Monday, October 29, 2012
Michael Poorman was the closest (and only) guess to the technique. Here's the answer with the trick. The blank started out as a cube. I sanded off 2 of the corners of the blank to give the drive center and live center a flat spot to register.
The blank is then mounted on the bias, essentially corner to corner (except I've sanded the corners off to make it easier). The 6 remaining corners will be the corners on the ornament. 3 on the top wing and 3 on the bottom wing.
With the lathe spinning this is the shadow of the blank. You can more easily see how the 3 corners on the top and the 3 corners on the bottom are aligned.
The upper surface of the upper wing is turned first. I also shape a small tenon that will be used later.
Then the under side of the upper wing can be turned. I've left it a little thick at this point, it can be thinned and refined later.
Next the blank is flipped end for end (I'm VERY right handed and always prefer to work from the tailstock side) and the process is repeated for the lower wing.
Now the shape can be refined a bit and a tenon formed on the bottom end. There are now 2 tenons and the wings are basically formed. They may still be refined slightly but most of the work is done.
The tenon formed above can then be gripped in a chuck (I'm using a Supernova2 with a set of Pin jaws, they'll grip a tenon between .4" and 1.22" diameter. This gives free access to finish off this wing.
To finish the other wing I had to get a little creative. The smallest vacuum drum I have is 2" diameter, it was slightly too large for this piece. What I decided to do was to thread on one of my drilled and tapped jam chucks, round over the face, and then apply some closed cell foam (yellow). With the center cut out of the foam I was able to get just enough pressure to finish off the piece. The other tenon was removed and the wing thinned and refined. I then drilled a hole through the middle to receive the cap and the drop finial.
And the finished piece.
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