Jeff Gorman wrote:
> [...] This includes the possible risk of the wheel exploding, or
>(remotely?) the mandrel being shaken off the lathe centres. The former
>has happened to somebody I worked with. He was experimenting with a
>home-made device, but fortunately he was not in the direct line of
>fire.

To follow the "exploding grindstone" thread a bit:

On one of his shows St Roy tells a story about cleaning up
an old grindstone.

The stone was badly glazed so, to clean it up, he soaked
it in gasoline.  After it was finished he got the gunk off,
and then set the stone aside to dry out.

Later, he set the stone up --on a treadle base, of course--
and started to use it to sharpen a chisel.  However, although
the surface was dry, there was still gasoline buried
deep in stone.  The centrifugal force of the spinning started
expelling a thin, atomized mist of gasoline surrounding the 
area of the stone.  His story ended about the time he touched 
the blade to the stone...


So, remember, be careful out there; it's a jungle.

N