Feature B, the larger circular knuckles(8” diameter) on the large tabs are 3.2” thick to provide strength and stiffness for the main pivot pins. The walls connecting the tabs to the main ring are 3.0” thick.

The mass of the large tabs and their distance (9”) from the main ring call for the use of a feed pad.

The drawing shows the feed pad (in red) added to the wall to prevent thermal isolation and promote metal feed into the tab section.

The pads are ground off after casting, because they would interfere with fitting and articulation between the two plates.