Anybody Ever Drilled And Tapped A Ball Bering?

[whitmore]

Not entirely correct. Some aluminium alloys are found but aluminium on it's own is quite rare. You are probably refering to bauxite which is plentiful.

...contributes to lesions in the brain causing alzheimers...

Here is some more info:

https://www.atsdr.cdc.gov/phs/phs.asp?id=1076&tid=34

In referring to '8 percent', I meant that eight percent, by weight, of the Earth's crust
is aluminum atoms. They aren't atoms in native pure metal, but in other compounds.
Washita sharpening stones are nearly pure aluminum oxide, bauxite is just
the most economical ore for making pure metal.

The electron microprobes of Alzheimers' plaques that showed aluminum content, were
not finding metal, just atoms. The original findings have been traced to tissue preparation
materials, so the aluminum is not a likely culprit in the malady. It certainly is not
a known toxin.

The CDC link is full of guarded language, but one statement is clear:
"You cannot avoid exposure to aluminum because it is so common and widespread in the environment."

 

[samthedog]

In referring to '8 percent', I meant that eight percent, by weight, of the Earth's crust
is aluminum atoms. They aren't atoms in native pure metal, but in other compounds.
Washita sharpening stones are nearly pure aluminum oxide, bauxite is just
the most economical ore for making pure metal.

The electron microprobes of Alzheimers' plaques that showed aluminum content, were
not finding metal, just atoms. The original findings have been traced to tissue preparation
materials, so the aluminum is not a likely culprit in the malady. It certainly is not
a known toxin.

The CDC link is full of guarded language, but one statement is clear:
"You cannot avoid exposure to aluminum because it is so common and widespread in the environment."

Aluminium oxide and bauxite are not aluminium - aluminium is the metal in it's pure and refined state. To illustrate my point, you can ingest arsenic found in certain compounds reasonably safety because it is bonded, but this in no way means arsenic is safe. As this report states regarding aluminium and AD(Alzheimers Disease):

" However, recent reports concerning sporadic AD [12] and environmental [13] and occupational [14] exposure to aluminium have allowed the conclusion to be drawn that, under certain conditions, it is inevitable that aluminium will contribute towards AD [11] ; [15]. The suggestion is made that wherever in the brain the concentration of aluminium is pathologically-concerning (>2.00 μg/g dry wt.) that this aluminium will contribute towards any ongoing AD and will result in the disease being earlier in onset with a more aggressive aetiology [15]."
http://www.sciencedirect.com/science/article/pii/S0946672X16303777

Considering this report was published in March 2017 and has been peer reviewed by the medical community, the link seems pretty conclusive. Anyway, that's enough OT posts from me. Each person is responsible for their own health and safety.

Paul.