SO I had a project where I needed a specific size of beamsplitter and I needed it quickly. Unfortunately, the type I needed wasn’t available from the usual sources, at least, not without a few days of lead time. What to do? It turns out, crazier people than me have been using CNC machines to cut glass!
So, I made a jig from acrylic, and cooked up a hold down method, and voila, after a few attempts and figuring out how to hold the part, I was able to cut both sides of 2 of these small beamsplitters successfully! Unlike the linked example, I simply used water as a coolant, and submerged the workpiece in a recessed channel in order to provide cooling during the cut. I used a dremel diamond engraving bit, likely not the best choice, but it’s what I had avaailable. Feed speeds were @ 0.61 IPM with an RPM on the spindle @ 2600. Finish was a bit rough, but definitely useable! I figure the difference between my work and the example above is the end mill selection. Anwyay – If you ever find yourself in a similar pickle, and have access to a CNC, it might be worth a shot.