Hard point in the worm.

Alas, it could have been a perfect purchase because the hardware is well designed, practical, efficient, adaptable on multiple media, but I came across a copy that has a hard spot in the rotation of the main screw without (one that allows to adjust the clamping force of the bite) .. this is unfortunate since this makes it difficult for clamping precision parts (I do not know, sometimes, if I have enough tight or if I fell on hard point).