On the subject of powder coating or wrinkle coating, it might surprise you the number of times I have encountered cheesplates or like threaded elements that have been coated without consideration to the tolerances of the bolt. This often ends up with a need to re-tap the freshly coated objects such that a bolt can be accommodated.

Many of the elements tend to be chemical dipped / treated I believe due to such issues.

Thanks, we will keep that in mind :)