While finishing the cone mandrel, just posted, I was working on this, as well as other things.
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Perhaps you can say what the spike is? I think it is a marlinspike.
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Something else salvaged! Too good to waste.

This is why I want a bick and a cone mandrel.
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See, it gets in nicely round the spiral arms. This spiral was started while the bolt was heating, and continued afterwards.

I found a couple of scrap flat pieces, one of which had a hole which was a loose fit on the spike, welded them together after drilling a hole in the other bit for the tapered pin, which locks the assembly.

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A brass ferrule from an old tool handle over the spike makes a tight fit.