Punch double-D hole for 5-way binding post

[johnnyreece]

I don't know what tools you have, but if money were no object and I couldn't find the exact right thing, I'd get a 1/4 square punch, then file (or dremel) the top/bottom of the hole. To me, the perfectly straight, flat sides are harder to get than the round parts. Or, depending how often you might use them in the future, make a template that you could use a dremel with some kind of bushing, like people do with routers and templates. I dunno. The magic answer of a purpose-made punch doesn't seem like it's in the cards. Maybe a local machine shop could do something?

[sluckey]

Only 4 holes? Get a jeweler's file set and one beer.