Modding Kensun Tailcap to fit a normal switch

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 :smiley:

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…

4 Thanks

Great work! I really appreciate the pics and write-up. I’d like to do some mods to budget lights and this is very inspirational.

A dirty mind is not always a joy for ever. Seeing the transformation from nice to great, I looked at the pictures of the in-between and could not help but thinking about Lauren Sánchez. Gut-wrenching.

Nice mod. It is good to see some lathe work around here! And 3d printing too.

What do you think about tail mounted drivers? Doesn’t seem very common.

1 Thank

This was my first light with that and I got rid of it as fast as possible :smiley:
I don’t see the advantage aside from it being two cents cheaper.
Makes it harder to mod the light and doesn’t even save on PCB or manual soldering since you need the PCB in front of the battery and leads going to the LED.

I looked, what could fit in there. I think I could make a 4x519A from Convoy work in there. The lens and MCPCB do not fit, but a little bit of grinding will make it fit, it’s just 0.5mm too much diameter or something like that.

Does it run an E-switch firmware?

Nice mod L4M4!

Someday I want to get a lathe to be able to do stuff like that.

There’s just something so neat about lighted tail switches. :sunglasses:

Looking forward to see how you mod this even more.