twist head on, battery/batteries out the front, body max OD 20mm: 1x18650?

Hello,
I'm looking for a flashlight to mount inside my forward-facing bike handlebar (base bar).
I have an Xtar VP2 charger and experience building my own Maglite- and Surefire-compatible incans and LEDs, but all tail click or twist - so my experience is deep but narrow, and I don't follow the larger flashlight market.

I'm hoping for some suggestions from fellow flashaholics on the following:

Requirements:
Twist head, single mode is fine (and direct drive is fun)
Battery/batteries out the front
No tail switch to fail (since the body will be permanently mounted and inaccessible)
Body max OD 20mm
Body-to-head thread flange >22mm so the body cannot be lost into the cavity

Flexibility:
Incan or LED, and I even enjoy the challenge and simplicity of direct drive LED
Any energy source, primary or rechargeable: I have lights with CR123s, AAs, AAAs, 16650s, etc
Any platform, although all my parts are SF-compatible
Any reflector/TIR, although I'm partial to smooth D36s (as above)

Thanks CPF

Just a thought.....
If you want to put an 18mm cell in a 20mm body, you are looking at at body wall of less than 1mm, taking into account the airgap.
Your flashlight may be as robust as a cigar tube.
P

True, but many (most, even?) flashlights are thinner than 1mm at the threads, and the only one I've ever broken was a mere 0.2mm.

A few initial options I'm considering:

47s Mini Turbo MKIII
Body diameter: 0.8 inches (force fit)
Head diameter: 0.96 inches
But only 1xCR123A
High 300 lumens 60 min - too short

EagTac D25C2 Mini
Head Dia. 0.78 inches (20 mm)
Body Dia. 0.78 inches (20 mm) (better fit)
2xCR123A, should fit a 16650?

• Led lumen: 530
• ANSI FL-1 lumen: 379
• Runtime: 1.5 hours

Seems to be discontinued


Peak Logan

• Barrel Diameter: 0.78
• Head Diameter: 0.78

Best UI
2xAA body should fit a 16650?

I'd really prefer a turbo head to prevent the light sinking in too far.

Ideally, body should neck up to a larger (>22mm) diameter to prevent the body from being lost in the cavity and to provide a nice perpendicular bearing surface, as my FM 3xAA to C head body does.

Streamlight Task-Light 3AA LED looks like a nice, cheap host - if the batteries can be removed out the front. Anyone know?

Emitter stack height is also quite high at 5.86mm bare, and 7.5mm on the star. Closest I have is a nice XR-E at 4.4mm for the bare emitter.
If nothing else, I could just remove the resistor and try to run it direct drive on Eneloops.

fivemega said:

18XXX cells have diameter of about 18.5mm (some batteries even more) so barrel ID must be minimum of 18.7mm
So thickness of body will be about 0.65mm
How do you want to have threads on it and groove for oring?

Click to expand...

I agree.

An 18650 in a 20 mm OD tube is probably cutting it too close.