Turning a Large Birch Tree Trunk
It looks like we will be dealing with this Covid-19 virus for some time. I have been working in the wood turning shop nearly every day to keep my sanity and I am completely out of burls to turn. Soon I will be turning logs with interesting features like crotches and stresses which usually give interesting grain, but today I turned something unusual, the complete lower part of an old birch tree. A cross section slab was cut near the roots. The top of the slab in the photo is actually the part nearest to the roots of the tree. The average diameter of the slab is 23". My plan is to turn this entire piece end-grain.
I don't think many wood turners would attempt to turn this piece. There is a 5" deep bark inclusion in the center of the slab so his side will become the top of the bowl. This will also give a bowl with a nice unsymmetrical live edge. I attached this side of the slab to the head stock of the lathe using a 6" diameter faceplate. I created a solid foundation for the faceplate using a piece of ¾" plywood secured to the wood with lag screws as shown in the next image.
This slab was very heavy (23" diameter, 8" deep piece of green birch) requiring the use of my shop crane to hoist it onto my Stubby S1000 lathe. I used a rotating center in the tail stock to stabilize and secure this large piece.
Turning this large end-grain piece was slow going. The wood was spalted and punky in places. I considered stopping but decided to just go for it. On the first day I managed to turn the profile of the bowl with a 5.7" diameter tenon. The piece was still to heavy to reverse mount by hand, so I used the crane to lift, rotate, and attach it to the lathe with a chuck. Photos show the profile and the top, ready for hollowing. The bark inclusion will be removed in the process.
Hollowing was very slow going and took all of a second day. The Stubby lathe was very stable with no vibration and no stalling during the hollowing. Working with this lathe is wonderful. The next images show the completed bowl on the lathe in various views.
The bowl has an average diameter of 23", a depth of 5", and a wall thickness of ½". There is some spalting and interesting grain colors. It needs to dry and be sanded to show if it was worth turning this piece. Many areas are soft and punky which will require a lot of stabilizing and sanding. I applied some penetrating clear epoxy to these areas which will slow the drying but hopefully simplify the eventual sanding. Hopefully it will not wind up as very expensive firewood.