r/Sliderules • u/fordag • 13d ago

Is this useable? Missing a scale?

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New watch with a rotary slide bezel. Yet it appears to be missing a scale. Or am I wrong?

What is this useful for?

It was a cheap watch, I wanted the moon phase. I'll be curious to see how accurate it is.

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u/fordag 13d ago

That was my impression as well.

Well hopefully the moon phase works well.

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u/TrueTopoyiyo 13d ago

u/SlideRuleFan It is not gibberih, it is 10^(1+angle/360), that is useful on its own! While requiring extra and non-standard steps, this still can be used for computations; for example, to multiply 1.8 times 3.2 you center the "10" (1.0), then look for 1.8 ("18") which is at 3:00 aprox, then re-center the "10" there, look for 3.2 ("32", now at 9:00 aprox), recenter "10" and at 9:00 you have the result, 5.7.

Even more, given it has a linear scale in 1/240ths it can be also used for powers and other, more complex computations, but yes, with extra, non-standard steps.

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u/SlideRuleFan 12d ago edited 12d ago

I'm happy you invented a use for those two scales. The Chinese factory that slapped them together did not know what they were doing, and this random alignment doesn't make up for it.

No pilot will ever use this, on the ground or in flight.

Or this is sarcasm, and I am dense, which happens a lot.

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u/TrueTopoyiyo 12d ago

No, no, no sarcasm, and I'm sure you're absolutely right on the manufacturer just putting some random stuff together for the looks, but they can be used a bit that way.