Thanks for the support! The bits are actually 2mm diamond cylinder bits intended mostly for dremels. I did a bit of experimentation and settled on 2mm, because 1mm breaks really easily and 3mm is too slow and wastes too much material. Like this: https://www.amazon.com/Diamond-Grinding-Cylinder-Coated-Mounted/dp/B07S6T3ZRP Yeah the noise is loud enough to hear on the next floor up. I held off until I moved out of my apartment. Earplugs are a must.