Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

Not mentioned so far in this round, is the technique of allowing for
the side etching of the trace in your pattern design.

Depending on the copper thickness and your etchant chemistry you can
compensate for the undercutting of the etch resist.

So to achieve 5/5 reliably, depending on the under cutting at your
place, you may have to set your design rules to 7/3 (1mil per edge
undercutting)or 6/4 (0.5mil per edge undercutting)

Regards