Opinions sought on cheap desktop PCB milling machine

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I tried standard engraving tools from suppliers in U.K., Poland and China in various angles from 30 degrees to 60 degrees, but were unable to get the 0.25mm traces and 0.25mm isolation that I wanted. 60 degrees was better than 30 degrees - cleaner edges and fewer burrs.

I came across spade mills on CNCZONE a couple of years ago and have not used anything else since - there is little burring at 20,000RPM and the life is about twice the standard type. I can easily get 0.25/0.25mm and have got 0.17mm track and 0.13mm isolation in trials - but not used on working PCB.

You can get them now from :- http://www.drewtronics.net/

Mike