Build thread for the M&M Mini

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Rufusbduck
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Build thread for the M&M Mini

Ever since I first saw the chopped Minimag in EDC’s avatar I have wanted to make one, even if it wasn’t as perfect as that. Since then I found that 2 members here have made an art form of this mod and the M&M is named in their honor, Match & JohnnyMac. Over the past few months I have been reading over and over the build and for sale threads for each of these that I could find and decided to try and make one for my 1K giveaway. I am quite happy with the results and learned a few things along the way that I’d like to share.

For me, the first step after disassembly was removing half of the male thread portion of the battery tube. This was done by first wrapping the tube in blue tape and then cutting it with a radial arm saw(old Ryobi 8” model with carbide blade). Overkill I know but it’s what I have This allowed me to then enlarge/deepen the reflector hole to the point that the remaining male threads would reach just above (1-2mm)the new “step” when screwed in all the way. My method for this was to drill a 1” hole all the way through a 1×4 and 1/4” into another. The AA mag head is a snug press fit into the top without bottoming out in the lower piece. Drilling the head was done with a 3/4” hole saw on the drill press with plenty if lubricant and frequent removal of shavings. This creates a flat bottom step rather than a bevel from using a standard bit. I realized later that by increasing the set of three teeth equally spaced around the hole saw I could effectively increase the drill diameter a bit(set is the alternating bend of the teeth on some cutting tools). For this one I finished it with a dremel and then a 3/4” dowel wrapped with ultra fine wet/dry sandpaper. Once that was done, I could measure the depth and creat the pill.

p. The pill was made with my usual method of sleeving successive layers of cu tubing or cu sheet sized to need. I keep repair coupling which comes in 12” lengths rather than the short pipe couplers as it is easier to hold and cut small pieces from a much larger one. Also, 1/2” coupler is ~1 mm larger od than the 105C driver I planned to use. A piece of 1/2” pipe 2mm shorter to allow for the chip height went inside of this and a piece if 3/4” pipe, cut and resized to fit snugly around the outside plus 2 discs cut from flattened coupler stock (heavier guage than the sheet stock scraps I have) completed the parts for this part if the pill. Once soldered together, they were filed and sanded until the pill was a snug press fit into the head.

Because it has chips on both sides the 105C driver has only a narrow ground ring which is inadequate for this build so I cut another disc of thin sheet stock this time and drilled holes in it matching the 3 vias in the ground ring of the driver. I plated this on one side with solder using a 200w iron (gas stove and a soup can lid works as well) and then redrilled the holes through the solder. 3 pieces if thin guage solid cu wire were then soldered to the driver vias, AA applied to the tops if the 7135 chips on the spring side and the now plated disc threaded onto the 3 wires and clamped to the AA topped Chios. Once this had set, the wires were quick soldered, cut, and filed down smooth. A portion if the disc covering the stars was removed to allow mode afterwards. Wires were then added to the output side of the board and after trimming and tinning them it was fixed into the pill with Fujik. After installing the LEDs, they would be sinked to a pill that did not have direct metal to metal contact with the driver. The heat path for the LEDs flows through the pill and into the head but the path for the chips is through the plate to the battery tube. It may be moot since they are so close together but that minimal separation may help maintain driver operation.

I operated on the tail cap next by removing the portion above the threads and soldering a plated spring to a short piece of cu refrigerator tubing that press fit into the center hole and then ground off all the threads but for a shallow line showing where they had been. Holding the now thread less tail cap in the the battery tube I dropped in 2 cell to see how much stuck out the other end both compressed and uncompressed. Allowing for the positive spring on the driver and compression of the tail cap spring, I taped, marked, and cut the battery tube so that when off the battery did not rattle, and when on, the springs were not fully compressed. Then using a dremel, I reamed out the battery tube until the the tail came just short of seating fully. I put the battery tube on the soup can lid on the stove at very low heat and put the cap in the freezer near the fan, made up some JB weld, and put some tape on the vise jaws. When it was mixed I put on some gloves, took the cap out of the freezer and filled the groove where the o-ring had been with JB, dropped the cap into the battery tube and put it in the vice for a nice warm hug. I wiped of the excess and wiped it again with brake cleaner to remove any residual epoxy in the knurling and set it aside.

p. I had often wondered if it would be possible for me to do fins and recently came up with and idea I thought might work. I don’t have a lathe or Justin’s steady hands but I have a small drill press with a hole in the center of its table. When making the brass sleeve for the solitaire I found the bolt fixed only into the church wobbled producing a cut of uneven depth but was able to eliminate thus play by using a longer bolt that went clear through the work and the table with a bushing in the table to stabilize it. After that, the block of wood with the hack saw attached worked extremely well and I’m confident that with a bit more practice I’ll be able to do more passable work. The pictures show neither how good nor how bad my machining is and while not anywhere near good enough for saleable work, I think it just fine for friends, family, and hobby work. DIY indeed.


p. I can’t wait to make one again! Thanks for the read

Three Tanna leaves to give him life, nine to give him movement. But what if he eats the whole bag?

Scott

ruffles
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Thanks for sharing. I’d love to see more pictures of your pill the next time you build.


 

mattthemuppet
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great job there, especially with finning the head. I think it looks fantastic and I doubt anyone would ever be able to tell it was done Macguyver style instead of on a lathe Smile

and to do it all to give away is even more awesome!

Rufusbduck
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I have a small box full of failures. This was one I got right the first time. Making all three lights I didn’t stop in the middle for pictures but now that the process is known for each one it will be easier to document. As with when I was climbing, you don’t take pictures when your flailing.

Three Tanna leaves to give him life, nine to give him movement. But what if he eats the whole bag?

Scott

Itinifni
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Nice job!

I’d also be interested in more pictures of the pill.
I have a new incan MM sitting in the basement and have been thinking about trying a triple, haven’t decided whether or not to cut it down. Run time would be better with 2 14500s but then again how much run time is realistic with the heat issue.

I remember a time, when I searched for lights to fit my needs. Now I search for needs to fit my lights.

MRsDNF
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Orsm job Rufusbduck. Another inspirational job by a vey talented person here. Cant wait for you to put your 3 of 3 build up. Thanks for showing.

 

djozz quotes, "it came with chinese lettering that is chinese to me".

                      "My man mousehole needs one too"

old4570 said "I'm not an expert , so don't suffer from any such technical restrictions".

Old-Lumens. Highly admired and cherished member of Budget Light Forum. 11.5.2011 - 20.12.16. RIP.

 

Rufusbduck
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How bright for how long? Multi mode drivers allows both so it really depends on what you want to make and then carry. As with my TF mini, this one should probably only be on high for a few minutes at a time but it could stay in a lower mode all the way down. I’ll post a thread in a few days showing how I make a pill for this but they are often driver specific.

Three Tanna leaves to give him life, nine to give him movement. But what if he eats the whole bag?

Scott

keltex78
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I just received this light in the mail this afternoon and it is an incredible build! It looks like something that Mag should manufacture as an OEM piece of equipment...

Overall, the light fits together perfectly, is very nice and clean, and as a shorty, is extremely pocketable.

The fins cut into the head look great, and give this light a very distinctive appearance:

I haven't gotten to take it outside yet for some serious fun, but just playing with it here, I'm extremely impressed; this is an extremely bright light! it appears brighter (visually) in both lux and lumens than my XML-U2 modded Trustfire F20. I haven't had opportunity to compare using my light meter yet. The tint is also much warmer, surprisingly so! This is just a simple beamshot against the door to give a general idea, but it shows the intensity of the hotspot, as well as the increased hotspot width and increased spill. My F20 did not appear to be such a cool-tint emitter until I put it next to this light...

Very nice light, I'm very happy with it, GREAT WORK Rufusbduck! Thank you very much for the generous giveaway! I have entered many, but this is the first (so far, only) one I won; I'm very happy it was for such an awesome light!

And this thing gets HOT on high! Just a minute on high was enough to make it uncomfortably hot around the head...


Keepin’ the “B” in BLF

Don wrote:
It sounds like the XM LEDs won’t really be suitable for flashlight use. Pity…

Rufusbduck
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Thanks for the kind words. Every time I see an EDC post I drool over his MiniMag and finally just had to make one. Now I’m getting a AA mag from Oldlumens. What goes around… I’m not going to touch his file work but I may pick up a 14650 imr and shorten the tube.

Three Tanna leaves to give him life, nine to give him movement. But what if he eats the whole bag?

Scott