Designing a can light

yorkie_chris

Newly Enlightened
Joined
Apr 27, 2012
Messages
75
Hello folks,

I'm just in the process of designing a can light.

Helpfully I live really close to troutie so I'm going to go see him and buy some ahorton aspherics.

I'm planning to put an XML behind, with an SKU 127684 5 mode 2800mA driver. Though, I only want a single mode (on!), so I'm going to order a few and try and bodge it so it's simply on and off. Has anyone got any experience of these? I don't want something that's going to be a pain and accidentally drop onto SOS mode or something daft!

No quite finalised how I'm going to do the body yet, I have a lathe but my screwcutting is a little dodgy so I'm trying to keep that to a minimum, also I'm limited on depth of boring so I don't want any fine features at the bottom of a deep hole. I'm thinking of using tubing for a lot of it. I'll stick some drawings up in due course :)

I have a few questions for anyone who knows, hopefully not too ignorant sounding.

Is there good reason not to use the body of the torch as electrical contact? I'd be relying on a threaded fit between body and tailcap for conductivity, all aluminium.
Looking at greenforce cable, they use a fancy plug with copper contacts for -ve and +ve.

Cable glands; I've seen these
http://www.scatts.co.uk/PDFCat/559-1.pdf
Which look nice, and should be strong, but am I going to give myself a big corrosion headache putting nickel plated brass into aluminium?

Also sealing the glands, I thought to cut a fairly tight thread, and use some loctite 542 or similar thread sealant. Is this the done thing or do you add an O-ring/dowty seal?

I'm yet to design the canister properly or choose a cable but thinking of 3S3P NiMH C cells, if it will be small enough.

Many Thanks
Chris
 

350xfire

Flashlight Enthusiast
Joined
Aug 14, 2008
Messages
1,229
Location
Texas
Mainly a thought on cable gland- the Lapps look nice but not as good as the Agros. The Agros have the built-in strain relief.

You have a lathe so easy to mod a Maglite.

Battery, I like LiIon.
 

DIWdiver

Flashlight Enthusiast
Joined
Jan 27, 2010
Messages
2,725
Location
Connecticut, USA
I just dove my XML/Ahorton light this weekend, and I'm very happy with it. Good luck!

I wouldn't think 3S NiMH would be quite enough to drive the XM-L. There's going to be a little loss across the driver, so you're going to start losing light before the battery is even half drained. I'd go with 4S. Of course that might be a bit much for that driver when fully charged (5.6V or so).

You can use the body for a conductor. MAG has been doing it for decades. So has everyone else. I don't quite understand how, but it seems to work.

On the other hand, I'm having a little problem in my light, losing about 0.3V somewhere (low battery indicator comes on too soon). It only happens when it's all together so I'm having a hard time figuring out where it is. Could be in one of the body connections.
 

Packhorse

Flashlight Enthusiast
Joined
Nov 29, 2007
Messages
1,912
Location
New Zealand
I really like the Ahorton aspheric. If you are after a small light head then its the way to go.
But the DX44mm aspheric fits great in a maglite and produces a tighter more intense beam.
My 44mm aspheric XML mag is my goto light.

Unsure what driver you refer to as you only posted a SKU code that could refer to one of a million web shops. But I use this driver and convert it single mode with ease.


I would avoid using the body of the light as part of the circuit for a number of reasons.
1. its hard to get a reliable contact with aluminium.
2. you run the risk of galvanic corrosion.


Agro glands are the mutts nuts, the bees knees, the shizzle on my nizzle.
 

little nick

Newly Enlightened
Joined
Apr 21, 2011
Messages
39
Location
Devon - UK
I have a XML under an Ahorton aspheric, which is a great combination. I drive mine from a 12v NiMH pack - as I converted a Diveright canister light.

There are simgle mode drivers off the shelf. I have used ones from KD (SKU S020082, 6-15V, 3A Circuit Driver for Bike Light - which comes with 2 boards, the lower one can be rmoved totally, as it is desighed to be a battery contact) and the other is from the CPF member Der Wichtel (Seoul P7 / Cree MC-E Buck Converter)

I am in mid build of a Mag build, XML under a DX 44mm aspheric - which I can't wait to finish - but DX sent the wrong lenses. Hopefully it is only a batch problem & they will have the correct ones in soon.
 

yorkie_chris

Newly Enlightened
Joined
Apr 27, 2012
Messages
75
torchhead.jpg

Quick drawing of light head.
Rearward of 3x O ring grooves on inner part will be M36x2 thread, screw/unscrew this to turn on and off
 
Last edited:

DIWdiver

Flashlight Enthusiast
Joined
Jan 27, 2010
Messages
2,725
Location
Connecticut, USA
You won't need the snap ring in front of the lens. My first light has only one o-ring groove in the lens, and it's a b---h to get it out after it's been in a while. I finally built a dummy plug with a tire valve in it so I could blow it out. The snap ring only closes down the aperture, doesn't hold the lens in. Besides, unless you make it out of aluminum, it will be a galvanic corrosion problem.
 

yorkie_chris

Newly Enlightened
Joined
Apr 27, 2012
Messages
75
I didn't want to make the lens itself an interference fit, was worried about snapping the tops off the O ring grooves.

You reckon the O rings themselves provide enough friction then.
 

350xfire

Flashlight Enthusiast
Joined
Aug 14, 2008
Messages
1,229
Location
Texas
You should check out Will's (wquiles) hand held. It will show you how it should be done. He placed an oring under the lens and one over it. The oring over the lens applies some pressure to hold everything together. Really nice way, however, has to be "engineered" properly. I think you can find the thread under "magnetodrive".
 

DIWdiver

Flashlight Enthusiast
Joined
Jan 27, 2010
Messages
2,725
Location
Connecticut, USA
I didn't want to make the lens itself an interference fit, was worried about snapping the tops off the O ring grooves.

You reckon the O rings themselves provide enough friction then.

Yes, my lens has free clearance in the head, drops in and out with gravity if there's no o-ring in it. Put in the o-ring with a little silicone grease, and it goes in with firm finger pressure. The great thing is that there's never any pressure behind it to push it out, so even a little friction is enough. But I calculated the proper compression for a static seal, and after weeks of sitting, I think it required between 30 an 100 lbs of force to push it out. Of course I'm only guessing at the pressure that was behind the 3 sq in of lens before it popped. It was more than a few psi and less than a lot. If that's not ambiguous enough, let me know and I'll increase the range;).
 

yorkie_chris

Newly Enlightened
Joined
Apr 27, 2012
Messages
75
Last edited:

DIWdiver

Flashlight Enthusiast
Joined
Jan 27, 2010
Messages
2,725
Location
Connecticut, USA
Sorry can you increase that a bit I'm not sure rigging the light body up to a 232bar tank will be spectacular enough, should I upgrade to 300bar kit? :p
Somebody did say they wanted a light cannon...

Funny you should say that, just as you were writing it I was out playing with my air cannon, which I charge using my scuba tank which is normally filled to around 200 bar. Of course I was only charging the cannon to 1.6 bar (gage) as I didn't want to be killing the neighbor's kids.

I suppose I could increase the range as far as 12 bar, but as that's around the intermediate pressure in my reg, it couldn't have been much higher than that. Sorry to disappoint you. But I think 232 bar would be plenty to provide excitement if introduced directly into a light body.
 

yorkie_chris

Newly Enlightened
Joined
Apr 27, 2012
Messages
75
I once got into significant trouble for playing with cannons. Saw people making PVC tube hairspray cannons and decided to go one better and make one from steam pipe... then started experimenting with oxygen and acetylene. Scary bit of kit.
Funny enough the armed response unit didn't think it nearly as funny...
 

yorkie_chris

Newly Enlightened
Joined
Apr 27, 2012
Messages
75
went to see troutie the other day who's on here and had a nice chat with him, sourced XML, TaskLED driver, ahorton lens and got a lead on where to find good quality assembled battery pack :)
 
Top