how important are thru-holes? my friends and i are making a cheap desktop circuitboard miller. it mills away the copper with a blade rather than etching. it ca

how important are thru-holes? my friends and i are making a cheap desktop circuitboard miller. it mills away the copper with a blade rather than etching. it can do both sides of the board in series, but no thru-holes. is this something anyone would be interested in?