After seeing a recent post about home made mirror mounts, I was inspired to do a write up on my headlight mount. I have a couple of short wheelbase recumbents and have built a variety of headlight mounts over the years. I've not been happy with commercial mounts I've seen because they don't hold the headlight far enough forward to keep my shoes from being illuminated, and from casting large moving shadows while I pedal. I prefer my headlight to be far enough forward that it's not distracting while riding. Historically my mounts required welding, and sometimes machining or special parts. I had a similar mount in mind for the Tour, but wanted to ride at night before I had the time to create my intended mount. So, I made a tempory mount that turned out better than I had expected, and I've decided to keep it on the trike. The nice thing about the temporary mount is that it's easy to build and only requires simple hand tools.
More images can be found at http://robpur.net/trike/headlight/
The mount consists of a bent length of 1 inch by 1/8 inch aluminum bar that can be purchased at many hardware stores, two StrapLock mounts, and a pair of longer than stock screws for the StrapLocks. The headlight is from MagicShine, with a Marwi mount.
I threw this mount together with parts that I had laying around, just to use until I made a "better" mount. But it has worked so well that I've given up plans to replace it. I bought the StrapLock mounts years ago (maybe even 10 years) from TurboCat Lighting Systems. I just checked their website and they are still available for $12 each. The bolts that came with the StrapLocks weren't long enough to go through the 1/8 inch aluminum, so I had to pop down to the hardware store to get longer ones. Making the mount is just a matter of bending the aluminum and drilling some holes. The cheap aluminum I used bends pretty easy. I clamped it to a table and bent it down with the palm of my hand. A bench vise could be used to hold it while bending as well.
I bought the MagicShine headlight from China a couple of years ago, but copies are now available on Amazon for even less than I paid buying offshore. I bought a copy recently from Amazon that carries the TSSS brand for around $33 with battery and charger, and it's brighter than my MagicShine. The battery in the photo is from my Amazon purchase.The problem with this kind of light is that the mount is designed for handle bars, and even on a round bar it doesn't work well. I found a guy that makes a custom adapter for MagicShine (and compatible) lights that allows the use of a Marwi mount. The custom part is cheap at $4.80 for both the adapter and a Nylon bolt. The mounts aren't bad either. A handlebar mount like I used is $9.85, and a helmet mount is $5.25. I have another light on my helmet. The site is hoffmanamps.com. Parts can be found in their web store in the "Bike Lighting Parts" section. I took the top off of a handle bar mount and attached it to the aluminum bar with a screw and Nyloc nut. The width of the mount matches the width of the aluminum bar nicely.
I made the mount a bit too long at first, knowing that I would likely cut it down later. The result was that it bounced around like crazy on my first ride due to flex in the aluminum. I attached the light to the mount with a rubber band, took it out at night, and then took my time playing with the light position, moving it back to make the mount as short as possible without casting annoying shadows. Then I chopped off the excess length and bolted the light down. After shortening there's only a small amount of detectable bounce in the beam. I can see the light shaking a bit, but only if I'm really looking for it. I suppose that if I was starting from scratch to build another mount, then I would consider using thicker aluminum. One other change that I would make is that I would leave a bit more overhang at the top so I could round the corners of the aluminum bar to give it a more finished look. In time I'll powder coat it black when I have other stuff to go to the powder coater.
The mount as I built it will not fit if you have a front derailleur, but it could likely be adapted by using longer StrapLock bolts and aluminum spacers so the aluminum bar clears the derailleur clamp.