I am thinking if it's possible for craftsmen of late medieval times to achieve precision required to repeatedly make crossbows enhanced by use of cams or pulleys. As far as I know, pulleys were used in medieval societies quite often, but I don't think they were made in sizes approaching the ones required for compound crossbows. But, assuming some medieval scientists figured out putting pulleys on ballistas or crossbows would bring some advantage and then found some skilled craftsmen to build parts and find good materials for it, would it be plausible?
Edit: 
It's true that my question is really similar to this one: https://worldbuilding.stackexchange.com/questions/67446/rambo-style-compound-bows-feasible-with-renaissance-tech-level 
but I believe this earlier thread was a bit more specific on a compound bow specifically (with features like detachable arms) and I think that answers provided under my question give some new information and thoughts on the topic.