Base Board Thread Issues

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.

Hi @sspw ,

Can you send me some photos and also the order number. You can send it to me as personal message here in forum or send directly here in our support page.

I just received some new 19007 boards yesterday, and the screws went in with zero resistance as expected.
I will try getting some pics for the problematic 19001 board issue for tomorrow.