OldmanFCSA wrote:Hard Anodize in Eden Prairrie does excellent work, but you would still need to check the legalities of having this operation done there.
Then there is the problem of correct sizing of features before "hard anodizing" as it penetrates the surface about 0.001" and builds up on the surface about 0.001" leaving a surface that can only be diamond lapped to correct size if needed. Internal holes are a different story as size of hole will determine the amount of etching and plating. You may end up with oversize holes, or undersize holes that would need to be lapped to final size. Ensuring a correct size side to side would be difficult. Masking the holes is highly recommended here.
I may have to reconsider my decision on whether to join this venture.
I see what you are saying.......but any lower I have ever seen or used has all holes and features plated in hard ano - I have never witnessed a lower or talked to any of my lower mfg buddies that have plugged holes. I would be willing to bet that if you use an experienced lower anodizer and machine the holes oversized, a person wouldn't have any issues. BUT I could be completely wrong, as well.......

Out of curiosity, I am going to check one of my DPMS lowers with gage pins......will let you know what I find.