## A Real Sonic Screwdriver?

Well, there's a lot more going on than I can account for. And I really shouldn't be surprised.

I tested a bolt:
mass = 11.1 g
length = 30 mm

This bolt was designed to fit:
flanged metal nut 3 (numbered for previous experiment)
mass 6.9 g
thickness = 8 mm
outer diam = 18 mm
inner diam = 6 mm

As the reader will have observed, there are notable differences between the screw in the first experiment and the bolt in the second. These differences may account for the opposing observed differences in results. Or they may not. In my opinion, only further experiments will decide.
Apparently there in no strict definition that distinguishes a bolt from a screw. For myself, I've always thought of a screw as 'the mechanical pin that can be turned and tightened into place as a result of its thread with a screwdriver' and a bolt as 'the mechanical pin that can be turned and tightened into place as a result of its thread with a spanner or its analogue'. It's a personal, tacit definition, and I'll stick to it for the purposes of this exercise.

The bolt and nut are not a 'tight' fit which I would consider to be something like a screw in wood; but rather an 'close' fit. That is, the bolt and nut were machined for each other.
In this experiment, the nut was clamped between the two pieces of wood which in turn, was clamped in the vice. Also, the nut was clamped so that bolt was vertical. That is, clockwise rotation resulted in the bolt going down with gravity. Note that the head of the bolt is not the end of the bolt upon which the drill bit is acting on. It is hexagonal and so it is not possible to apply the drill bit and have the bolt rotate freely. No lubricant was used.
Perpendicular drill bit orientation resulted in bolt rotation but in a random way, with no overall discernible pattern.
Parallel drill bit orientation predominantly resulted in bolt rotation in the opposite direction. This is as one would expect: the drill bit was engaging the bolt as though it were a cog but not matching rotational speed like a true cog. However, the bolt would occasionally stop, and occasionally momentarily turn in the opposite direction.
Simply stopping I could explain by simply assuming that the bolt and nut frictional force at that time was greater than the resultant torque from the friction between the drill bit and bolt. But to turn the other way, even momentarily, means there is more than just a simple balance between frictional forces with a net result in torque.
I should add that I could not control these same direction of rotation events (SDORE). They were fleeting when the drill was rotating clockwise (so the bolt was going down with gravity) and were fleeting anticlockwise (so the bolt was going against gravity).
I tried different orientations and points of contact on the bolt. Some resulted in SDORE more frequently than others. Some resulted in no SDORE that I could see.

I could try a few more follow up experiments, but I strongly suspect I don't have the equipment, skill or knowledge to figure out what's really going on here.
Attached Thumbnails

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 Quote by qbit Simply stopping I could explain by simply assuming that the bolt and nut frictional force at that time was greater than the resultant torque from the friction between the drill bit and bolt. But to turn the other way, even momentarily, means there is more than just a simple balance between frictional forces with a net result in torque.
I really don't know anything about this stuff, but I'm wondering if you might be getting a 'reflection' of the vibrations coming back through the bolt from the clamped end. Sort of like an interference pattern?

 Quote by Danger I really don't know anything about this stuff, but I'm wondering if you might be getting a 'reflection' of the vibrations coming back through the bolt from the clamped end. Sort of like an interference pattern?
In the second experiment, there is no clamped end. Only the nut is clamped. It's not a great photo but you might be able to see this set up in the image in the previous post.
I think I follow what you're saying though. The only way I can think of explaining the results from the first experiment are in terms of interfering waves.
You've made a good point. Perhaps I should retry the experiment with the bolt head abutting the nut. In experiment 2, I forgot to state that the nut was mostly half way on the bolt.
I think I should also try to get an oversized nut to move along the bolt used in experiment 2 in the same way nuts moved along the the screw in experiment 1. There are a large number of physical differences between the screw and the bolt used.
Do you have any ideas on any other experiments I could do?

How did the link on the word 'friction' appear in my previous post? I didn't put it there.

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 Quote by qbit How did the link on the word 'friction' appear in my previous post? I didn't put it there.
The site software automatically links certain words to the dictionary.
I've gotta go to my pool match now, but I'll get back to you later.
 This just keeps getting weird. True, my rig would not like pass NATA accreditation, but I can't understand why I can't replicate the 'same direction of rotation events' I described in a previous post with the bolt in what I consider to be a very close replica of experiment 2. However, I tried the bolt from experiment 2 in a similar set up as experiment 1. That is, the bolt is horizontal and the drill bit applied parallel to the bolt. Let's call this experiment 3: I used: Metal bolt mass = 11.1 g length = 30 mm head diam = 12 mm thread diam = 8 mm thread lead = 1 mm flanged metal nut 4 mass 11.3 g thickness = 10 mm outer diam = 21 mm inner diam = 8 mm Previously, I had mistakenly listed this nut as having an inner diameter of 6 mm. I am relieved that PF is not a journal :) Anyway, parallel application of the bit resulted in the nut behaving just as I had described in experiment 1: rotating in the opposite direction to the drill bit and following the thread. Lovely to watch. Completely consistent with the first experiment. So, it was nice to know that despite the fact that two very different bolts (aka screws) were used, the same results were obtained. I probably should add that the bolt, (from experiment 2) appeared to me to be more sensitive to the drill bit. Backing off from the drill revs resulted in less erratic behaviour, less jumping and greater consistency. Now for the weird bit. Let's call this experiment 4. I put the close fitting nut used notably in experiment 2: flanged metal nut 3 mass 6.9 g thickness = 8 mm outer diam = 18 mm inner diam = 6 mm on the same horizontal bolt as in experiment 3 (above). It turns out that the direction and magnitude of rotation of this nut is highly sensitive to where I apply the drill bit to the bolt and despite the direction of rotation of the drill bit! In other words, I could get the nut to rotate in either direction depending on where I placed the drill bit on the bolt (at various points I've tried to indicate in the image. Note also, I've included the screw from experiment 1 for comparison). I could also get it to 'jiggle around' in a given position. I got the feeling I was playing a piano. It was a little frustrating that I could no longer predict how the system should work, but otherwise fun to play with. Any ideas how to map the vibrations or at the very least determine what frequency range they're in? I fear that without that kind of data, it would not be possible to put together a model of what's going on. This is a whole new level, yeah? I suppose it would make sense to do another experiment where the bolt is turned around in the vice so that it is the bolt head that the drill bit makes contact with. If a sonic screwdriver were ever possible, this is the end, I assume, it would have to deal with. Or would it preferentially deal with the material the bolt is embedded in? Perhaps waves travelling through both media need to be considered? Attached Thumbnails
 This question is fairly un-related to the doctor Who TV show since he doesn't use the screw driver to un-screw things, in season 3 of the new series "The Evolution Of The Daleks" we see he uses it to losen bolts and screws not to turn them. P.S Am i a Dr. Who Finatic???
 Hey guys been following this topic for a while now, some amazing results, yet been thinking I know we are looking at sonic waves here, but what about a powerful focused rotating electro magnet, wouldn't that theoretically be able to undo a screw ? and I would have thought something like that would be quite easy to build ? Craig
 Hi I am new so please tell me if I am out of line, But has any one considered if the effects change with alternating levels of heat, From say three lasers of deferent intensity's?, Plus in a real Sonic Screwdriver I think a number twist control may be smarter like the old combination bike chain lock, 001 turn screw clockwise, 327 fix wire, and 498 turn to next TV channel,
 Hey Brennshaw, I'm really interested in this whole Sonic Screwdriver concept and really wanna make one of my own. You wouldn't happen to have some pictures of the components that you described in your post about building a Sonic Screwdriver?

 Quote by Danger Please do. I don't expect that it will lead to anything marketable, or even tremendously practical, but it will be interesting and educational. Others might even have suggestions to improve your methods as you progress.
Don't be so sure. I used to work in a factory that used electronic component feeders. The components were dumped in a bin that vibrated. Around the inside of the bin was a helical ramp and the parts vibrated themselves up the ramp to the device that inserted them in the boards. The ramp went upwards in a clockwise direction. My guess is that the bin was vibrated with a sharp hit in the counterclockwise direction and a much softer return in the clockwise direction.

A screwdriver could be made using a similar principle. To tighten a screw, a rotary impeller could be hit hard in the clockwise direction with a spring return. The impeller would ratchet the screwdriver blade clockwise and ratchet itself in the opposite direction on the rebound. With the correct ratio of masses between the impeller and blade the screwdriver may exhibit no net torque. Such a screwdriver might have a use in space.
 So does anyone have any other ideas about how to construct a portable sonic device that could jiggle out screws or perhaps coax door locks open? One idea I have is that the sonic wave vibrations may be more effective if the emitter of the sonic device is in contact with the bolt/door lock, as it might be able to transmit the impulse of the waves through the mechanical apparatus more directly.
 Has anyone heard anything more from BrennanShaw? in any shape or form...and is what what stated possible? one last question...are all the items he stated easy to get hold of? Thanks!
 Is he bonkers??? He can't even spell correctly!!! And what in the world are charching cells???? Ok, can you give me an ingredient list to what brennanshaw just posted? English preferred please. Thanks in advance!!!!

 Quote by shockfish08 So does anyone have any other ideas about how to construct a portable sonic device that could jiggle out screws ...
The discussion here reminded me of the 'whimmy doodle'-- aka: the 'Gee Haw Whammy Diddle'; or the 'Magic Propeller'. A stick is rubbed on another stick with notches in it and with a 'propeller' at the end. The notched stick is held firmly in one hand and the other hand holds the stick that will do the rubbing. Depending on how the rubbing stick is held, it is possible to make the propeller spin in either direction. These two web sites are interesting--- Google will return many more.

http://www.sciencetoymaker.org/prop/index.html

http://en.wikipedia.org/wiki/Gee-haw_whammy_diddle
 The only way I can see this working is if you could construct a rotating sonic field, that could fit into the grooves that make up the screws head. It seems like such an indirect method. Wouldn't a device that could generate a field like that be so big that it would simply be easier to carry an actual screwdriver? Although this leads me in an interesting train of thought. Could pulsed sonic waves be used to warp the screw? Compress it, make it looser, and then remove it?
 HELLO. CAN ANYONE TELL ME HOW TO GET THE ITEMS LISTED BY BRENNANSHAW. I AM TRYING TO MAKE THIS BUT CANNOT FIND THE PARTS NEEDED. IF YOU CAN HELP ME PLEASE SEND THE INFORMATION TO ME @ PHYSICS FORUMS.THANKS IN ADVANCE.
 I think these Dr Who fanboys are smothering the scientific aspects of this study to become one step closer to becoming their loved hero. This aside, I beleive that is a sonic wave was emitted at the correct frequency, the screws shall indeed vibrate and in turn, rotate, thus, unlocking a door.... perhaps not by the traditional turning of a handle, but more taking it off the hindges. I wish anyone the best of luck when trying to make such a thing, and I look forwards to seeing the the results.