I need some expert opinions with some trouble we are having with determining the best way to manage the ISO requirement for measuring with calibrated instruments and the cost effectiveness in our situation. We are manufacturing components with Acme threads for valves purchased from our vendor in China. The problem is that we would need to purchase $500K worth of Go/NoGo gages to cover all of the threads that are being used. We are researching the highest use threads and will probably purchase gages for them, but this leaves many others without a gage. We have been gaging them with a mating component, but this does not meet the calibrated requirement. We have discussed using the 3-wire method, but we have limited employees that are trained or competent enough to be trained. This also would not solve the issue for female threads. Due to the low volumes of each thread type being manufactured, we would like to continue using mating parts, but I am struggling to find a justification or measurement method that will satisfy the ISO requirements.