oh and the radius of the bend, of the base is around 150mm, i compared it to a 1 foot diameter circle, curves match, but that isn’t critical dimension,
Maybe add a third loop/slit for optional over the top headbands? 
So… care to print this out and check? I’m sure I messed something up along the way, but it should make a decent first draft.
Re: a third-strap model… absolutely. Just after we get a working copy of the two-strap version.
wow, awesome. wish i had your skills, i will try to set up my printer tonight and test print it,
Thanks man. I got my first 3D printer (an Ender 3 Pro) back in July and have only dabbled in design since first getting it. But I like testing my skills and having a go on something functional is good practice for me. BTW, this was made in Fusion 360. Let me know how it goes!
It works!!! almost perfect, fits just right, sits firmly.
set up my cr10s last night that has been sitting for more than a year, and realized , i reinstalled windows, so my slicer is gone, installed cura 4.4, and realized i forgot pretty much everything, took me a while to figure basic settings, still did not figure most of them, thus you see stringing.
i used petg. to be honest that particular petg from e sun was always stringy before, but in any case holder works awesome, one thing thou, that tooth, that supposed work as a stop is too low, but grips hold the light so firm, it really is not necessary, but it was a bit longer, of entire light was deeper in, it would work, i guesstimate 1-1.5mm would be enough.(if too long it could always be filed down a bit) that is about the only change that could be done. i assume if printed from abs i’d need to adjust the scale in a slicer to compensate for shrinkage, like 0.5%?
,
in any case awesome job, THANK YOU. now pm me where to send that brand new d25, as i promised.
Woah, I can’t believe I got that close on my first try. Great job on those measurements! PETG should hold up ok with the heat, and hopefully should be pretty strong… I don’t have any PETG yet but I’m hoping to get a roll or two for Christmas.
I think I’ll bring the “rings” backwards ~1.25 mm (bringing the headlamp back towards the arc). Also, it looks like perhaps the rings could be moved apart about 0.5mm each? While I’m in there, any other minor tweaks you can think of?
I really do appreciate the offer, but I’ll pass. I just shipped my D25 to a BLF member for a song, and I’ve got a nice TH20 and a few Convoy H1’s. To make use of any more headlamps, I’d need to turn into Medusa 
you could move the rings apart too. seems like there is about .5mm room there, aa far as other tweaks, not really, maybe another version with wider base, for 35mm rubber band. if you feel like it, but otherwise this one is pretty much as good as it gets
i’m not sure i want to bother with abs, seeing how this one came out pretty good, petg supposed to be as strong and as heat resistant as abs, originally i wanted abs, but for first try i figured i do petg not to mes with acetone and stuff, but now i think i’ll abandon abs idea, maybe will get different petg, i heard esun isn’t the best brand out there.
Update (new files are at Thingiverse):
- Grips/rings moved 1.25mm rearwards (closer to the arc)
- Grips/rings moved 0.25mm further off center (so now a total of 38.5mm between them)
- A 3-strap version added
PS - do you mind if I add this picture to the Thingiverse posting so that people can get a real-world visual?
don’t mind at all, use it anywhere you want, it is your design
Wow, great job all! Now who can make a copper dual MCPCB? I'm in for at least two! 
i wonder it we can just use 2 16mm stars, reflectors will align and center them, it looks like they may just fit, but the reflectors aren’t that good, the beam is a donut, led is not in focus. i wonder if xp leds would focus better
I don’t have measurements on the MCPCB, but I have written down that the reflectors have a 15.9mm diameter, so it stands to reason that a 16mm MCPCB would fit. You could try two side-by-side, or if you want to go mule-style, just use some thermal adhesive and mount a single one in the middle with a clear window over top.
Possible. I'm using one of these on the bench running NarsilM - work'n pretty good. Like the ramping for a HL.
Here's a library of pics of the mod: Dual LED headlamp album
I use my 219B reflowed D10 with gChart RampingIOS and lit tailcap quite often, indoors now.
With a new optional strap I might get to use it more often outdoors as well.
version 2 is a success, stop connects with the light body just like it does on oem holder. awesome work, thanks again gchart.
Awesome, thanks for confirming!
Now D10-D20-25 have Fet+7135 driver and can run Anduril and Zebra like UI for 10 $
Very cool!
wow, this is very coll, i’d get several. where can i get them?