The Aspheric lens flashlight is something to behold. Laser like beam that has a reach which is unequal by any other flashlight.
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Just to set the record straight, no photo or beam shot does this flashlight justice, it’s better in the light! Everyone who has seen it; wants it.
Here is a materials list, should you wish to have a go:
- Skyray 7xT6 host (I would use a 9xT6 if there is one lying around as it looks better and has a bigger head which almost accommodates the 75 mm Aspheric lens)
- Cree XML2 U2 with 0D tint on copper Sinkpad
- Diameter 100 mm x 130 mm aluminium billet (given to a competent, retired machinist)
- 75 mm convex glass Aspheric lens
- Kaidomain 9A 3 mode driver
- Potting compound & Arctic Silver thermal paste
- Stainless steel hex head screws, M3 x 15
- Two good friends
- Lots of red wine (Preferably a well aged Merlot/Cab Sav)
The idea of this build flickered to life during our stay at the beach house where I was testing my much coveted STL-V2 (highly modded to add) and an off the shelf Archon D10U (a diving torch with a good 30mm glass aspheric lens). The V2 had a tighter and brighter hot spot, but the D10 was not far behind, with the bonus it illuminated a larger area (distance just <200m). The words my father kept on saying to me where sinking in: “A good lens is hard to beat.
So, with this new found misery of my coveted V2, I started Googling aspheric throwers and of course, they where out there. First thing I did, was purchase an aspheric lens from China ($15, so cheap but considered good quality none the less). Next step was a phone call to a friend and I was set up with a Skyray 7XT6 host, a call to another (both guys are very knowledgeable in this field) and I knew which LED to get and how the torch would take shape.
Note: some months passed as I waited for the parts to arrive, so please don’t get the impression this was a 10 min job.
Finally the aspheric lens and the components arrived. The first item on the cards was to de-dome the XML2 in petrol. This takes 24h or so (I did try to do it in less time and broke waiver wires while removing the remaining bits of dome left on the LED, so have patience). Time enough to mod the driver. The Kaidomain driver delivers to its promise of 9A, so it’s a must that 2 of the 6 sensing resistors be removed. Measured, it’s now delivering 6A to the XML2 (simple maths aint it :)). 
A little fidgety and some parts swop from the original driver saw the Kaidomain driver inserted and potted in the 7xT6 pill. Watch this space, there is a second interchangeable pill on my desk which is earmarked for SBT90R/SST90/CXA???? A very thin layer of good quality Arctic Silver thermal paste was used when placing the XML2 onto the pill. Don’t worry, there is so much thermal mass the single XML2 makes it warm, but never hot, even when running for extended periods. Forget those oven gloves. There is one thing I would change on this build – the XML2 is secured to the pill with Pratex Quickset Clear. Yes, I’m ashamed, but the driver was already potted in the pill and I did not then want to drill and tap the holes to bolt it down. The XML2 is not going anywhere, but there is a more refined solution. With the pill in place, an interim test was conducted and the results where astounding.
I was testing it in the street outside our house while the dogs next door were having their usual barking session (yes, they bark incessantly and even neighbors further down the road have laid complaints – so I don’t feel too sorry albeit the owners and not the dogs’ fault). I looked at the dogs and then looked at the torch, mmmm. Screw it. High beam and swung it over to shine in their direction from about 40m away. They both went yelping away!! I could not be believe it… They came back for more, and were sent yelping again and that was the last I saw of them for that night. This torch is goooood.
Purchasing a largish aluminium billet on a budget is not the easiest thing I found out. Eventually I found a company specialising in copper and aluminium and ended up paying around $20 for the piece.
With some hand drawings and the D10 as an example, I sought out a retired machinist with some very nice equipment in his garage and a good reputation. It was commissioned with one week’s wait. The part came back, functional and good workmanship, but not the look I was after. I showed the drawing the to the machinist and pointed out the differences between it and the part. His comment was that I should have provided with a CAD drawing if I wanted it done properly, so needless to say I’m not going back and will seek a new pasture for future work. A note to the builders out there, recess the aspheric lens for protection and makes it easy for the torch to stand on its head.
Assemble the torch, yay it works, now take it apart – send in for black anodising.
Re-assemble – enjoy. 
Those miserable little screws holding the aspheric lens in place had to go (those with eagles eyes I’m sure are jumping up and down by now) – stainless hex or nothing.
Some months after the final build we were out hunting and a friend who had driven 10 hours one way to join us for the weekend, did not see anything during the excursion. So with the farmer in tow (he had seen the torch and wanted to see it action)(I don’t advocate hunting at night, but there are exceptions to every rule) we went out to look for a Kudu. Needless to say, we were barely in the hunting camp when we were in luck! We spotted a young bull about 206.5 m (we had a laser range finder :)). Even in the pitch black you could count the 1.5 turns of the bull’s horns! A perfect shot to send him away happy for the 10 hour drive home the next day.
The torch was sent down to Cape Town to get some quality pics and beam shots. Pics of the torch, easy, beam shots, not so. The guy kept on complaining it was too bright! I agree. You can see the spot on the mountain 1 km away, but it’s very hard to capture.
If a pic could say a 1000 words, the one below would should be saying a whole lot more And you would think that was the last mod? Well its not. My waiven collar is in the post… Why? Because it can be better 
Watch this space, there is a 180 W (18 XMLs) light bar build underway with 30mm aspheric lenses from the same supplier who supplied the 75mm – promises to be epic!
Many thanks to Extreme Lights (extremelights.co.za) and Lothar on BLF for the good times during this build.
While posting, the first pics of a pre-production run became available… Teaser below. The host may look like the familiar 9xT6 of a reputable brand, yes, because it is. And the amazing feature is? You guessed it, a sliding focus head for easy adjustment between thrower and floor.
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