MRTdiver's custom Minimag build thread - Updated "Tests and Beamshots"

The Fins
The Head
The Driver
The Noctogon
The Tailcap
The Battery Tube
Done, Almost
Tests and Beamshots

The lucky winner chose a pewter Minimag with a triple Nichia at ~2.2A and cut down for a 14500 cell. The driver will be a Qlite 105C set for 15/100 with 6 - 7135 chips.

This light will have the copper fins I did for DBCstm’s light so the first thing to do is to make that part so I can mill the head and pill to fit it. One obvious difficulty is I will have to turn the triple pcb down to fit but I’m sure that won’t be the only trouble.

The pill will be made from copper repair tubing. It’s the same size as 1/2” coupler but comes in 12” lengths. I’ll take a piece of 3/4” pipe and resize it to fit snugly around the repair tubing. This is the part which will have the fins soldered to it and be epoxied with AS5 into the head leaving the fins exposed.

The host and some copper.

The 3/4” pipe section with ~7mm removed.

I annealed this piece on the stove, then slipped it inside another 3/4” pipe with the repair coupler inside it and rolled it round to resize it and maintain an even cylinder. Some filing and more rolling led to a snug fit around the coupler.

The OD of this piece is just under 3/4” so I set up the drill press with a 3/4” hole saw and punched 5 holes in a strip of copper, then reset the strip to punch out the rings with a 1 3/8” hole saw. This will leave plenty of excess to trim even.

A bit of clean up and sanding the ID and the rings are a snug fit around the first piece.

Before I solder this up I’ll anneal the rings and flatten them between metal plates in the vise. I’ll use some thin copper wire to space the rings evenly but more on that next time.

Do you often get called a freak? I’ve pulled up my favorite chair, grabbed a beer and turned the HTPC on the 50’’ plasma waiting for the next instalment. Gotta love these builds. :beer:

Very nice, can’t wait for some more! :party:

Yeah Baby! The BBC 261L’s big brother is coming!

Looking good, off to the races! :slight_smile: This should prove very interesting, I’m pulling up a chair beside Steve…popcorn? :slight_smile:

I’m really liking how easy it is to make fins this way. It’s still tedious but the payoff is in how much more even they are than with the “drill press lathe” method. I’m still pretty busy at work so the next segment will be Wednesday when I solder this part up. Then the weekend to bore the head.

Will you be making the "pill" from scratch or using a drop-in?

And have you considered a spacer on both ends so that the first and last fin will have airspace on both sides? If not, the 1st and last are up against aluminum, don't know if it'd be more or less efficient, just wondering.

Scratch made pill from 1/2 pipe, repair coupling, sheet copper, and noctogon triple turned down to ~17.5mm. All of that will be a press fit into the finned part with the driver potted inyo the other end. The bezel snugs up against the first fin and the head grip snugs up against the last one. This light will get an extra fin as well. As short as it will be I may retap the tail cap threads instead of doing a continuous inner sleeve as with the BBC261L.

Gonna look pretty amazing in that larger format too. Will be watching...

watching too :-)

I think someone is really going to like this

I have the "prototype", trust me, like is too mild. ;)

MRTdiver, did you see it? Wanna see it? :)

Naaaaa, that'd spoil it.....:P

At ~ 350 mA a Nichia 219 specs between 110 and 150 lumens and roughly twice that at 750 mA depending on the bin. 3 LEDs would spec at 660 to 900 lumens but since I probably got a lower bin 450-500 would be more likely. BBC500L?

Be neat if it works out like that, being as how it'll be running a 14 500 cell. But you probably won't see that OTF, maybe , we'll see huh? :)

For the record, my lightbox reads 333 at 30 seconds. Just sayin! ;)

Edit: In my experience the only cell that reliably allows 3A in that form factor is the AW IMR14500. Lesser cells won't pull it.

We’re planning for 6 chips or 2.2-2.3A and if his cells can’t supply that hell get some imr’s. I’ll test the driver with an efest 14500 first to verify it before installation. Twice the overall current with 3 times the LEDs as 261L. The lower drive current per led should increase efficiency but since the Nichia isn’t as potent as the xpg2 I don’t expect any miracles. I think it really depends on the bin of the Nichias.

RBD - I just love watching you do your thing!Smile

Finally got back to the shed tonight for some swearing and crying I mean sweating and grinding. When we last were all here I stopped with a slightly smaller copper cylinder and some discs. The discs I annealed on the stove top and flattened in a vise between two steel washers.

Then I took some plain awg20 copper wire and wrapped enough around some pipe for the 5 spacers that separate the discs.

Then I carefully worked it onto the cylinder to size the diameter.

Then I just cut the wire in a line down the cylinder making 5 wire rings exactly the right diameter.

Then I fluxed the cylinder and put the discs and rings on and cooked it over a low heat and added some solder.

Oops! It’s crooked. !#%. I had to clean it up, reflux, and reflow it a couple of times before I was happy with it.

A little preliminary clean up then it’s off to the drill press.

And here’s how it looked after about an hour and a half of sanding.

Right now it’s still a few millimeters larger than the Minimag head and I think I’ll leave it the way. Next episode I’ll bore out the head and cut it to allow the fins to sit between the bezel and the head grip.

update

Upon further consideration MRTdiver decided it would be better to have the fins flush with the rest of the head and aestheticly I agree so I chucked it back in the drill press and sanded it down until it was ~.2mm over the head Dia. With the fabrication done on the pill and driver I went ahead and epoxied it into the head with JB weld. Can’t make it bigger now.

This was the best of about a dozen pics and I give up.

Coming to a theater near you. :bigsmile:

Simply orsm Rufusbduck. Seriously I have no idea how you guys do these amazing things until you explain it in pictures. The light OL is building I was stuck at getting the reflector to fit in the head as I could not hold it in the lathe. It wasn’t until a member here posted pictures on using a drill press as a mill/lathe that it all twigged. Thanks. :beer:

Awesome work Rufusbduck. Its always amazing seeing what some people can do with just common tools and their hands. Simply amazing work, I am impressed. :wink:

That’s it, I’m packing up my gear and heading over to your shed! Photo documentary and video light modding 101! :slight_smile:

As always, beautifully excellent work there Scott! And as always, the extra mile has been run, surpassed, and fine tuned.

Steve said it well. ORSM!