Left vs right thread 1

[Loco_]

Hello all,
My first thread on this forum.
Could someone explain to me when the left-hand thread is used? Till yesterday, I thought that when a shaft or pulley is rotating clockwise, the right thread is used because it is the direction of tightening, and this will prevent the bolt from coming loose. I saw this on some designs like bicycle pedals; on the left one, the thread is left, and on the right pedal, the thread is right-hand. But when I was rebuilding a car turbocharger, I noticed that a compressor turns clockwise and has a left thread nut. It's the opposite of what I was thinking. I am confused now, and for some of my designs, I need to be 100 % sure when to use the left thread.
Thanks in advance. Matthew.

 

[Denial]

Thanks for the correction, Prometheus. It was more than fifty years ago, and I have never touched an oxy-torch since then. A good thing I haven't, since I remembered it totally wrongly.

 

[Prometheus21]

Denial: I work in a company that design and manufacture such torches; albeit fewer and fewer these days due to cheaper products entering the market. Anyway I had the great pleasure and privilege to be taught by one of the original design engineers of such a product back in the day; he was at the time 88 years old (He retired at the ripe age of 94). So I got a hit of nostalgia when I read your post

 

[mfgenggear]

Thanks for the correction, Prometheus. It was more than fifty years ago, and I have never touched an oxy-torch since then. A good thing I haven't, since I remembered it totally wrongly.

No apology necessary. You probably forgot more than people know now.

 

[mfgenggear]

I was instructed on the job as an apprentice
If don't use it you lose it.
I was taught the safety rules dealing with oxygen tanks which is very explosive if contaminated with oil. It becomes a bomb.

And never lay filled tanks horizontally , it becomes a missile.

The pressure on oxygen should never be set above 10 psi. Becomes explosive if set to high.

Always open acetylene first. Light then adjust for
That blue flame.
Critique gentlemen.
And disclaimer Always follow manufactures procedures. With safety Always in mind.