Wooden Flashlight

Another one of my bright ideas

My father-in-law is the "flashlight guy" in the family. Despite already having...probably several dozen, he always gets and gives flashlights for Christmas, and it's always a laugh for everyone. As much as we might poke fun though, we all have flashlights when we need them largely because of him.

The idea popped into my head one day of making a wooden flashlight as a lathe project. I thought it would be a great gift for my father-in-law in honor of his flashlight enthusiasm. I started doing some research and working up a design, and I soon realized that it was going to be a little trickier than what I originally thought.

Aside from just figuring out a multitude of intricate design details, there were two main challenges to solve:

1. The Circuit

Most flashlights (all the metal ones), actually use the body of the flashlight (the part you hold onto) to close the electrical circuit that makes it work. Below is a highly accurate and very technical illustration that shows how these circuits work. The blue line is the electrical circuit.

So, what's the problem? Wood is not a conductor, so if I make the body of the flashlight out of wood (which is the whole point of the project), then I won't be able to use it to close the circuit. Alternatively, running a wire up through the middle to complete the circuit presented several other challenges and compromises I deemed unacceptable.

2. Keeping It Together

Almost all flashlights thread together. Whether it be at the back, middle, or front, two pieces unscrew (those metal threads make contact, keeping the electrical circuit intact), and you can access the batteries, etc. While wooden threads are a real thing (and are very cool), I don't yet have the tools to create them. The flashlight has to be able to come apart, so...I had to figure that out.

Full disclosure, I used a few pieces out of another flashlight to make the job easier. I used a spring, battery carriage, LED housing, and the lens. I mostly did this for cost, because buying these pieces separately can be surprisingly expensive.

I wanted something that felt a little more like furniture than a mechanical accessory. This design begs to sit up on the face of the light instead of being laid on its side. The pleasantly stout toggle switch sits proudly atop, waiting to be called into action, like a lighthouse waiting for a storm. Then, when in use, it's tucked out of the way in the back, and leaves the rest of the design unobstructed. No, it's not as convenient to turn the light on and off with one hand, but this isn't a tactical light. It's an art piece.

Here are the plans I worked up.

You can get a better sense of what's happening on the second page. The illustration below shows the electrical circuit in the design. Keep in mind the light is pulled apart in this illustration, so there's extra space between all the components. In reality, it's a very dense assembly, and there was very little room for dimensional error.

Where you see the letter A in the illustration, I used a copper metal film, which then makes contact with copper metal film at location B when the two pieces are slid together. This is where the circuit is completed back up to the LED housing.

Clearances were tight. In fact, when I originally turned the pieces, I didn't take into account the thickness of the copper film, and it was a lot of work to go back and account for that later, because the two pieces wouldn't slide together with the film in place.

I ended up using a simple coarse-thread screw to hold the two halves together, and that worked quite well.

Ok, I think that's enough jabbering. Let's see some pictures. As usual, I didn't take as many as I wish I had, and I don't have a picture of it completely assembled. Getting the project finished was exhausting, so I think I was just relieved to be done!

This was a challenging and rewarding project that I'm glad I was able to complete successfully. And it's a good thing; I mean, what would my father-in-law do without one more flashlight?