Thanks again Robin,
to say I got 10 micron accuracy would be overstating things somewhat, .... I crept up on it over the last 3 cuts!..... but it was round.
The swarf is a problem, I like the idea of a proper unit to keep the mess in, could go for a bigger machine, a power saw, grinder........mmmm.
I will look into that.
Must finish this one first though, more progress this Easter I hope.
Cheers