re: Dimming lights when I run power tools

Start with your extension cords for your tools, they may be too long or too weak. 18 g cords are just too small for most heavy tools but people buy on price and then buy them too long.

Next I would look at the circuits you are plugging in to. You may have too many in series sharing the breaker. I prefer to have a dedicated 20 amp breaker circuit on my bench just for tools.

Not sure of all the effects it may have but perhaps your ground is bad, check it at the breaker box, it will be a solid wire going down to the ground and attached to a rod that should be inserted 4-8' into the soil.