Note that foils only work if your drill can press down on the foil next to where it's going to drill, to keep it against the copper.
Message
Re: [Homebrew_PCBs] Re: How to deburr drill holes (vias) ?
2010-02-12 by DJ Delorie
Yahoo Groups archive
Message
2010-02-12 by DJ Delorie
Note that foils only work if your drill can press down on the foil next to where it's going to drill, to keep it against the copper.