Magic Bolt

Hi Iam Adarsh and Iam a first year diploma(Electronic ) student.This was an attempt to make a simple self screwing bolt with minimum tools and effort. I first saw this device in a youtube video. It was realy amazing to watch the trick and it seems quite easy to make also.But making an exact copy was impossible without a metal lathe, so i made some changes and managed to make a working model.This thing works with the help of a mobile phone vibration motor. Iam not sure about the sciences behind it's working but the motor vibration some how move the nut in one direction until it screws or unscrews it self.Changing the polarity of the cell will also change the direction of the nut spinning.

8 mm Expansion Bolt(use pin type expansion bolts which has hole through it's centre )

20 mm Nut

3×8mm 3 volt Vibration motor

Lipo cell 3 Volt(451012)

Epoxy Glue

Super Glue

Mini Grinder

Soldering iron

First step is to cut the expanding side of the expansion bolt. Only threaded side is required to make this device this will also make it look mostly like a normal bolt. Use a dremel to cut the bolt. Next select a suitable nut to make the head of the bolt.A nut thats just big enough to to fit the battery is needed.Next step is to cover both sides of the nut using a metal piece. I used thin aluminum sheet since its easy to cut and shape. cut a small piece out of this aluminum and glue it on the bolt uing super glue then using dremel shape it into correct fit as in the above photo even after sanding, joints were visible so i used solder to fill the gaps. It was very hard to solder the pieces, using more solder flex helped the soldering process.Once all side are soldered excess lead is sanded down to make the sides flat and clean. It took couple of soldering and sanding to get the desired result. Bottom plate is not soldered since i need acess to the battery for recharging.bottom panel is held in place using only super glue only. A small hole is drilled in the bottom plate to pass the motor wires.

Next step is to make a small switch that will be activated when it's close to a magnet. There are special switches called reed switch available for the same purpose but i was not able to find a small one that could fit inside the bolt head,so i made one myself to make this first you need a small plastic piece. I used plastic from medicine strip for this. Any type of plastic would work only thing to take care is the small magnet using for this trick should be able to move it down and it should spring back to its orginal place once the magnet is removed. So cut a small plastic piece bend it from the centre to make a V shape.It should keep this shape for the switch to work two small copper pieces are used as the contact plates. Thin wires are soldered on both pieces. and for the magnet to make the attract the contact plate a small nut(any magnetic metal piece would work)is glued on top of it as in the photo.check this switch with a magnet and multimeter to make sure it's working correctly. metal on top will get attracted to the magnet, which will move down make the two copper pieces in contact thus completing the circuit.here the most important part is the plastic piece it shuld be thin enough to move down with the magnetic force and strong enough to spring back to its orginal shape when the magnet is removed. Plastic from tablet cover or packing cover works the best. Or you can just skip the whole step and use a reed switch and hide it inside the body of the bolt this will be much easier to assemble. I tried mine with a reed switch but my magnet was not strong enough to activate the switch through the thick body of the bolt.

The magnetic Switch is then fixed inside the nut with epoxy glue once the glue is dried.Battery is placed above the switch and glued on place with some super glue.Check if the magnetic switch is working or not before moving on to the next step.wires from the switch is connected to the battery as shown in figure, the battery and switch must be completely inside the nut other wise it will be impossible to close the bottom side.

Next step was to fix the motor inside the body of expansion bolt.and the motor used here is a cell phone vibrator motor it came with a rubber outer protection layer which i removed and then soldered two wires on its leads, The motor is placed in the bottom side of the bolt as in picture. Make sure the rotating weight on the motor is not touching the body of the bolt.It was quite hard to glue the motor in place i used super glue with long thin nozzle to add the glue otherwise it will be impossible to add the glue, and a single drope of super glue can make the rotor stuck and ruin the build. Once the motor was Woking properly I added epoxy glue from the other side to make it more rigid and secure.then one wire from the moter is connected to the battery and other one to the switch as in picture. Then all exposed wire joints except the battery terminal are covered using epoxy glue to prevent short circuit.Battery terminals are left exposed to recharge the cell. I used a li ion charger to recharge the battery.Make sure it has a bms to prevent over charging. Once the battery is charged and every thing is working properly fix the remaining parts togather.the bottom panel of the bolt is soldered to the body of the bolt section. And the nut head is glued on using super glue.I didn't use solder to fix the bottom panel because i wanted to have access to the battery to recharge it.So when the battery is empty i can easily remove the super glued panel and recharge it.Clean the threaded section and the nut neatly any dust or glue will prevent the nut from spinning.make sure the nut is loose enough to move up and down smoothly.

finally to performe the trick hide a Neodymium magnet in a band aid and stick it on your thumb. When showing the trick just move it around the bolt head.When the magnet gets near the switch it will get activated and nut will start to move by itself, until it fall down. You can repeat this as long as the battery last. Once the battery drain's open the super glued bottom panel recharge it using a li-ion charger and glue it back on.and that's it The magic bolt is done!.

This one is not a perfect magic bolt it's just a proof of concept so there are some problems with it like some time the switch get stuck, battery drains fast, etc.

Sorry about my English I know its bad and I hope you understood what i said above.

Edit:videos shown above are played at 4× speed It normaly takes 1.5 to 2 minutes to complete unscrewing