Video showing how to slice the dome off an LED with washers

LED used: LH351D (depending on your LED you may have to find other size washers, dont try the same size washers with a XHP50/70 or SST40)

Razor blades: any new double edge razors are fine. A lot of people use Wilkinson, I use these Feather brand.

Washers: various sizes but the final washer is .92mm thick if my calipers can be trusted. the next two up are 1.21mm and 1.54mm but these are a lot less important you just want to take like 2/3 of the dome material off before the final cut or else the entire dome will try to peel off the LED at the end of your cut.

Apologies for not having the best angle during the actual slice. I set up the shot before I realized I am not ambidextrous when very fine motor skills are required.

Due to trying to make this look good on video I also held the blade at too much of an angle. They bend so it’s not that big of a deal but try to get the blade a bit flatter and parallel with the washer.

Finally, when I do any modding I always use isopropyl alcohol and a q-tip or something similar to clean the LED. The razors have wax and who knows what else on them. Between that and solder, flux, thermal paste, just clean them all the time!

Also if you came here looking for how to do a XHP50/70 please refer to ZozzV6’s thread here:

He already made an excellent write up and video showing the additional steps which are required for those larger LEDs.

Thanks contactcr.

Thank you for mentioning my thread :wink:

Thanks for the demonstration.

I think using smaller diameter washers work even better, since it wont allow any unwanted rotations or angles, someting that is allowed using the larger washers/ shims as shown in the video. (The corner of the razorblade tends toward the LED in the video since it is not supported by the washer)
Then a clean and straight cut will be easier to achieve by using the whole washer as a support.

Thanks for the video, very helpful! I had a few emitters arrive today for the purposes of slicing. Still need to get the right sized washers.

It’s true but the first priority is finding the right thickness. It’s a bonus if you can find a nicely sized hole but ultimately without fabricating something it might be hard. I still mess one up every now and then since I insist on making a very close cut.

Well demonstrated contactcr.

I suddenly had a thought while watching the video.

What if instead of using washers you used feeler gauges. Buy a set and drill a 6-10mm (1/4-3/8 freedom unit) hole through them. Stack them to very precise heights.

Good idea , Nooner !

That’s what I use. If you buy the right set you can do 3535 LEDs using the hinge hole without even drilling anything. Best to deburr the hole so the razor doesn’t catch the edge though.

Well done is always better than well said.
I thought I was clever but Bob McBob is already on it.
Nice to know it works.

I suppose that with the right tools you could slice it on the final pcb without using a dedicated one but washers are cheap and easy to find

What about using a chistle ground rasor blade instead of a v grind?

contactcr Do you have a Caliper to measure the thickness of the 3 washers—Thanks

It’s in the first post

Yeah, very nice. I really like that it’s possible to use the existing hole instead of drilling new ones. :+1:

Did you just add that info / are my reading /comprehension skills that bad :person_facepalming:

How to do : Dedomed xhp70.2 inside a flashlight?? bcos it seem glued permenently… I can only open the head benzel and glass lens. Now that sound like a challenge…anyone?

Nice job on the video Contactcr :+1: .
That should help get more domeless leds floating around.
I really like the magic shaving can do with some led tints.