See how this 3D-printed gear turns clockwise no matter how it's cranked

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I remember making something like this out of lego maybe 15 years ago!


He is so impressed with himself!


So, basically, it’s a differential gear?

I dunno, it seems like it’s trivial to do this if you’re willing to tolerate ratchets. If it used only continuously-engaged gears, I’d be much more excited.

Also, I wish people wouldn’t use Fusion 360, even though if it were supplied by someone other than Autodesk I would admittedly be all over that.

That 507movements site is good though. It’s based on an old out-of-copyright book of which you can buy a cheap reprint.


Ratcheting mechanism only turns one way? You don’t say…


Okay, this one is a bit smarter…


Scanned from my copy of Cundy & Rollett ‘Mathematical Models’ (cost 30 shillings).

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I have a screwdriver that uses this mechanism so the bit will only turn one direction while you turn the handle in either direction. You have to hold a knurled center section for that action to work, though. Otherwise it just acts like a normal ratcheting screwdriver. It actually works pretty well.

Apparently it’s called a ‘double drive’ screwdriver. I’m seeing a lot of Kobalt ones, but mine is some off brand I’ve never seen before or since.

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caution: mac Cleaner ads (shudder) if you click it, you deserve it.

<3 for the use of “capricious”

I would like to attach this to a bucket or flag and watch people’s confusion as they raise it up, but then are unable to bring it back down.

Though it would be a pain to reset each time.

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