This is actually an answer to a thread that was recently "protected" before this answer could be posted. I've tried various saw blades on FR-4 but it dulls them too quickly. A hacksaw works but I found a better way: a carbide tipped tile scoring hand tool. See photo. I etched my board first so I was cutting sections apart along separation lines, so I'm not sure how well it does cutting through the copper itself. I believe it will do quite well. Procedure: hold a ruler along the path to cut, score lightly with the tool, move the ruler, and follow the score repeatedly to deepen it. You can go deep enough on one side to break the board, but I recommend scoring both sides. (You can score all the way through, of course.) Use a diamond-dust hone (coarse grade) to polish the broken edge. The kerf is about 2mm+ if done one-sided, less if scoring both sides. Really rips through and doesn't get dull.
closed as not a real question by Rocketmagnet, Leon Heller, Phil Frost, embedded.kyle, Olin Lathrop Feb 27 '13 at 14:37
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