Spend the 20 bucks or so for a copy of "Aircraft Structures" by David J. Peery. Start working through it. You don't have to go all the way through to get yourself to a point where you can calculate stresses on a roof truss.

Get a copy of your local building code so you know how much load it needs to carry.

Once you're there, do the calculations and see if you're comfortable with the result, make up a test article in the back yard or garage and put loads on it (load it to whatever code requires and see how much it deflects, then load it until it breaks to know how much margin you have) to be sure, and then modify away.

You could try one of these:

https://www.irwin.com/tools/locking-tools/the-original-locking-wrenches

It bears at three points and is designed for dealing with really stuck-on flare-nuts on brake fittings and the like.

An alternative would be to take a Dremel to it and grind it into a regular hex nut then use a wrench on it.

In other words you put your foot in it and are now blustering to save face.

Only in your mind. This started with the utility of water on Ganymede for space exploration. Nobody said anything about "mining asteroids".

Doesn't matter what they were used for, they didn't magically produce water from vacuum. The hydrogen and oxygen were carried from Earth on the spacecraft.

So you've visited every rock in the Solar System and peformed a chemical analysis on it have you?

OK, what "useful chemical process" makes water out of hard vacuum.

All the hydrogen and oxygen in those fuel cells was carried into space on top of a Saturn V. And it all burned up when the Service Module reentered. It is no longer available in space. And in any case, Apollo did not go to interplanetary space.

Read up about orbital mechanics.

Many people make the assumption that DNA is the only possible carrier for a genetic code. If whatever life we find on Mars or Titan or elsewhere has a different molecule as the basis for its genetic code that would be pretty strong evidence that it didn't originate on Earth.

Every drop of water on a space station has been carried there by humans in some form or other. And every gram of hydrogen and oxygen that are expended as rocket fuel in interplanetary space is pretty much nonrecoverable.

This looks like some idiot removed structure to get clearance for ductwork and when he realized that things were about to fall on his punkin' haid rigged something to keep it from happening long enough for him to get paid and skip town. You really need to get somebody who knows what they're doing to eyeball the situation and tell youu what needs to be done in the way of a permanent fix.

Is the display balanced? Doesn't have to be exact but the closer it is the easier it is for the motor to turn.

https://www.americanpoleandtimber.com/wood-timber-products/challenge-course-zip-lines-ropes-course-materials/ looks like they have what you're looking for. They say they have posts up to 52' long and 20" diameter. How much they charge I have no idea.

I don't think he's talking about designing a commercial coffee machine, I think he's talking about a one-off hobby project.

And people do pay that for coffee machines. A Jura Giga 6 is about $6000, a Z10 is around around $4000. Neither of those is considered to be a "Pro" machine.

If you don't want to change switches, Hue bulbs and hub work fine. If you don't mind changing switches then Lutron Caseta and its associated hub. Either way you can trigger with a motion sensor, your phone, Alexa, or any number of other options.

Tell your Dad. It's not something you did unless there's something you haven't told us. He might be able to fix it or he might call an electrician. But don't you try to mess with it unless you're sure you know what you're doing and meaning no offense if you have to ask this particular question here you're not sure of that.

If you want to know how to deal with it going forward, ask whoever fixes it if you can look over their shoulder and ask questions, and if they say OK, then look over their shoulder and anything they do that you don't understand, ask questions. But don't do that until you're sure they're OK with it--some tradesmen love to take a teaching opportunity, others don't like to be watched.

If I'm reading it correctly the 1997 MRI standard for commercial shelving says to test to 1.5 times the design load, measure the deflection, leave it under load for 15 minutes, and measure the deflection again. If it increases by more than 5% in 15 minutes, or stays deflected more than 15% of the final deflection after the load is removed, it fails the test.

http://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=1000&context=ccfss-rmi

There's a newer standard but it doesn't seem to be available online.

If your mirror weighs 112 pounds you would want to test to 112*1.4=168.

Personally I would test with milk jugs or something (figure a gallon jug of water is 8 pounds, a 5-gallon bucket is 40 pounds) rather than standing on it--if it breaks, water on the floor is a lot easier to deal with than broken legs.

You can get epoxy and milled glass by the gallon. Total Boat is a popular supplier but they seem to be out of the milled glass--Aircraft Spruce seems to have stock on the milled glass.