Heuer Reference 520

An odd column wheel timer and one of Heuer's finest stopwatches

When I first discovered my Reference 520 I was convinced it was defective. I pointed out to the seller the fact that the six o'clock subdial kept sweeping, regardless of any manipulation of the crown, meaning somewhere inside of the watch's gear train, something was badly wrong - I expected stop watches to, well, stop. In fact, I had come upon an entirely functional and very clean example of one of Heuer's finest timers. The lower subdial is meant to sweep all the time, as long as the watch is wound up. This accomplishes two things, first, it indicates that the watch is wound up and running (for this same reason ISO standards require a seconds hand on diver's watches) and second it makes the engagement of the timing mechanism much smoother and more precise. Engaging the stopwatch needn't start the mainspring turning and fire off the whole gear train from a standstill, as in a conventional stopwatch, rather, it only has to actuate the clutch to engage the column wheel mechanism and start recording time. In many ways, this is a chronograph movement without the time-of-day functionality, as both tap power from a mainspring and escapement that continue to run independently of the timing mechanism. This similarity is no coincidence as the movement is in fact a modified Valjoux 57, originally intended for high-end pocket watches that could be outfitted with complications as complex as a rattrapante. When new, the 520 cost double what conventional 30-minute Heuer stopwatch commanded and was more finely finished. My example has a chromed case with blued hands that look out of place with the rest of Heuer's 1960's lineup, which had begun to transition to brushed or even plastic finishes for their timing hardware.

Why would somebody have paid such a premium? First and foremost was the increased precision. For events that had to be timed accurately and may be impossible or very difficult to replicate, such as experimental chemical reactions in a laboratory or the finish in very close racing (more likely foot and horse than motorsport), this mattered. Although, for the latter, photo-finishes would have likely begun to render that concern moot. The security provided by the running seconds function was also very important in certain pursuits - knowing that the watch was working and ready to begin timing at moment's notice with a glance seems trivial until your submarine slams into the side of undersea mountain because the timepiece you were using to call your turns didn't start, or was running slow, when you clicked the pusher.