After seeing this pdf I decided to make a pin chuck.
http://www.penmakersguild.com/articles/pinchuck.pdf
In fact I've made several of different sizes as and when I need them. They are very simple to make, specially if you have access to a small metalwork lathe.
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This was the first I made, and I didn't turn a ridge into the shaft to stop the blank butting up against chunk of ally it's embedded in. So I simply push a small bushing on there to achieve the same thing. All the ones I've made since then have a built in stop.
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Simply put the pin in the channel and slide on the blank.
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The rotation of the lathe spins the pin to the edge and locks the blank into place while you shape it.
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