How do welding shade numbers add up? Eclipse viewing.

you can not stack the lens, can still have severe damage, this is coming directly from NASA.

Direct from NASA, who also gave us Global Warming.
So, you're steering people into buying the cardboard and mylar eclipse viewing glasses from the Dollar Tree, are ya?
I'll take my chances with indirect viewing, thanks. Having used pinholes in cards before, I know it works and is detailed. Will try the binoculars this time, directed onto a card underneath, hopefully with a larger picture than the pinhole.
- I am a Transfinancial--A rich person born in a poor person's body. Please stop the hate by sending me money to resolve my money identity disorder. --anon

I think that saying "if you look at the sun for a moment, you will go blind forever" is bullshit. Similar to most anti-Trump bullshit, it is just ignorant dreck and propaganda.
It is meant to scare people in hopes that this scaremongering would prevent them from doing truly dangerous stuff, such as staring at sun for long durations of time. Similar to DARE propaganda and such.
Think about this. When you drive in the morning, evening, or mountains, you often get sun right in front of your eyes. And you still keep on driving. Surely, you did not go blind from that.
Similarly, there are many cases when you catch a glimpse of the sun, say, operating a crane, or doing some outdoor work overhead. I was craning stuff last week and the sun was right over where the hook was. It was extremely annoying and I tried very hard to look at it as little as possible. But still, the sun was right there.
I have no doubt that staring at sun for a long time (more than a second) would damage your eyes. It is uncomforable enough that people do not do that.
Now, welding shades are made for professional use to look at powerful electric arcs right in front of the person. They block most light, UV and such.
To say that a shade 10 is somehow dangerous, defies common sense.
I have shade 10 welding shades (with gold layer on the outside) and I tried them to look at the bright sun. They seem to work well, although the sun appeared to be a bit too bright.
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So I can double up on 2 #11 weld lenses & Im safe?

I think it was about 10am that the smoke rolled in from a nearby fire today. Hopefully, the air will remain clear past 9:19am tomorrow.
- I am a Transfinancial--A rich person born in a poor person's body. Please stop the hate by sending me money to resolve my money identity disorder. --anon

[ ... ]
Well ... start with counting the passes of drawing wire through reduction dies. (They *are* "wire sized drills" after all.
Then, start moving some sizes a bit to avoid near fractional sizes. (I think that the only counter-example is #7 = 1/4"). This helps make a number of sizes between the two series. The next thing is when metric sizes came into the game so move things a little more to make the combination of wire sizes, fractional sizes, and metric sizes fill in most of the gaps in the individual sets. Note that when using roll taps in imperial sizes, the recommended tap drill is often a metric size.
Enjoy, DoN.

-jsw