.003” (76 microns) would be a large tolerance even for mil spec thick hard anodising. More likely 50 microns at most.
Ordinary cosmetic coloured anodising would be no more than 25 microns thick. (that’s just .001”), and probably much thinner, even as thin as 5 microns. And by some early accounts, it is on the thin/soft side.
Then, the rule of thumb is that the anodising thickness is 50:50 build-up vs. reduction of the metal. I.e. if looking at the inside diameter of a tube, even a top-notch mil spec thick hard anodise might result in no more than 76 microns overall reduction, compared with the thinnest cosmetic treatment. That’s an improbable absolute most, and that’s being generous.
https://metalfinishingsltd.co.uk/articles/anodising-dimensions/
0.4mm actual difference ? That’s an order of magnitude worse than even my most worst case 0.07 mm estimate. So no, this theory doesn’t work. It does not explain the large difference in dimensions being reported.
I would suggest that these were two separate batches of tubes, machined slightly differently (I could also speculate why, but am trying to stick to only the facts and data that are beginning to build here, as precise people begin to receive theirs, and maybe post more photos).
Then anodised as separate batches (the colour dying is the second process (followed by the sealing) after the actual anodising, so no reason why a single run of tubes and other pieces etc. could not have all been machined in one run, then run through the treatment process simultaneously, with only the secondary dying and sealing different, as the final steps.
More flexible too, when you are only offering pre-orders, and not sure what the proportion of the two colour choices (nor emitters) will turn out to be.
Initial photos showed a hybrid colour scheme, black head and tail, champagne tube, which would have solved any colour mis-match issues, but turned out not to be popular.
Really not being negative here, just trying to reach out to FF to help them consider some basic stuff, and maybe make a few suggestions to those already with them, or on order.
Isn’t that why FF are offering BLF these first things first, to “kickstart” a run, shake out the bugs, get some revenue, hopefully generate a good buzz ? I’d hope they are in the mood to listen, and learn, and react swiftly, though it might seem a bit overwhelming to them at the moment. If so there could be a great future ahead.
It’s only their second attempt, after all. This is still recoverable.