Turned wood inside out ornaments give me a certain fascination. Turning one presents some difficulties and risks — all of which can be quickly resolved except one.
The most difficult part is visualizing the empty space to be created inside the ornament. I’ve tried to model it. One thing that has worked the best is to make a turning with 1/4 inch steps every 1/4 inch. Then when reversed and turned, some visualization of scale is possible.
To begin, an inside out blank is constructed from four perfectly square milled pieces of wood. Some turners put craft paper in the joints and glue the entire surface. I don’t like the clean up that results when I need to rotate the blocks. Instead, I glue only the last 1/2 inch. To ensure the block does not fly apart on the lathe, I use a band clamp around each end. Small arcs of wood serve as cauls to avoid kinking the band clamp. Then I duct tape the band clamps.
Then turn what will become the center void. Avoid tooling anywhere except where you want the void since any tooling now become part of the center void. Then sand and finish now while you can.
To separate the four pieces of wood, part off the last 1/2 inch of one end. They should now separate fairly easily. Little if any clean up is required.
Rotate each piece to put the outside into the inside. Glue the new inner surfaces with white glue and clamp together. Clean off any squeeze out now.
Carefully turn the exterior. Pay particular attention to the four thin corners that will become thin slats and be like sharp knives. These are both fragile if too aggressive when turning and dangerous if they contact fingers while turning or sanding.
Add finials and a center feature.