I received a light from the “brand” Kensun a couple of days ago.
It is this one: Wasserdichte starke Licht laterne Hochleistungs-LED-Taschenlampe mit fluor zieren dem Logo Typ C USB wiederauf ladbare ultra helle Taschenlampe - AliExpress 39
While taking it apart to inspect it for my other thread: I bought a bunch of cheap flashlights from AliExpress - Thoughts - #43 by L4M4
I unfortunately noticed, that the driver is indeed in the back and in the front is just a plate with a resistor and a diode.
Since I do like the general optics of this light, I did think a lot about it and wanted to put a normal lighted clicky switch in it. But how? How to open up a tailcap that has already two off center holes? I don’t have a mill, I “only” have a lathe.
Yesterday night I had the Idea while laying in bed.
I have router bits. With those I can open up the two holes so that a boring bar fits. And today, I started the conversion.
FIrst a couple of pictures from my review thread so that you all know what this is about
Then it began… I decided for the round router bit because I imagined the pointy 90° one to be too harsh
Added some clothy tape around so the tailcap doesn’t get scratches
At the round hole you can see that I tried to hand-saw it first, but the aluminum did clog the sawblades with one stroke, so I quickly gave up.
Looking good so far!
Done!
Next the 16mm hole bit
This went way nicer than I imagined
After the boring bar
The parts. I had to turn around the retaining nut and drill two holes into it. Also had to open up the hole in the middle from 10 to 12mm so that the spring doesn’t touch the nut
I 3D-printed two parts from PETG-CF One adapter to make it all fit, one retaining ring that keeps the silicone cap and the clear plastic ring down and centers the switch-PCB.
Nice press fit
With the retaining ring pressed in
Well, it all fit very nicely.
Looks nice from the outside, as well…
But it didn’t work. When I did start the thread on the tailcap, it worked, but the more I threaded the cap down, the more pressure got onto the spring and the silicone part did compress, which did result in the switch PCB pressed too far down for the aluminum nut to touch. Solution: Add some solder on the PCB after some grinding of the 3D-printed part didn’t do it.
A clear tailcap is in the post, at 14mm I only have green, orange and black ones in storage.
Lights up, brighter than before and only one mode of course.
And it even tailstands

I am very happy with this mod. Everything worked out fine and now I can start modding this light even more. Install a driver (17mm), install some other LED and probably optics or reflector, maybe even triple-LED, I’ll see…