Aluminum bronze (954) and stainless steel (416) are unusual materials for flashlights. Both are expensive relative to aluminum, are much more difficult and time-consuming to machine, and tend to consume costly tool bits. So why use them at all? Aluminum is light, cheap, easy to machine and readily available. Titanium is light, at least. To cut right to the point, aluminum bronze and S/S are simply beautiful, especially in combination.
This project started out as a single body for an 18650 powering a nailbender SST-50 P60 module (6700K, 3 level DD, 3.6-6V). I figured that it made sense to make two at once, so one is offered as a host without a drop-in. The version with the recessed switch cap is the host. The price (conus) is $425 (SOLD)with the drop-in. (and $375 as a host - SOLD).
It ought to go without saying that the lenses are UCL and the switches are McClickys.
Here is what OnlineMetals.com has to say about aluminum bronze:
"Aluminum bronzes are most valued for their higher strength and corrosion resistance as compared to other bronze alloys. These alloys are tarnish-resistant and show low rates of corrosion in atmospheric conditions, low oxidation rates at high temperatures, and low reactivity with sulfurous compounds and other exhaust products of combustion. They are also resistant to corrosion in sea water."
The bodies started out as rough chunks of "cored bar" or pipe.
A lengthwise cut was made first to get a round piece to work with.
This allows the stock to spin true in the chuck so a concentric battery tube can be bored. Fortunately, the bore in the raw stock was just undersized for an 18650 so little additional boring was necessary. If it had been necessary to drill through solid bar to start my own bore, I might have gone looking for an easier project!
The bore was then opened up at the front end to fit a P60, as seen below in the finished product. I have tried several drop-ins from various sources and all fit. The relevant variable among P60s seems to be length at the front but minor variations are accommodated by the fact that the stainless bezel can screw in and out, that is, it isn't meant to seat against a flange.
The next step was to thread (28 tpi) the front end for the bezel. Aluminum bronze is funny stuff to work with. No matter what the combination of feed, speed, depth of cut and fluid, it protests with more or less scraping and squealing but somehow it all works out and very nice finishes can be obtained.
The process for making the bezels and tail caps was pretty much the same. Here, a piece of 1" stainless bar was chucked up to begin the tail caps.
A skim cut was done to provide a smooth surface for knurling.
A scissor knurler was clamped onto the stock.
The knurler was then fed lengthwise down the spinning stock, leaving a nice knurl.
I wanted a subtle rather than rough knurl so a very light cut was taken to leave a diamond pattern without the points - sometimes called a flat top knurl. The knurled section was then cut into two segments to yield blanks for the tail caps.
Each blank was center drilled, bored and then further shaped into a tail cap.
While we're on the tail caps, here is a step along the way toward making the retaining rings that hold the switches in. A piece of 1" brass rod was threaded and bored. Then two disks were sliced off and further machined to the final configuration.
The point of the picture is really to show the color of brass, in case someone is tempted to think that aluminum bronze looks like brass. It doesn't. Brass is yellow and aluminum bronze is a luminous gold.
The 24 tpi threads on the insides of the tail caps were cut and then the rear ends of the bodies were turned down to the right diameter for matching threads.
This is where it starts to get fun. The body is roughed out and is starting to look like a flashlight. The rest of the work is decoration.
Fins were made on the head with a very narrow grooving tool.
The body grooves are slightly different between the two but the basic approach is the same. The point of grooving the bodies deeply is to retain adequate diameter so that the lights feel good in the hand, while taking out some weight. Although it is hard to see in the pictures, the grooves in the heads and bodies are done with full-round tool bits so that the bottoms of the grooves are radiused rather than flat.
Here are more a few more photos that show various details and views:
The final product is attractive, functional and rugged. These lights certainly weigh more than aluminum counterparts but my take on that is that they have a nice heft and a solid feel that speaks of quality and durability. Of course, you'll want to take something else when you go backpacking. :laughing:
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the Host.
