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Mid size LED flashlight.

Posted: Sun Dec 26, 2010 5:50 pm
by Bfinnigan
Machined from 2011 aircraft aluminum with a Lexan lens. The LED is a cut down SMJLED modified 4 die 5mm LED with 180 degree viewing angle It is rated at 15 lumens at 80ma drive current.
I used a 39 ohm 1/2 watt resistor in series to moderate the current. It uses two 3 vt lithium batteries and will run the LED for 40 hrs.

The flashlight is turned on by rotating the battery compartment cap clockwise. This is a very simplistic but durable switch set up and you would have to break the flashlight to damage it. To me simple means less parts to fail. The battery cap also has a slot I machined in for a lanyard.

The unit is 4 1/4" long and 1" in dia (1 1/8" head). It should stand up to a lot of abuse and last many years.

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I mega polished the parabolic reflector with diamond paste. Before attaching the lexan lens I pooled up some nitrogen to displace any moisture to prevent corrosion of the reflector.

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Re: Mid size LED flashlight.

Posted: Sun Dec 26, 2010 9:01 pm
by zelph
The LED is a cut down SMJLED modified 4 die 5mm LED with 180 degree viewing angle
How did you cut it/modify it?

40 hours life is excellent. Does it have an "o" ring to water proof it?
Are lithium batteries guaranteed leak proof? will battery acid corrode the aircraft aluminum?

Re: Mid size LED flashlight.

Posted: Mon Dec 27, 2010 1:20 am
by Bfinnigan
A cut down LED has a flat top instead of the usual dome. It projects more light forward then a dome top. The tolerances are so tight that it doesn't need a sealing ring. Most components that need a sealing ring have a little "slop" that would keep it from being air or water proof. I took my time on this and got it very tight. It's time consuming but I am never in a rush making things.

I have a head lamp that uses the same batteries and LED and it's rated for 100 hrs on low and 40 on high. My flashlight only has 39 ohms of resistance so it's always on high.

I never leave batteries in flash lights but i'm sure if they leaked there would be some corrosion. Aircraft aluminum somewhat resists normal air/water corrosion but not any harsh chemicals.

Re: Mid size LED flashlight.

Posted: Mon Dec 27, 2010 11:29 am
by zelph
I have one of those hard anodized aluminum flashlights that are black and take 4 "D" batteries. The batteries in it must have leaked and corroded the threads to a solid mass. The head and end cap are immovable. It is now a relic of the past. :roll:

Re: Mid size LED flashlight.

Posted: Mon Dec 27, 2010 11:49 am
by Bfinnigan
I have a 6 D cell MagLite that I carry in my SUV. It's about 25 years old and I have only changed the halogen bulb once so far. I spray the batteries with Permatex battery protectant and have never had any leaking problems. It's that purple spray you get in auto parts stores. That stuff also does a great job of keeping your car battery terminals clean.

I will also coat the inside of the new flash light with it also. Even 25 years ago I paid $80 for my MagLite. They were made in the US back then which is probably why it still works.

Re: Mid size LED flashlight.

Posted: Tue Dec 28, 2010 11:38 pm
by zelph
Yah, mine is a maglite. I'll see if I can find it and soak it in something to get it open. Pipe wrench would do it but don't want to go that route yet :mrgreen:
Permatex battery protectant
thanks for the name. will get some and put it to good use :D

Where are you going to put your new led light?

Re: Mid size LED flashlight.

Posted: Wed Dec 29, 2010 11:03 pm
by Bfinnigan
If you get the battery protector you really have to turn it upside down and spray it after using it. I have wasted several cans by not clearing the nozzle after using it. Then it gums up and won't spray. But once a year on your car battery terminals and they will never corrode.

I'll probably just use it for day hikes as a back up to my head lamp. A lot of the stuff I make I don't have an immediate use for. I just get an idea and go for it. Eventually it all gets used. I want to make a larger multi D cell unit and 30 LED lantern.

Re: Mid size LED flashlight.

Posted: Fri Dec 31, 2010 4:53 pm
by zelph
I do the turn upside down with all paint cans so I'll be sure to do it with the terminal stuff.

You've got ideas that will keep you busy for a lifetime :D

Same here :lol: Never a moment goes by without a new idea. Something ventured, something gained. ;)

Re: Mid size LED flashlight.

Posted: Wed May 30, 2012 4:30 am
by Nery Britz
I took my time on this and got it very tight. It's time consuming but I am never in a rush making things.




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http://www.youtube.com/watch?v=anwy2MPT ... ata_player

Re: Mid size LED flashlight.

Posted: Wed May 30, 2012 8:39 pm
by zelph
:D ;)