Coring Bowls

by admin on March 7, 2010

coring a bowl on the lathe

I met a wonderful man in Etna, New Hampshire. He lives just up the road from my daughter and she sent me a newspaper clipping about him. A rugged individualist, he graduated from high school and decided he wanted to turn bowls for a living. He as been doing just that ever since His specialty is turning beautiful burled wood bowls and the newspaper article showed him with a burl so large that it had to be pulled off the pick up truck with a tractor. After reading the article I wanted to visit his shop. He very generously ended up spending the whole afternoon with me and even gave me a lovely log of crotch butternut to take home.

I had been reading about coring bowls for a long time. It seemed a bit complicated and there were several types of tools to choose from. I turn a lot of bowls and this produces a lot of shavings from removing the waste wood from the inside. I know this because I have to bag and carry out these shavings from the shop. My neighbors and friends are just about saturated with free mulch and I put as much on my garden as the earthworms will eat.

So when I visited my New Hampshire turner, whose name is Dustin Coates, I asked his opinion about coring tools and techniques. His reply was to core a bowl on the spot for me to see. It was amazingly simple and looked rather easy. Using this technique one can get two or even three bowls from a single bowl blank. It results in a saving of valuable wood. Often I would lament that I had turned the prettiest part of the wood away in removing the wood that had occupied the cavity of the bowl. If you sell bowls, as I do, then it produces extra income from the same amount of wood. Actually I found it took less energy and less time to core a bowl than to dig all the wood out with a gouge. Last but not least, it dramatically reduces the amount of wood shavings left over after the bowl is completed.

My friend, Dustin, suggested that I get the McNaughton system and which of the many sized and curved cutting tools were most useful to him. He even suggested that a pair of vise grip pliers would substitute well for the more expensive handles and you can see me using his suggestion in the top photo. What I really like about the system I purchased is that you can match the curve of the coring tool to the outside dimension of the largest bowl blank. This gives you more flexibility in determining the most aesthetically pleasing shape of the largest bowl you get from the chunk of wood. Some coring systems I have seen limit you to the same shape which is half of a sphere. This is fine if all you want to do is make a set of nesting bowls but but if you want to create designs with more subtlety and variety you need a system like McNaughton.

It is interesting to me how we are always searching for more. That is just the nature of life. I wanted more bowls, less waste, less work and less shavings and now I have all four. Yet I did not have to sacrifice design considerations to achieve this. How nice it is that at just the right time there is someone more knowledgeable than you who is willing to share what they have learned. It saves you valuable time and energy by preventing you from going down less productive paths.

cored bowl

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Eye of the Beholder

by Edwards Smith on September 6, 2009

When I was living in Lexington, Kentucky I got a call one day from a friend who said that there was some wood available in the little town of Midway, just a few miles away. Midway is an old and charming little town in the heart of the bluegrass region. I called, and a dentist who owned the land said that I could have some wood.

It turns out that the land hosted a late 18th century inn called the Porter House. Most have heard of a porterhouse steak and that is where it originated. The inn now serves as a dentist’s office and residence. The tree was a mammoth silver maple. The neighbors had complained that if it fell it might damage nearby structures. So it had been cut down. I have no idea how old the tree was but I would estimate that it was over 100 years old.

When I drove into the alley that separated the Porter House from the neighbors I saw an array of bolts of wood with grass grown up around them. Some had fungus actively growing on them. It did not look very appealing to the casual observer. The rounds of wood were so large that I had to saw them in half to be able to lift them into my van and even that was an arduous task. The fresh cut wood surfaces smelled musty and were mottled in their appearance. When I had loaded all the wood I could carry I headed back to the shop to cut some bowl blanks and rough turned them.

What I was dealing with was spalt wood. This is caused by fungus attacking the dead wood. When alive, the tree’s immunity protects it from bacterial and fungal decay. When it dies, these microorganisms go to work to reduce the wood to carbon dioxide and water. Without these necessary aspects of nature, all the wood and leaf litter would stay with us and I don’t even want to think about the fire hazard that would make. The fungus can cause the wood to be black in areas due to formation of fungus spores. In other areas it blanches the natural color of the wood. The final result is very interesting color and pattern variation in the same piece of wood. The black lines may follow the wood fibers and reveal a wavy pattern.

In the past, timber men would regard this as a defect. Spalt wood is softer and less stable than the normal wood. So it would have been relegated to the fire wood pile or just left for the fungus to finish the job. It is not even considered good fire wood because some of the energy stored in the wood has already been consumed by the fungus.

Spalt wood is definitely harder to work than the same wood which is free of decay. It requires a softer hand with the tools and produces some design limitations. Sometimes it just won’t do what you want it do do and the piece must be discarded. However, I think it is well worth the effort for the visual display it produces. People seem to be naturally drawn to the color and pattern variation.

I got several large bowls rough turned from the damp wood and put them in paper bags with the top sealed so that they could dry more slowly to avoid cracking, or checking—as woodworkers call this tendency of wood to split itself apart when it dries unevenly. The rest of the large pieces I covered with a tarp and left to fend for themselves.

Eventually I moved along with my wood to Maryland where I live now. At a show I sold one of those large spalt bowls and the purchaser became my first collector. He and his wife purchased two more bowls from the same wood and then commissioned some large candle holders to hold three inch pillar candles. In the pictures above you see the rough forms before they were turned as well as the finished products. I treasure the remaining pieces of this wood and have turned some of it into wooden jewelry.

So what would be considered trash in another era has found a place of respect with those who appreciate the infinite variety and creativity of nature, even when it is tearing down and not building up. Beauty is in the eye of the beholder. If we have a limited vision of utility, we may overlook some of nature’s hidden treasures. When we are open to all possibilities then we find riches in what others would discard.

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