This screw is impossible


Originally published at:


did I miss something? Appears to be working the way any screw and nut works. If you spin the screw vs spin the nut, the direction it moves reverses for the direction of rotation.




I thought “the impossible screw” was that position they left out of the Kama Sutra.


Roger That!




Wait the first comment isn’t “That’s what she said”?

I am disappointed in all of you.

Also that is actually a neat little puzzle/trick.


“I’m screwing it in right now!”
“My nuts are tightening”
“Is this against the thread?”


A normal screw and nut can be turned in both directions just by turning the head of the screw. This one seizes up when the head is turned counterclockwise. The only way to get the head to turn counterclockwise is to turn the threads on the other side of the nut clockwise.


I see now - I had watched it with sound off and bailed after a 30 seconds of nothing.


“Not without a washer you aren’t!”


It’s a clever gizmo, but maybe not the most entertaining party trick ever.


I have such a NSFW mind.


Oh good, I’m not the only one!


Any screw is possible if you’re brave enough.


You have to have the nuts for it.


Possible but not very probable; mutual consent and mutual interest take precedence over all.


Yeah, this would be a really good present for certain sorts of people – you could just give it to them and they would have fun figuring out, first, why it’s less banal than it looks, and then, how it’s done.

The only problem is, as shown, the recipient would start by spinning the nut all the way off the bolt, and that would give away the trick. It only really works if you introduce them to it before handing it over, which is not how xmas works.

To make it a really great conversation piece you’d need some way to discourage folks from turning the bolt too far, so that they discovered the odd behavior before they figured out the trick.

ETA – thinking about it, maybe it’s not such a problem. Most people would pick it up and start turning the bolt from the head end, which would either move the nut up or not move at all, so as long as the split is hidden when the nut is tightened all the way, most people would discover the odd behavior before they worked out the trick.


I wasn’t aware my comment could be construed to have creepy undertones of forced sex. Thanks for letting me know!


John Scalzi has a very apt saying about when attempts to be clever fail.


Don’t make me link the Robot Chicken “Khaleesi” episode!