Duncan, why make the fly cutter from Aluminium? You need as much inertia from the tool as possible so it should be made from steel.
The aluminium will not be durable and could well distort around the cutter location.
Particularly when being clamped up hard.
As regards the cutters, buy or obtain some 6mm High speed steel cutter blanks and grind up to suit.
Best bet is search for a set of fly cutters in one of the tool suppliers as they are so cheap.
Clive
Edited By Clive Hartland on 15/10/2011 10:19:58