Brass Braille Beads. ADA-compliant Raster Braille Spheres for Signage and Wayfinding. (1000)

These: https://a.co/d/09JYp1Kf The 1/16” bit makes a hole slightly smaller than these, so you can go through, fill it with barge cement, and sort of press the ball right in. Clean up the extra and it looks nice and neat.