HowTo: Modify Carclo Optics for XP-L Use--For $0.25

HowTo: Modify Carclo Optics for XP-L Use

Using a $0.25 T25 Torx Bit - Vinhnguyen54's Idea


Convoy S2+ Shorty (18350) With 3x Domed XP-Ls & Modified Carclo

1. Background

As many of you know, the Carclo 3UP & 4UP optics don't fit over the XP-L die since they were designed for the Nichia/XP-G2/XP-E2 class emitters. Our solution has been to either dedome the emitters, or try clumsily to use a drill bit or a sharp knife to open them up.

Last week I was over at Vinh's house (Vinhnguyen54) and as I was walking out the door, he asked me "are you still dedoming your XP-Ls?" I answered, "yeah, I am--I've tried opening up the optics and haven't found anything that I was that happy with", "check this out!" he said. He then proceeded to show me a very simple, cheap, and repeatable way to open up the base of the optics using a filed down T25 Torx bit. This was his idea, but I'd like to share it with all of you.

It is an imperfect method--but it is cheap, easy, and gives good enough results for me to recommend using it until something better comes along.


All lit up. Not too shabby!


2. Items Necessary

Here is a list of what you'll need:

  • T25 (or similar) Torx bit
    • A file to taper the bit
  • Slow electric screwdriver, or a manual screwdriver (fast is not good)
  • Carclo Optic
  • A bit of patience!

3. Filing the Bit
The bit's face needs to be slightly tapered--too little and you will have a hard time keeping it centered; too little and you will bottom out before open up the base enough.
You can file or grind the bit--it doesn't need to be perfect. You can see that my sample below is a rusty old bit, and that it isn't filed perfectly.


Just some rough file work will do.


Old, rough, and rusty, but it does the job!
4. Opening up the Optic
Open for business!
  • You want to use a slow speed when opening up the optic (I wouldn't recommend using a regular drill).
  • Stop frequently to clear the debris so they don't scratch the inside of the lens.
  • Stop frequently and check with an XP-L to see if you have gone deep enough.
  • The less material you remove, the less the beam is affected; however, if the fit is too snug you risk dedoming/ruining an LED.

That's about as deep as you want to go!
After you are satisfied with the depth, clean out all debris, install, and enjoy!
That's all!
Looks rough here, but don't worry, once installed and fired up it looks great!
5. Requisite Beamshot Discussion

I can't really see any extra artifacts in the beam, and once the optic is installed in the light, it looks pretty good. The dedomed emitters offer a bit tighter beam--more like the domed XP-G2--than the domed XP-Ls which offer more flood.
Not much to see here...except for bright floody goodness!

Or would it be beneficial to get a end mill bit? Like a 6 flute end mill maybe? Then it would cut clean... might be a centering issue then I don't know.

Thanks for sharing. You'll be sure to sell a lot more optics now! :bigsmile:

I'm sure that there is a cleaner, better way to do this, but it surely won't be $0.25! This is BLF, after all!

Thanks for sharing! Have you tried sanding and buffing the remaining burrs for a cleaner end result?

Have you compared light loss between dedomed emitters and dined emitters using this method?

I guess I am not a good member here, just ordered an 11/64" 3 flute ball nose end mill bit. :)

Dog ask me, cow should I know?

Edit: Ain't it purdy?

Regardless of the method, its nice that these can be opened up without changing the beam pattern. Thanks for posting.

But I'll use it for some of my other projects so it won't be for nothing either way. ;)

Cool. Thanks for the tip.

Thanks, that’s what I’ve been looking for. Any idea if the rough finish hurts the % of light much?

There is truly no way to know without having a perfectly polished one to compare it to. I'm sure it isn't optimal, but my 18350 powered S2+ measures over 2,000 OTF, so I'm pretty happy with it!

Thanks for posting!

I’m think it should be “too little and it will be hard to center” and “too much and you will bottom out” ?

cool idea!

ai laik!

Very cool. Nice to know it can be done without messing up the beam profile.

Acrylic edges can be flame polished, I don’t know if that can be done here.

is this really an advantage over a dedomed xp-l?

Massive advantage. Cereal_killer explains it perfectly here: triple XP-L project, need your input. Problem solved?

Keeping the domes on is most beneficial in maintaining tint. De-doming costs some lumens but most importantly it degrades the tint, sometimes in a way that is too much to take...the pea green hue.

Say you absolutely LOVE the 3D tint (I absolutely LOVE the 3D tint!), you really can't de-dome an emitter and wind up with that color of light. De-dome the 3D and it changes pretty drastically to orangish warm. The warmer tint emitters aren't as prone to show the pea green color, but they do shift away from the preferred tint. It's been pretty common with the XM-L2's to de-dome 1A tint emitters to keep the color as nice as possible. But are there 1A XP-L's? 2A, 2C, 3D...I haven't seen a 1A yet. The 2A's aren't horrible when de-domed, if you don't mind a slight off yellowish-green hue. (very slight usually, but still)

Thanks Richard! Like Dale, I LOVE the 3D tint, and now I can have it in a 20mm triple! Could you show a comparison beamshot between the modded dome-on triple and a de-domed one? And do you know the approximate OTF lumen difference?

Whichever way (this way or my way with a knife blade) the key factor to watch out for it to not bottom out the tool in the optic cup- if the in inverted dome get’s scratched it’ll screw up your beam badly.

My recommendation is to buy extra optic’s to practice with.