If you've seen my previous featured instructable, you know that I like to make bright LED lights that are helmet mountable. I thought my last one was pretty good, and at the time it was the best helmet mounted bike/ski light I could get for the money and effort. Well, it just so happens that a few months ago I was browsing the many different wares at my local Costco when I discovered much to my horror a bubble wrap package that contained, for the insanely low price of $29.99, three 200 lumen flashlights that are not only brighter than the one I made but also more weatherproof, shock resistent, and reliable than anything I can build. Realizing I was beaten, I bought the three flashlights and a big ol' stack of AAA batteries and went home to find a new hobby. I paused to look for a helmet mount for one of these things before gathering my tools and workbench into a giant garbage bag and heading to the knitting store for some yarn and crochet hooks.
Boy was I pleased to find that there was still a use for my craftiness after all! I found a lot of DIY solutions utilizing velcro that didn't look particularly stable or adjustable. I saw some 'universal' mounts out there that looked flimsy and dubious just from the pictures. Nobody had anything that utilized the O-ring trick, which surprises me considering that so many biking accessories (from lights to speedometers, what have you) have gone the O-ring route, because it just makes so much sense. Overall, it didn't look like anyone was really trying all that hard to make this work. It seems there just isn't any incentive for bike light manufacturers to build and sell a cheap accessory that would essentially render their entire high end, higher margin product line of over priced bike lights obsolete. Go figure!!!
"Well then," I thought, "Maybe I'll just postpone burning my workbench and tools in one giant pile next to the duck pond for another day or so and see if I can come up with a solution that will make me look at least as brilliant and innovative as I looked in the last instructable."
So I got to working, and re-using the O-ring mounted base I created for my last light, I came up with an adjustable mount for one of these venerable, screaming good deal, bright lights. I think that, combined with a good 900 lumen bar mount light, this should brighten even the darkest trails when I want to do some after work biking or skiing in the dark depths of Winter.
The big advantage this approach has over just about any other mount I've found for any sort of light is the big wing nuts that operate the tilt mechanism. Most light mounts have some claptrap with a screw and some sort of nylock nut or similar device that is always either too loose or too tight when you're covered in mud, it's snowing, and your flat blade screwdriver is on your Leatherman which is currently in the top of your pack which you would have to take off in order to retrieve. Why should you have to be getting out a tool to adjust your headlamp anyway? And shouldn't the tilt be something you can adjust quickly and the lock into place? Also, everyone knows that tiny screws and nuts are intrinsically predisposed to work themselves out of place and onto the ground only in the dark and only over rock slides and gravel piles. So why not go with a design that's a little less stupid? The mechanism I have devised can be easily adjusted even with the most be-gloved or be-mittened hands.
Step 1: Get a Rough Idea of Your Dimensions....
The first thing you'll want to do before bending, drilling, or soldering anything is to get a rough idea of where bends are going to need to happen. I did this the same way I did it in my last Instructable, by using cardboard from a cereal box.
I like to use brass to make things, because brass is easy to solder, easy to machine, easy to bend, and relatively strong and durable with a high fatigue life, meaning there's a lot of room to screw things up and make extra bends. That being said, you should always do a dry run with a piece of cardboard first, just so you don't end up with an ugly, wrinkled mess by the time you're done putting things together.
So, figure out approximately where things need to bend in order to wrap around the flash light you're working with. Perhaps the most crucial part is to remember to make the loop going around the flashlight slightly smaller than the actual circumference, because you'll want some room to tighten things down. Rough everything out, including where the screw holes will go.
If I were doing this again, I would have used just one bigger screw instead of the two little #8 screws. This is because as you tighten one, the other loosens and it's nearly impossible to get it right. Also, as is evident in the final product, there isn't a good way to get a screw driver to the screw once they're in, so I would probably want to solder in the screws and not the nuts, and find some way to use a wingnut for this part of the mount as well. Alas, I was in no mood to leave the apartment and go to the hardware store, so I just used what was lying around in my parts bin. So this is a somewhat imperfect solution, like so many things I do.
Once the cardboard looks like it's an approximation of something that maybe, just maybe, could work as some sort of mount, proceed to mark all the sharp bends with a sharpie (tee hee) and then transfer that with the utmost precision to your piece of metal.
Step 2: Bend It, Drill Holes, Make Sure It Fits
Okay, clamp that flashlight in the vice (lightly) and start bending the brass strip around it. I hope you didn't use a piece that was too thick, because that would make this part a real pain in the butt. Bend everything approximately to the dimensions you need, make the sharp bends that will create the "mounting wings" and the little niches where the tightening screw(s) will go and then drill your holes. Look through the image descriptions for tips on drilling the holes. It's impractical and time consuming to try to figure out ahead of time where to drill holes and make bends, so this is going to be a somewhat imprecise process. If you're really persnickety, you can try doing all of this in sketchup or some other CAD program first. But if you're going to go through all that trouble, you probably already have a 3D printer and should find some way to use that to make a plastic piece that does the same thing.
Step 3: Solder the Nuts in Place, You Can Be Done If You're Lazy
I decided not to do another soldering tutorial, partly because if I were doing this again, I would solder in the bolts instead, and I would use one bigger bolt and find some way to accommodate a wing nut. Now, if you just want to mount the light without being able to adjust the tilt, then you're done! Read on if you want to see how I made it so that the tilt is adjustable using the bottom piece I made for my other helmet light.
Step 4: Bend the "Wings" and Solder in Some Studs
It just so happened that when I built my last helmet light, I bought two extra brass screws. This meant that I could modify my previous mounting scheme that allows for a tilt mechanism to work with this collar mount. Just bend the wings of the collar down as pictured, drill a hole, and solder in a screw on each side to accommodate the other mounting scheme.
You'll want to use a torch for soldering, and lead free solder since you'll no doubt be touching this part of the project a lot. The best way I can explain the soldering process is to show this video:
Keep in mind that the dominant idea here is to heat up the brass first and use it to melt the solder. Also, understand that solder flows in the direction the heat is coming from, so try to keep the flame opposite the solder.
Step 5: Now You're Done.
Just slide the studs into the other mount, screw on the wing nuts, and you're done! The collar clamps down tight. This light isn't going anywhere. The other nice feature of this is that the batteries can be changed without removing it from the mount, since they unscrew from the back. Just bring a pocketful of AAA batteries, as I wouldn't trust this light to last as long as the bubble wrap it came in claims it lasts. I'll repeat what I said earlier: There is no way I can make a light this bright, this weatherproof and shock resistant, for anywhere near this cheap. Just go online and start pricing drivers, led's, lenses, and then try to figure out how to put the thing in a case and you'll be looking for a way to just mount one of these things on your helmet and be done with it!