Hi all, I’m currently in the process of ordering parts for the SatNOGS v3.1 antenna rotator and am trying to avoid international shipping due to costs. I’ve been looking for inner bracket B-type slot 6 (Innenwinkel Stahl 20 B-Typ Nut 6) and t-nut B-type slot 6 (Hammermutter im B-Typ, Nut 6 und der Ausführung M4 bestellen) hardware components but haven’t had much luck with US-based distributors, as they typically have different dimensions. Has anyone else found these components in a US-based distributor (at a reasonable price)? Any help would be much appreciated, thanks!
Turns out the fastening hardware was most expensive part of building my v3.1 rotator 
Anyways, I just ordered my t-slot hardware from Amazon, free shipping in US (with Amazon Prime).
Thank you so much, this really helps!