I was told by an expert machinist that a tap and die set is cheap. We used to have a big set around here, but it’s AWOL. Might be worth a shot?
Rufusbduck cut the threads off the tail piece of a AAA MiniMag, rebuilt the tail end with nothing more than a thin copper disc showing on my BBC 261L. He has the original rubber gasket, a nice spring and the original threads, with that copper all that is showing on the outside. Slimmed it down considerably, did it with no more tools than you have.
Oh... like this?
Yowza! Chop! Yeah, like that. Smaller and smaller all the time, the case of the incredible shrinking pocket rocket.
Nice work guys. The thread should be renamed watch what we can create with very little. Love it. 
Now that is sweet right there! Nice job comfy!
Ugh, hipster LEDs! |(
Time for a high cri version?
That would be the perfect EDC.
Speaking of LEDs, I completely left out details of what's in the TR-801. 8x 350mA driver + 4x 380mA, the best of my cells can only get about 4.15A out of it. LEDs are 1A tint (6500-7000k), which are about the nicest cool white there is. Much less blue/green weirdness than what you get with XML2s of the same claimed color temp. The S3 is 2.8A and 2B (5700-6100k).
edit: Overall length is 3.80", or 96.5mm. Would be 95mm if I can ditch the glass lens next time around. Also, the front half of the pill can be shortened at the expense of reducing the internal height of the driver compartment. There's a good bit of dead space in there still.
How exactly does the cut-down tailcap work? I dont quite get it. :D
Looking really good, I still wonder why no manufacturer builds a small, thin light with a 3up in it.
I wonder if there is a prettier host that can be modded like that (without lathe)..
Screw it all the way down to turn on, back it off ~1/4 turn and it works in momentary mode, back it off 1/2-3/4 turn and it's completely locked out.
The first attempt I tried it with the spring soldered directly to the tailcap, but while the threads are anodized it's not as well anodized as it would have to be to work like that. So I had to start over and machine a pocket in the tailcap for the jumpered 20mm switch PCB. The clear plastic isolates the contacts from the tailcap, so the threads no longer play a part in making the connection, it's just the PCB bridging the cell to the tube when screwed down.
Nice idea. Thanks for the pictures. :)
Clever way to handle that. Nice little powerhouse you have as a result. 
Just got my triple on order along with the carlco 10507 and a convoy s4 host. Plan on DD for now.
Looking forward to this build. I have a couple of cool ideas for it.
Now the big wait begins.
Oof, S4 will be tough with those open slots in the head.
Finned heatsink!
Well... it still has to be sealed somehow. The stock reflector has an o-ring in the front face that seals against the lens, and another around the base that seals to the ID of the head above the pill threads. In the pic above you can see the 3XP board sits in the opening, so the area to the front between the board & TIR would be open, and also the area behind the board down to the pill threads. The ID of the head is very nearly exactly the same size as the 3XP board and TIR, so you can't do something like glue in a sleeve to cover the vent slots, the ID would be reduced too much for the parts to fit inside.
These Noctigon Triples are really cool! My first triples and I’m loving em! Today I made a light engine for a AA MiniMag that Texas Lumens chopped for me. This little bright red single cell beauty will be churning some 1050 lumens from an Efest IMR14500 in direct drive on 3 XP-G2 R5 2D emitters. Out of the light I tested it at 2.85A from a cell that hasn’t been charged in a month or two. I think it was at 4.12V.
All I had to work with was a 1” 6061 Aluminum bar, so I went to work on it and created this , sized for a QLite but hosting a contact plate for direct drive til my drivers arrive…
Very nice DBC. You continue to amaze me.
Awesome, a lot can be done at home if you have a place to work at.
Why not more lights with triples? Because Chinese did not copy the small Carclo triple lens yet. They don’t even resell the original.
Removing tail switch yes shortens the light unfortunately I don’t find it handy to have a twisty at the tail.