Next Level Spirit Level (for billiard / pool table)

Leveling a billiard table to an exact horizontal orientation requires a very accurate "spirit level" device (also called "bubble level"). In this video I show the complete process, from requirements and design, to prototype manufacturing of the bubble level from 2 borosilicate glass disks. If you need more details on how to make a spherical surface, you might want to check out this previous video:    • Polishing a Small Spherical Mirror Surface...   The two video's referred to below show the optical contact bonding process in detail, so make sure you check them out. It is quite impressive to see 2 surfaces melt together spontaneously by just atomic forces at the surface:    • wizard and his magic optical contacting      • Видео   The link below refers to a Sydor video on their Optipro Glassmaster 520 angular machine:    • Sydor Optics counts on multiple Glassmaste...   "Fabrication Methods for Precision Optics" by Hank H. Karow contains detailed information on how to build and operate an angular machine, for those of you interested in building one.