While participating in hand planes discussion on some non-English speaking forum, somebody has questioned material choice for the collar that holds the blade on Veritas Large Router Plane. That somebody claims to tighten the blade hundred times a day and that this high load eventually damages the thread in aluminium (aluminum) collar. And after that discussion went on regarding other parts on other hand planes from the same material and then to comparison to bronze lever caps on other well-known hand planes. My load is nearly absent and had no problem, so, I cannot relate to that.
I couldn't find any discussion about that but I'm sure there must be some reasons to choose one material over the other. Just wonder what they might be. On the other hand, Lie-Nielsen Router Plane has no aluminium parts.
I did find Derek's post about piston in the collar screw and mentioned it on that forum, maybe that is the actual problem...