On Tue, 02 Sep 2003 21:07:18 +0100, Matt Helliwell
wrote:

As you clearly know more about the subject than me(!),

All I know is that every cyclone I've built (and the first one was a
plastic bucket and gluegun) has worked. They're just not hard.

can I use the 3"
dust extraction pipe work, blast gates etc. that Axminster sell.

Probably, but it will stop working if you go too big (although I've no
idea where "too big" is). I seem to be managing well with 2" and I
wouldn't want to go bigger. I sweep up handplane shavings with a
broom, but the 2" pipe sucks up all the other waste without blocking.