The reasons why in case we decide to issue a lot of cranks to be manufactured, it should take much less time than the prototype did, are exactly the reverse of why it took so long to make the prototype:


as running a batch would make sense to spend more time in a even more accurate setup of the machines, and allow for more wastes in the process.

Similar considerations do apply to any other part we wish: special tools are not already made but in any case, if we ask to run a batch of... "anything" it should be done much faster, cheaper and better than if I ask to do a one-off piece as a favour.