or three speed ranges are ideal.

8 FLAT GRIND – One day I discovered that chisels ground with a flat bevel work better than those that are hollow ground. I quickly re-ground all my cutting tools to the new flat grind, and I have never looked back. It’s hard to describe the feeling of that day. Without buying anything new or investing additional years of practice, I had suddenly made great progress in my ability, and I was seeing results that amazed me. If you attended the lecture by Michael Dunbar last September, you may remember he said the same thing about draw knives, scorps, etc. Any tool which is guided by riding the bevel should not be hollow ground.

9 THE JOY OF WOODTURNING IS DIRECTLY PROPORTIONAL TO THE MASS OF YOUR LATHE – This is not to say that I don’t like mini-lathes, I do. Any lathe that is built with all its parts in proportion with each other will function well on work pieces that are also in proportion to its size.

Back in the 70’s, I was fortunate to get a used Blount lathe (made in Milford, NH) which weighs about 500 pounds. My experience with that lathe resulted in a great leap forward. In particular I think having a well designed tool rest on a 300 pound cast iron bed made me realize how turning should feel. Now I have three lathes at 50, 500, and 5,000 pounds, and the Blount holds the middle ground.

Whether you are learning from books, magazines (like this one), videos, classes, or symposium demonstrations, be thankful that today there are so many resources and such a tremendous body of knowledge on woodturning to carry you on your own personal odyssey of discovery.

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