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!
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.
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.