We have a multiple RAK19011 and a few 19007 base board where the screw only get about 1/2 in and start to seize. One batch of 19001 is particularly problematic get screw in safely!
There appears to be a coating or contamination on these internal threads. When the screw gets about 1/2 to tight, the coating is blocking and seizing further safe travel. When i back these screws out, the holes are blocked, with some “varnish like” material. Where there was a clear looking hole before the screw, the hole is blocked.
Its not cross threading. There clearly is a “varish like” material being pushed out of the thread and piling up ahead of the screws.
We have been careful, but we have sheared the heads off a couple screws.
We tried screwing in the screws, like tapping, 1 turn in, 1/2 back, but it not realiable.
I would like to know what the material is and if we can use some cleaner/solevent to prep those internal thread before attaching modules.