Tuesday, June 21, 2005

Reverse threads in your daily life

Raise your hand if you've ever tightened your pedals or BB cups when you wanted to loosen them... If you didn't know and you SHOULD know this, one pedal and one BB cup is reverse threaded. Meaning Lefty tighty, righty loosey. Don't even quote me on this as I screw it up almost EVERY time I work on these parts, and I had a cheat sheet written down somewhere but lost it. I think it is the Right BB cup and the left Pedal. Like I said, DO NOT take my word for it.

But how often do you see reverse threads in regular life. Here is one that I totally was NOT expecting.

A toilet lever. The lock ring that holds the lever to the tank is reverse threaded. After thinking about it for a while it makes sense given the direction which you press the lever to flush. If it wasn't reverse threaded every press would work towards loosening the unit.

When removing the old lever I didn't know about the threading issue and totally stripped out the lock ring. The whole thing ring, and threads were all plastic and they ended up just shredding. had to hack saw it off. Got one with metal threads and lockring this time. But in a few years when I go to take it off how am I going to remember that it is reverse threaded?

Oh another one I came across recently. My friends Sears weed eater. To access the compartment that houses the string require unscrewing a bolt that is reverse threaded. Of course it is clearly labeled on the unit which way to unscrew to open it, but that didn't do a whole heck of lot of good for two real men who ended up spending 1/2hr trying to figure it out.



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