Porcelain is a ceramic, often referred to as China. Porcelain is a hard material, made generally from two types of feldspar--a quartz. This mixture is kiln fired and creates a nonporous glass that is extremely hard yet brittle. Different ingredients make different types of porcelain, including bone China. Porcelain plates can be transformed into clocks by drilling a hole in the porcelain plate and adding a clock mechanism. It takes patience and a hard drill bit.
Make a small mark in the centre of the porcelain plate with the marker. This will centre the clock hands on the porcelain plate. The mark is the drilling guide.
Put on safety glasses and insert a drill bit into the variable speed drill. Use a diamond-tipped drill bit for the best results. Porcelain has different degrees of hardness depending on how it was made. A diamond drill bit keeps the porcelain from chipping or breaking as easily. For some porcelain, a carbide bit may work. However, as the hardness of the porcelain may be unknown, use the diamond-tipped drill bit.
Drill slowly into the centre of the plate on the mark you made. Drilling at a slow, steady speed is important. For example, a 1/2 inch drill bit is optimal at 800 rpms for porcelain and a 1 inch drill bit is best used at 500 rpms. Don't rush drilling, and don't use pressure on the drill as the plate can break.
Spray the plate and drill bit with water for lubrication. Do this often while drilling to reduce heat and friction.
Steps 3 and 4 should be done together. During the drilling process, water should be added. A shallow tray with water can be used as an alternate water lubrication source. Or, you can form a small clay dam using modelling clay several inches around the drill and keep it filled with water as you drill. If the drill bit gets hot while using the spray method, switch to the tray or clay method.
Make sure to wear eye safety equipment. The drill bit and near the drill hole can be hot if the drill speed was too fast or not enough lubrication was used. If the drill has a power cord, make sure to keep the plug away from any water you are using for the project.