I used the checkering file to make the vertical lines on the head into square knurling. Didn’t look quite as elegant as before, but was much easier to grip and cycle the zoom.
Then I decided to file down the curved fluted portion in the body into a cylinder and then apply knurling. Unfortunately that didn’t work well. Without the fluted portion of the body, the light looked unbalanced, was less aesthetically pleasing, and less comfortable in the hand. Even worse, without the extra aluminum from that portion, there was too little metal left in the body to properly heatsink the light. It got burning hot within seconds right where the hand sits when holding it. And then the driver would start to malfunction and the light couldn’t be turned off without removing the tailcap.
This was all caused by the removal of the extra body material. It worked perfectly before I tried that. Looks like this body tube is toast. :weary:
My backup unmodded body tube is sitting in its Greased Lightning bath getting its anodizing removed . Tonight I’ll work on modding it so I can get this light fully working again. This time, I plan fewer mods to the tube:
I won’t remove the front set of heatsink fins. The extra metal should provide some more leeway for heatsinking. This means the flood mode will be a tiny bit less wide, but since I’m hoping to replace the lens with a shorter focal length fresnel, that problem should fix itself.
I won’t file the fluted portion of the body. It provides necessary thermal mass and just looks and feels better.
I won’t file off the back 2 mm of the body tube near the tailcap. This will let the cap fully lock down even when using protected 18650s.
I will attempt to mount the new sideswitch a little further forward. However, if all goes well with my lens replacement I’ll likely need to dismount it and move it even further forward later.
Here’s a picture of the old body (top) and new body (bottom). Note that on the old body, I’d filed away the curved portion of the body just below the button in preparation with the goal of using the checkering file to add knurling. Around this point I discovered that I’d filed away too much of the metal and the body was now too light to dissipate the heat generated from the LED. I decided not to waste further effort and aborted the effort unfinished. I then decided to get a quick bit of practice with the checkering file before discarding the tube. As such, the checkering here is nowhere close to polished or even.On the new body on the left you can see the portion of the heatsink I’d filed flat to make room for the switch, and the hole for the switch wire. Not visible in this picture is the flattened area between the hole and the heatsink fins to make room for an electrical contact under the sliding bezel.
Here’s a picture of the new body with kapton tape and tin strip. The strip links the hole on the body to the switch. The front two legs of the switch will be soldered to the wide flat area of the tin strip on top of the heatsink. The bottom 2 legs will be bent down and press-fit into small holes that will be drilled where the 2 black dots are in the center of the heatsink fins. When the pill is screwed in the switch wire will be inside the battery tube, not too far from the hole. I then use tweezers to fish it out of the hole and rest it on the tip of the tin strip, which angles down into the hole. I then use a small 6-watt battery powered soldering iron to solder the wire to the tin strip. Final step is to take a small file and quickly file down any excess solder so the join is flat and then apply a piece of Kapton tape over the hole.
Here’s a picture with the switch soldered on: I subsequently, inserted a piece of toothpick under the switch so it sits flat instead of being lifted up by the strip. On the first body, the switch was completely flat and used a small wire to connect it to the strip. I might go back to that method. It was a little more effort, but resulted in the switch being flatter on the light and meant slightly more pressure was required to activate the switch.
Here’s a picture of the light with the replacement body.
I used the checkering file to convert the ribbed grooves on the head into square knurling and to add a ring of square knurling at the back.
Unlike the previous body, this one retains all 5 heatsink fins. I also left the interior of the battery tube slightly longer so it can use protected cells. I made a new switch cover that is held on with 4 screws.
Wow, Firelight. This is a fricken serious mod. Really like the direction you are going with it. I wish I had to guts to attempt what you're doing here.
I finally received my fresnel lenses. The plan was to replace the stock long focal length aspheric lens with a shorter focal length fresnel. I could then shorten the front of the sliding bezel as it wouldn’t need to extend as far. And I could shorten the lens ring since it wouldn’t need to stick out as far to protect a protruding lens.
I filed down the edges of the fresnel and press-fitted it into the stock lens ring as a test. I’m still undecided if I want to try this mod.
With the stock lens:
Flood mode - totally uniform beam with no hotspot and very sharp edges typical of most aspheric zoomies. No rings around the beam and almost no light emitted outside the illuminated circle. Beam width: 89.5 degrees
Spot mode - razor sharp image of the die. Slight radial lines outside the image of the die caused by reflections off the inside of the shiny sliding bezel. Close up there’s also a visible image of the star.
With the fresnel (replacing the stock lens. Same position, no other modifications to the bezel)
Flood mode - totally uniform flood beam with soft edges. Outside of the beam there is one ring caused by reflections off the inside of the lens ring just ahead of the lens (I believe modifying the lens ring should eliminate this ring. Also, there is a small amount of pure flood presumably caused by reflections off the inside ridges of the lens. This results in the area outside of the floodbeam being very softly lit up. It’s dim compared to the spillbeam on a conventional flashlight, but is still much brighter than the almost total absence of illumination outside of the flood on a conventional aspheric. Beam angle of the main flood is 92 degrees. Beam angle of the soft flood is around 170 degrees.
Spot mode - fuzzy image of the die, with a soft corona around it. Definitely doesn’t throw as well as the stock lens, but without a lux meter I can’t tell by how much.
If I stick with the Fresnel the plan is to make the following additional mods:
File down the inside edge of the lens ring. This will let me mount the lens approximately 2mm higher in the ring.
File down the bottom threads of the lens ring, shaving off maybe 2mm of threads. Enough that the ring should still stay on, but won’t be quite as thick.
File down the top 1.5 mm off the front of the lens ring. The lens will be closer to the front of the light. Since the new lens doesn’t protrude as much, less protection should be needed.
Glue in the new lens. I haven’t tried using the stuff yet, but I received my Norland NOA 61 optical glue and a 365 nm UV light to cure it. Hopefully the stuff works. I might also want to consider gluing a conventional 20mm AR glass lens on top of the fresnel, to help protect the fresnel. Not sure it’s necessary though as PMMA plastic is pretty strong… even with the exposed ridges of the fresnel.
File down the top 4-5 mm of the knurled part of the sliding bezel. This part would be done only after the modification of the lens ring is complete. Would continue filing until focal length in spot mode is correct for the new lens.
The light is currently 97mm long. The above modifications would reduce that to maybe 92mm…. making it one of the shortest 18650 lights around. If I decide I don’t like it, I could go back to the old lens, but I’d need to use a different sliding bezel. I have one backup bezel, but I don’t like the texture I put on it as much. I could also spend another $8 and buy another of these lights for spare parts.
If after performing these mods I find I really like the fresnel and didn’t want to go back to the old lens, I could possibly move the switch forward 5mm, up to the edge of the new bezel.
Here’s a picture of the light with the alternate bezel I made. This bezel has a small knurled section, a smooth section, and a ribbed section. Personally, I like the fully knurled bezel better as it provides better grip, even if it doesn’t look quite as shiny.
Here’s a picture of the business end of the light with fresnel lens press-fitted into the stock lens ring. If I decide to stay with the fresnel lens I’ll make additional mods as described in my last post that should shorten the light about 5 mm.
I filed down the front of the lens ring a bit. This reduced the light to 96 mm in length. Now I’m trying to think of additional ways to shorten the light.
Additional places to shorten the light?
File down the inside of the lens ring, then I could remount the lens 2 mm higher. This would let me file of the bottom 2 mm of the lens ring - would shorten light by 2 mm.
File off a bit more of the tailcap - would shorten the light 1 mm
Check inside of the pill to see if pill can be shortened - might shorten light 1-2 mm.
So if I do all of the above, the shortest I can get this light to is maybe 91mm. And the bezel modifications are only practical if I use the fresnel instead of the aspheric. Getting any shorter than that would require extreme action… such as mounting the driver in a small compartment on the outside of the light next to the switch. That might shorten the light, but would probably make it bulkier and less comfortable for pocket carry.
I’m not sure how much the fresnel is reducing the throw in spot mode, but I wouldn’t be too surprised if its dropping from maybe 30k lux with the stock aspheric down to 15 or 20k. I should get a luxmeter so I can check.
Has anyone found a supplier of small fresnel lenses with large LPI (lines per inch)?
All the stock small fresnel lenses I could find have very small gaps between the ridges. This gives better resolution for imaging… but is worse in a flashlight as each ridge has a dead area where some light is lost. The ideal fresnel would have very large gaps between the lines and a short focal length.
I agree about large elements and short focal length, but I don’t know much about where to get them.
I don’t know if small segments have advantages or if they are just easier to make with modern methods. I think the best would be to wrap around the source, like a lighthouse lens. The center focal length could then be as long as there was room for, and it would still catch all the light, though it would not all focus to the central spot. That would be harder to make than a flat sheet but maybe no harder than a conventional lens.
That’s an interesting idea. And if it wrapped all the way around the lens and further down the bezel it might work somewhat like an LED Lenser lens. So you wouldn’t lose half the lumens swapping to spot mode. Would have to be custom made though and probably very expensive.
I found a supplier who can manufacture custom glass fresnel lenses, that in the pictures have much larger lines than the plastic ones. The glass would probably be ideal, but unfortunately I think that would be far too expensive.
I’ve ordered a different fresnel lens from another supplier. If all goes well, it should arrive next Wednesday. However, it’s made of the same stuff and also has lots of very finely spaced lines. I suspect it will be no better than the current fresnel. I like the smaller size I can get with the fresnel lens, but it’s probably not worth losing 1/3 of the throw just to shave 3mm off the length.
I’ve also got a lux meter coming. Should arrive today or Monday. The plan is to use the meter to measure the throw with each of the 3 lenses. Until then, I’m holding off on making any more permanent modifications to the light.
With the stock lens I measured 22k lux.
With the fresnel factory fresnel lens I measured 18k lux.
This was using a protected 18650 cell. Interestingly, swapping in a Samsung 25r INR cell didn’t seem to increase output at all, though the light got noticeably hotter faster.
At this point I’m leaning towards going with the fresnel. It gives less throw, but will allow a more compact light. With the stock lens I have to use the original umodified lens ring and the light is 97mm long. If I go with the fresnel, I should be able to get the light to around 91 or 92mm long.
I also kinda like that the fresnel lens has a much softer edge at the sides of the beam.
The current emitter is a dedomed XML2 T6 3C from Illumination Supply. When I dedomed it, I slid the dome off in one move with a toothpick after 8 hours of soaking in Coleman fuel. This worked fairly well. A very thin layer of the dome remained on top of the LED, but I decided to leave it as the tint is a very pleasant warm white with no hint of green.
I currently have an alternate emitter soaking. It’s a 6500k cool white XML2 U2 from Mouser. I think I’ll let this one soak for 24 hours in the hope the entire dome will fall off on its own.
I installed an alternate emitter today. Here’s the measurements at turn-on with a Zebralight 3100 mAh protected 18650:
XML2 T6 3C from Illumination Supply dedomed, but with a very thin layer of dome left on top of the emitter (I think this thin layer reduces the tint shift, but also reduces the throw):
with Fresnel Factory 21 mm Fresnel lens: 18k lux
with stock aspheric lens: 22k lux
XML2 U2 cool white 6500k from Mouser dedomed (XMLBWT-00-0000-0000U20E1). Phosphor completely bare. I scraped the thin layer off the top of the emitter.
with Fresnel Factory 21 mm Fresnel lens: 28k lux
with stock aspheric lens: 34k lux
The T6 3C has a very pleasant orangish warm-white tint with no hint of green. The 6500k cool white from Mouser is a greenish white… definitely a worse tint, but much more throw.
. Tonight I’ll work on modding it so I can get this light fully working again. This time, I plan fewer mods to the tube:
