An optical bypass relay can improve the reliability of a repeatered fiber optical computer network. Previous relays suffer from low cross talk isolation, high insertion loss or limitation to single-pole-double-throw operation. We describe an opto-mechanical fiber bypass relay with one moving part. The relay makes use, during assembly, of the fibers themselves both for mutual alignment and as temporary alignment tooling. This eliminates the need for individual alignment of each relay during assembly. Prototype relays exhibit -52 dB cross talk and -1.7 dB loss and ample life expectancy for their intended task.