0.1mm: https://www.aliexpress.us/item/3256801655537532.html https://www.aliexpress.us/item/3256801655537532.html I would not expect you to be able to use bits

0.1mm: https://www.aliexpress.us/item/3256801655537532.html https://www.aliexpress.us/item/3256801655537532.html I would not expect you to be able to use bits this small without special machinery. I've used similar 0.8mm drill bits by hand, and they were fragile enough.