Tungsten Mule Flashlight

Tungsten is not usually associated with flashlights, mainly due to its density–it is almost as dense as gold, so any light will have some weight to it. However, Tungsten is also very hard, durable, beautiful and conducts heat much better than Titanium.

So, why not make a flashlight?

Start with a chunk of Tungsten–actually an alloy of 90% W and some nickel and iron:

Block of W

And a design idea–shown here as a rendering from a 3D CAD program:

WLight-3

Alas, the bar has a square profile, and lights are round, so time for some lathe work:

W_Mule_WIP-1

Inserted into a four-jaw chuck, the square bar can be turned down until it is round. Why start with a square bar?

Because it was the least expensive piece of Tungsten that I could find on EBay. :-)

W_Mule_WIP-2

And quite a while later, one end of the bar is now round. Then the other end:

W_Mule_WIP-3

That gets turned down to approximately the same diameter as the other end.

W_Mule_WIP-5

Then I drill into one end of the bar and bored it out to fit on an expandable collet. Once in place, the entire length of the bar is turned down to its final diameter. Next operation is to split the bar into two pieces, one will be the head of the light and the other is the battery tube. That operation is called parting off.

W_Mule_WIP-6

Alas, when working with new metals, I really don’t know exactly how they will react during all operations, and in this case, the parting off didn’t go smoothly. As you can see above, some chattering of the cutting tool was occurring, and had I continued, something bad would have happened.

So I changed tools and proceeded cautiously:

W_Mule_WIP-7

And, finally, the two bar was in two pieces.

W_Mule_WIP-8

Then the interiors of both pieces were bored to the correct diameters to accommodate the lens, light engine and battery.

W_Mule_WIP-9

Once again on an expandable collet, the head is being milled with 27 axial cuts.

W_Mule_WIP-14c

Since the design is for square, or close thereto, pyramids, circumferential cuts have to be milled to complete the squares.

W_Mule_WIP-15

And then the axials cuts–this will be the battery tube, which as you can see, is already threaded to mate with the head of the light.

W_Mule_WIP-16

And finally, both pieces are decorated and ready to be fit together.

W_Mule_WIP-17

A welcome sight, when the pieces are threaded together and they mate well.

W_Mule_WIP-19

Close-up of the square pyramids.

The rest of the work consisted of making a light engine, using a Nichia high CRI LED and a mini FLuPIC driver, which provides three levels of light output. Then it’s a matter of installing the O-rings, the lens, the LE and the battery to complete the light:

W_Mule_WIP-20

Completed light on high.

W_Mule_WIP-25

A quick beamshot showing the broad diffused output of the light as it has no reflector.

W_Mule_WIP-22

You can see that the LED is very close to the lens, giving the wide beam pattern. Also barely visible here is a Delrin cover used to hide the wires soldered to the metal core PCB that the LED is soldered to.

W_Mule_WIP-26

The light weighed 3.5 ounces, including the battery–hefty, but not that heavy. The squares were lightly buffed to make the light hand-friendly. The final diameter was 21mm and the length was 46mm.

This light was offered for sale via my Spec Build Opt-In Mailing List. If you would like to be added to the list, please contact me.

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