First Real Aspheric Build

my L2 host measures around 7/8" and it's 1" long, that way i have room for my driver and can adjust the copper slug up and down to focus it in ect.....

once i get that position right ill then take my L2 host and drill a tiny hole for a set screw where the O-Ring goes to hold it into place :)

Yup, looks like 7/8" aluminum slug will be perfect.

Any thoughts on the LED to use?

An XRE will be best, an XPE next, XPG, and XML the worst for throw.

XR-E R2 EZ900 is the best match.

Well I received (5) aluminum 7/8" x 3/4" slugs, plus (2) copper ones from www.speedymetals.com (just a few towns over from me). I plan to go aluminum simply because the copper is so dang heavy (this is a lightweight AR build). Drivers are on their way (just 4 x 7135 from illumination supply), and hopefully the XR-E's as well.

Well I got my first prototype done (almost). I still need to grind down the bezel to fit flush.

I ended up using a random EZ900 XR-E that I had sitting around, mounted to a 7/8" x 3/4" aluminum heat sink, along with a 4 x AMC7135 driver so it's running close to 1.4 amps. The heat sink was then drilled and tapped, and the Solarforce L2m body was drilled and countersunk to fit a 3 mm hex bolt. This allows the focus to be adjusted, as there is no spacer in between the LED and the lens.

I'm using an Ahorton aspheric, but I have to say I'm a bit confused. I have some super cheap aspheric lenses from DX, and that was what I previously used for the light mounted on my rifle. Yet the Ahorton's shape results in a much larger projection of the die. I'm going for max throw here, so this is rather depressing.

On the left is the DX lens, on the right is the Ahorton.

I have XR-E R2's waiting to go now for the real build, and have some heat sinks on the way from Chicago X (which will be completely true and smooth, compared to my hacked up one above).

The ahorton lens will give you max throw, and since the back focal length is so short, a larger die image and a few more lumen to boot !

So even though the die is projected smaller on the DX-shaped lens, it won't throw as far as the Ahorton (all else being equal, such as quality of glass, etc.)?

ChicagoX is correct. The focal length affects spot size and not throw. The lens diameter affect throw. If both the Ahorton and DX are the same diameter they will throw the same distance.
The shorter focal length (Ahorton) is closer closer to the emitter and therefore results in a larger emitter image. You get a larger spot that throws the same distance as the smaller spot.
If you have a light meter you can verify that. The lux reading should be the same from the DX and Ahorton lenses.

Ok, so I assume the DX lens, because the back focal length is so far back, it's losing some of the light at the widest angles? This makes sense now :) Ok, sticking with the Ahorton.

Lens quality makes a lot, just check both yourself and decide which throws further, in real situations they do not always perform as you may think in the first place, I've got bigger lenses doing it worse than smaller ones and vice-versa.

Alright guys, hopefully you can answer this tonight before I complete my build. Using just an aluminum heatsink, should I run the XR-E R2 at 1.4 amps or remove a 7135 and run it at 1.05 amps? I don't mind if I cut the life of the LED, just as long as I won't kill it with moderate use.

I think you'll be fine if the led is well heatsinked and you hold the light in your hands.

I've a XR-E R2 2C Mag DD that draws 1.8A from a 18650. I have no problems as long as I hold the flashlight on my hand. If I let it ON standing on a table (candle mode) it's another story...

My UltraOK (Q5) draws 1.7-1.8A from battery without any special heatsinking (hollow pil in a MRV type body). I rarely have it on for more than 3min (although I do that daily), but someone else reported testing his for 15min on High with no problem.

EDIT: The above current values are from a DMM (20A range) with very low internal resistance. From another DMM (10A range) I get 1.4A from battery.

Run it at least at 1.4 amps. I would add a chip and run it at 1.7amps. A R2 XRE pulls 1.8amps when fed direct drive. I have been running one in a P-60 host at 1.8amps for a couple months with no damage.

Thanks guys! I'll just stick to 1.4 amps.

Bumping this thread from the dead. I want to freshen up my prototype host that is using an unknown bin XR-E. I bought an XR-E R2 to replace it, but decided to give the XP-E2 a shot. I want to push this thing hard, so I'm going to try my hand at reflowing directly to copper.

Now that I have my own lathe, I'll be able to create whatever heatsink I want. I want to get your opinions on this idea. I was thinking of buying copper rod, maybe 1/4". I'll machine the heatsink out of aluminum, then center drill a hole where the copper rod can be pressed in as well as soldered in leaving it so that the copper post is slightly raised above the aluminum heatsink. I'll sand down the contact points on the LED, reflow onto the copper post, then wire the LED.

Would this give me a good enough thermal transfer? I won't be as good as Match's reflow onto copper, but I wanted to make this as simple as possible.

nightcrawl’s method might be the “easiest” - similar idea to what you’re proposing, but the copper rod matches a hole in the star and ends up flush with the surface of the star. Some thermal paste under the star (might as well), then reflow the LED onto the star/rod. That way you get the benefit of direct thermal path with the ease of soldering wires to a star (have you seen how fricking small an XP-E is?!). Precision shouldn’t be a big issue if you’re using your lathe to drill the holes. Another plus is that replacing the emitter with something else in the future is just a short trip to the kitchen away :slight_smile:

Only potential hiccup? Finding the right drill size so that the copper rod is a tight interference fit, as you won’t be able to solder it in place. Heating the pill and cooling the rod before jamming them together might help.

But enough of this pansying around - where’s your first scratch built light :wink:

About 10 years out ;)

if you leave it that long, you might risk Chicago X’s machine spirit leaving the lathe, which would be no good at all.

Make yourself a couple of LED work lamps for the lathe - that’ll give you some great practice in turning and boring, plus it won’t matter if you screw it up. I’ve slowly been working up to making a couple, now that I have a better feel for turning. Boring is next on the list, although I’ll probably have to grind a tool to do it :slight_smile: I think anything like a torch or bike light housing looks intimidating, but there are plenty of intermediate steps to learn on along the way.