Perfect geek/nerd clock for mathmatically inclined, or engineers like me :) Made this for a fellow on Facebook's 3DP Rescue group. There are 2 versions, raised letters for single color printers and flush lettering for multi-color printers.

There are clock kits such as https://www.amazon.com/dp/B0BW41DYMS?ref=ppx_yo2ov_dt_b_product_details&th=1 which are very inexpensive. The clock face is 3mm thick, the hole in the middle is 8mm and you can make it larger by using a cylinder negative part to increase the size as needed (in my case, my clock hardware is 14mm center hole).  In the version with raised letters, the letters are 2mm.