CRX Underground Mechanical Mods

I quite liked the look of this one from Ali-Ex. Underground MCM mechanical mod.

This is a stackable 21700/ 18560 mechanical mod, comes in various coloured coatings and the extension stacking piece is just a few dollars more so I bought the two as I saw potential in both pieces.

These are well made solid chunks of brass for the price and come with copper button derlin cell holders, silver plated ultem switch and a clip sealing plastic foam lined box.
I did order the plain brass version but it was out of stock so accepted the black coated instead.
Main unit with extension piece:

The painted coatings are not very durable and scratch fairly easily. I used acetone to soften it then wire wool to take most of the coating off from the outer shells leaving some black in the machined grooves.

So what can I do with these things?... :)

Main MCM Underground mechanical mod build:

CRX Underground MCM Triple Nichia 219C 5000K - Lxl TA Driver - 18650 - Piston Drive E-Tail Sw - 2430lm.Triple Nichia 219C 5000K emitters
LED4P Copper DTP MCPCB
Carclo 10508 optic
22mm x 1mm ARC glass
Hand made GITD dual colour glow gasket
Lexel 22mm E-switch driver
Anduril firmware
Copper pill
Copper lined body
Copper tail switch internals
Piston Drive electronic tritium tail switch

Max - 2430lm
Throw - 122m
Length - 90mm
Width - 28/ 31mm
Weight - 260g (With 18650 cell)

CRX Underground MCM Triple Nichia 219C runtimes:

This was a difficult build due to the size restriction of 90mm but I managed to make it a piston drive, the electronic switch is mounted on the driver board so the cell is the piston to operate it.

Copper lined throughout for mass and heat distribution.

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Part two, extension piece build:

Again I stripped off the black coating and cut off the protruding front thread to use as the screwed bezel for the piston drive light.
I took some build pictures with this part.

The lights are built pretty much the same way with copper tube throughout.

Pill:
22mm x 1mm copper tube pill housing, brass centre pill with driver retaining ring, 22mm x 1mm glass, 22mm brass bezel.
Convoy 8x7135 driver with brass button, Nichia 219C 4000K 90CRI emitter.

Body liner section:
22mm copper tube, felt lined with brass insert for o-ring placements.

This extra copper helps transfer the heat from the pill all the way down the body of the light and provides good fitment for the 18350 cell.

Tail switch unit:
I potted the reverse clicky tail switch into some 22mm copper tube and soldered to the brass 510 hybrid threaded piece so we can have a screwed tail cap.
This unit butts down onto the body section compressing the 22mm o-ring on the brass tube insert.
The brass 510 threaded piece has some nice shapes cut into it so I filled them with a thermochromic/ GITD powder mix.
At cold temperature the inserts look black but with some heat and applied light glows bright green.
In order to have something to grip when tightening the tailcap down I installed four brass pillars around the switch, filling the already present vent holes.
These are 2mm hollow brass tubes filled with aqua blue glow powder.

Parts:

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Complete:

CRX Underground MCM Nichia 219C 90CRI - C-MK 3A - 18350 - Rv Clicky Tail Sw - 600lm.Nichia 219C 4000K 90CRI emitter
Copper DTP MCPCB
22mm x 13mm OP reflector
22mm x 1.5mm ARC glass
Hand made GITD glow gasket
Convoy 8x7135 3A driver
Biscotti firmware
Copper pill
Copper lined body
Copper tail switch housing
Thermochromic Black/ GITD tail
Reverse clicky tail switch

Max - 600lm
Throw - 128m
Length - 75mm
Width - 28/ 31mm
Weight - 232g (With18350 cell)

CRX Underground MCM Nichia 219C 90CRI runtimes:


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Other Mechanical vaping mods I have made into flashlights:

CRX RV Titan I Triple Nichia 219C – Anduril – 18650 – E-Tail Sw – 2200lm.

CRX RV HammerHand Nichia 219C 4000K - LD-A4 - 18500 - Halo Tail Sw - 740lm.

CRX RV Titan II LH351D 5000K - LD-A4 - 18500 - Halo Tail Sw - 1200lm.

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Really cool looking, CRX!

What’s the advantage in going with a piston drive?

Btw, link you provided fails on AliExpress: https://www.aliexpress.com/item/33053814317.html?spm=a2g0s.9042311.0.0.75b04c4d2CCngN

From another World….thanks for Showing :open_mouth: :+1:

Your Skill has no Limit :smiling_imp:

Thank you for posting this more detailed thread on these builds. I absolutely love both of them, and I really want to try that GITD powder now.

Awesome conversions CRX. Your attention to detail is always impressive, I really like the look of that glow tail switch.

Without the black trim it would look a lot like your other builds made with brass nuts.

So we going into business now then lol :stuck_out_tongue: , I find the hosts you do the mods - like wheeler dealers! (I presume you’ve watched that, I love it lol)
Just kidding lol, mate it’s awesome - a true chunky munkey!
You always inspire, and it’s true seeing your stuff has made me pull my finger out and actually start doing stuff - bending your ear along the way obviously!
So glad people like you, PP and all the other wonderful modders keep this place alive - it would just be lights for sale and off topic chatter otherwise.
Well done. :+1: :beer:

That MCM logoed light looks amazing, in fact it might be the best looking light i know of. Nice!

Beautifully designed and crafted lights. :+1:

Simply wow. Nice work CRX. :beer:

Nice work, as usual sir.
And to think, I’ve been tossing my dead vape mods all this time. The Pico is my favorite travel vape, and use the 21700 versions when out and about.

Link should be fixed.
I did intend to go the usual route of an e-switch in the tail with a signal tube but was too limited in length, I had to bore out the end cap to take some of the 18650 cell so it was easier just to mount the switch on the driver.

:beer:

:+1:

Yes I like the contrasting black, breaks it up a bit :+1:

Yeah you’re annoying but have some good ideas too so I tolerate :smiley:
You’re right, this place is getting like social media sites with all the nothing to do with flashlight junk threads.
That’s partly why I post my stuff too, to show what you can do with some simple hand tools and perseverance.
I used to watch wheeler dealers until Edd left. Mike does my nut in :smiley:

Yes, I like it too, something a little different :+1:

:beer:

:+1:

Send your broken vape mods to me :smiley:

Way cool! Great stuff. Looks like there is no end to your imagination and workmanship. :+1:

Same with you Don :wink: :+1:

Awesome job CRX - that’s a cool looking flashlight! :beer:

:slight_smile: :+1:

That switch!! do you need a kidney?

No I’ve got some on order from alibaba :laughing:

So……will you be offering these any time soon? Love the look (and the ability to stack them). I’d be interested.

Also, AliExpress link appears to still be broken.

What!? I just fixed that. :laughing:
Maybe you need to be logged in for it to work.
I think the true price of making these to sell would scare people here.
Parts alone are around £60 and 10hrs labour for the triple. About £40 & 8hrs work for the single emitter light.
Hit me with a number if you like and I’ll tell you higher or lower :smiley:

Beautiful as always