Screw it! Close enough, I'd say. We all know you'll put a caliper on it eventually. One of last year's winners had no functional brake (drum brake but no rod or cable connected to it and no lever or pedal) and no paint; I mean no offense to that member (he did fantastic work, BTW), just pointing out that at least one unfinished bike has been considered finished. I just checked this year's rules and there is no mention of brakes being required; just wear sturdy boots when you make your ride video. You could have made a dummy caliper, whittled from wood, molded KBS epoxy putty, or whatever, and nobody would have known it wasn't functional. 10 bonus points for honesty!