It wasn't until 1959 that the yard was metricized. This still affects precision machinery manufactured before the changeover.
It was metricized with all the rest before that. What happened in 59 was harmonization with other countries including Canada, who had a different agreement on the metric yard. The older american definition was 1 yard = 3600/3937 meter. The international metric yard is exactly 0.9144m. (A difference of 0.002mm)