what’s that yellow paint for

It’s called a torque stripe. It tells you at a glance if the bolt has moved.

If it gets loose the paint won’t align. That’s could be a problem.

I'd like to know what that noise was after the one guy says "Pressure."

Threadlock

I got to do this up on a wind turbine. The builders straight up forgot to install a nut, and we were Commissioners. My partner and I used a briefcase Honda generator to power the most insane portable nut tightener I've ever seen.

Torque matks

It is used to detect if the nuts have become loose via a visual inspection. Similar to marking the timing chain on an engine.

To mark the bolt that it’s been torqued and as a visual reference if it moves or loosens up.

Why are they left-hand threads?

Let’s me ask my wife’s boyfriend brb

Every DIY guy seeing fasteners that can't go 'tick-tick-tick' on the garage floor and evaporate from existence.

Thread Sealant 🤔

Inspection

That is a torque multiplier, tightening that bottom nut, paint marker on nut and threads will indicate if it moves later on

I'm more interested in why those are reversed threads.

Nut has been torqued

Marking to make sure they don’t move in the future

visual reference when the nuts loosen