You're probably right that this is the simplest way for you to run the plug. My recommendation is that before you touch the door with the drill, you make the hole in some scrap wood. To be absolutely sure your plug head will fit through and your hole plugs will fit.

If you want to try at a more elegant wall solution, this old reddit thread has ideas: https://www.reddit.com/r/amateurradio/comments/hsv7zr/internal_wall_pass_through_for_coax/?utm_source=share&utm_medium=android_app&utm_name=androidcss&utm_term=1&utm_content=share_button

It's safe to cut it out, removing one interior stud won't make any difference.

And beer for said friend

It's a dumb idea to drill a .75" hole through a door to run a wire.

You can buy similar toggles at most big box hardware stores as well. I get them from home Depot.

You can try to fix it or just scrap it and take advantage of the heat pump water heater tax credit if you’re in the US.

The valves are like the most expensive part of the heater. You can purchase them separately and they are fairly simple to install (if you are familiar with plumbing). Considering the age of the heater, you may be better off replacing the complete unit.

They don't bury this. They scoop it all up and haul it to a landfill. That picture you have of the washout, should also be lined with plastic sheeting because wet concrete is hazardous.

I use those anytime I have to hang something heavy. I’ve had heavy items in my home hanging on them for ten years with no issues. Second this recommendation.

I've used it on 2 full ceilings and a few wall cracks, it is amazing

Pressure wash.

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Reduced shank drill bit is what you want. Mcmaster Carr has them and everything else.

You can also chuck it backwards in a drill it does fit, and then spin it and grind the shank down, if you're careful to keep true it will work ok- a poor man's lathe.

Hollow-core doors are not really hollow. It is more correctly corragated-core, as there is usually a skeleton of cardboard criss-crossing inside the door. in other words, the foam won' t be able to spread out.

Take a picture of the lid and label

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Appliance dolly.

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2 wheel dolly and a friend.

Yeah it’s a 2x3. It’s very close to the original 2x4 stud. Basically the original side of the wall was kept and the other side of the wall was replaced with drywall, only, the drywall sections were not cut to line up with the original studs. So it has these 2x3 studs to hold the drywall together. I guess I’m just worried whether cutting out the 2x3 will weaken the rest of the drywall.

Get a different bit. Like this.... https://www.acehardware.com/departments/tools/power-tool-accessories/drill-bits/2401644

It is often very cold (even more so when I'll likely be using it) and I wouldn't want to be letting the cold air in by keeping the entire door open.

Edit: Also, even if not cold, insects.

Those are great for heavy loads but require pretty decent size holes, which can be difficult in old plaster walls. I have plaster and wood lathe construction walls and have had good luck pre-drilling with a 3/16 masonry bit on high speed with no hammer action, then using a course thread wood screw. If I don’t hit lathe going straight in I angle the screw a bit so I do.

All fair suggestions, thanks guys!

I think I'm just going to bite the bullet and buy another 16mm masonry drill bit that DOES fit a 10mm chuck.

I'm aware using a cordless hammer drill is gonna take a while, but for just two holes a new bit seems better than buying a new rotary drill!

Yeah. I think it usually takes a 1.25" hole to pass 3-prong US cord plugs through.