Hey Berttt, try looking at the model magazines in the old forum. There were a few different examples for the arm joint.
http://www.macrossworld.com/macross/magazi...02-hj-page7.jpg
http://www.macrossworld.com/macross/magazi...02-hj-page6.jpg
http://www.macrossworld.com/macross/magazi...h_feb02_j-5.jpg
http://www.macrossworld.com/macross/magazi...02-dh-page8.jpg
http://www.macrossworld.com/macross/magazi...02-dh-page6.jpg
Hagan