Hex Nut LED Flashlight




For several years I have been planning on doing this project, but it wasn't until now that I actually tried it. My plan was to make a miniature LED flashlight out of hex nuts, using them as the casing. I would use a matching screw as the cap for the battery compartment, and add a keychain to make it easy to carry around. 
Here's how I did it.

Step 1: Supplies

Things I used:
  • Soldering iron and solder
  • Third hand
  • Electrical tape (heat shrink tubing would be much more effective)
  • Clamps
  • Needle-nose pliers
  • Two part epoxy
  • Super glue (Krazy glue would be better)
  • Heavy duty scissors
  • Scissors
  • 6 18mm nuts
  • 18mm bolt
  • 20mm nut
  • Washers
  • White 5mm LED
  • Tactile switch
  • Switch cap
  • Wire
  • Ring for keyring (I don't actually know what that is, I just found it in my junk box)
  • Small spring
  • Positive terminal plate
  • 3 1.5V button cells

Step 2: Modifying the Parts

The first part to making the flashlight was modifying the nuts and the screw.
For the nut with the switch, I drilled out  a hole that would be big enough for the switch and the cap.
For the battery compartment I also had to drill out the nuts, because even though the cells would have fit inside, I couldn't fit in the insulation. 

Step 3: Button

To attach the switch to the nut I used super glue to glue it in. If you do this, be careful that you don't get any glue on the button itself, or you won't be able to press it in anymore. 
Then I attached a wire to one lead of the switch, which would go to the positive battery terminal.
To make sure that the switch stays, in place, I jammed in a small piece of cork (wood or plastic would work just as well).

Step 4: Battery Holder

To the white wire connected to the switch I attached the positive battery connector. I made a small hole in the side of the connector to let the negative connector wire through (next step).
To insulate the battery compartment I rolled up a small piece of paper pushed it inside the drilled out nuts.
I glued a piece of paper (insulation) to the sawed off end of the screw and glued a small spring on top of that.

Step 5: Glueing It Together

I used two-part epoxy to glue all the parts together, but the most effective way to do it would be with silver solder. To let the glue set I clamped the parts together.
For the smaller parts of the flashlight (like the switch, the spring, etc) I used Scotch Super Glue, just because it's much easier to use it on very small surfaces, for details. Epoxy is much stronger, though, so use it whenever you can.

Step 6: LED

If you're good at soldering and you have a good iron this step won't be a problem. But I have neither, so this step was pretty hard. I was planning on making the LED much shorter than this, but it was hard enough at this length. Make sure that your legs are the wight way around (the longer one goes to the positive wire and the short one to the negative).
To insulate the two legs I used electrical tape. Not a very good choice, but I didn't have any heat shrink tubing.
When you get the LED to work you can glue on the rest of the nuts. To finish it off I added some washers at the front. The washers also hold the LED in place.

Step 7: Done

That's it! There's your nut flashlight. 
Even though it works, mines had a loose connection. Here are some potential improvements:
  • Silver solder the nuts together: This will allow electricity to pass through the wall (nuts) of the flashlight, and will make the whole thing much more durable. That way you won't need to worry about the positive wire (the red one) getting entangled in the spring, and will create a much cleaner finish.
  • Use heat-shrink tubing instead of electrical tape: My best guess is that the insulation of the LED is what causes the loose connection. Heat-shrink tubing would make it much cleaner and would probably eliminate any short circuits.
  • Use bigger Nuts: Bigger nuts would make everything much easier to work with, and you wouldn't have to drill them out for the button cells to fit inside.
Post a picture of your own hex nut flashlight in the comments!



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    26 Discussions


    3 years ago

    Neat idea! You might be able to use something like this hollow threaded rod to make it stronger, and just screw the nuts onto it. It may make the diameter larger though. " am not sure the minimum diameter that the parts could fit into.

    1 reply

    Reply 3 years ago

    Thanks! Yeah, that was an idea but I couldn't do it without a drill press, so I had to settle for this. With a hollowed out thread you would however need to construct the entire interior separately and then insert it as one piece, obviously making sure that it's the perfect diameter so it slides in but there isn't too much play that could lead to loose connections. Basically it would be a lot more professional but consequently require more skill.
    If I end up making a third flashlight I'll try that. An M18 or M20 thread that would allow for a 15mm drilling and nuts with minimal outer diameter to minimize the overall mass (or possible aluminium? Or even titanium?), a powerful LED that uses the casing of the flashlight as its heatsink, and a 4.5V AA size Li battery as the power source.
    If you were to use a hollowed out thread instead of nuts, you might not actually waste all that much volume, considering the nuts wasted space with their thread in the battery compartment. A battery in a hollowed thread would fit much more smoothly and with less play. Instead of a bolt as the battery lid you could use a round nut or something similar. Sorry for the long comment, I got carried away. Hope that helped though :)


    3 years ago on Introduction

    Hi you could use the insulation of thin wire also to insulate the led pins.


    5 years ago

    I think i will make that too


    5 years ago on Introduction

    If I had time, this would be my next project! Very good job presenting it!
    Thanks for posting it!


    6 years ago on Step 6

    great idea!! It looks really cool. The improvements will make it 100% better.

    You do pretty good instructables which is just as much of a talent as the project itself. The diagram you added was a nice touch.

    keep 'em coming !!!


    Reply 6 years ago on Introduction

    Nah, that would be too soft and wouldn't seem as heavy-duty. I prefer the steel, even if it is heavier. And it's not that easy to find aluminium hardware.


    6 years ago on Introduction

    Truly amazing! Is it too heavy to put it in your pocket and take it with you on the key chain?

    1 reply

    Reply 6 years ago on Introduction

    I don't keep it on a keychain because I don't quite trust the epoxy. But if you're confident that it won't fall apart as it's swinging and knocking around, I guess it would be fine.


    Reply 6 years ago on Introduction

    Yeah, I know the weight is an issue, but somehow it makes it seem more heavy-duty.

    Chill Pillsjroth

    Reply 6 years ago on Introduction

    I agree, a little weight on an object makes it seem more high quality and less cheap and flimsy.


    6 years ago on Introduction

    How about adding a superflux or even a power LED rather than the puny 5mm ones?
    With the whole metal casing, you'll have decent heatsinking even for a luxeon star. Very nice idea tough. Looks tough and IS tough!


    6 years ago on Introduction

    A fun and safe thing to use in the plumbing trade. I often break down plastic lanterns, when to put it together with tools.