Rhino Impact Diamond Drill Bit 25mm/ 1"

I used this product to drill numerous holes in porcelain tiles and it still has lots of life left in it. However, I also applied water frequently with a small squeeze bulb from an ear wax removal kit, while using the bit and I kept the speed at a slow but sure pace to minimize heat build up. I also used clamps where possible to hold thick transparent plastic with appropriately sized holes that I pre-drilled to keep the bit properly and accurately positioned in my hand drill. I saved a lot of money, without sacrificing results.

I needed to alter a hole in a glass sheet. Worked great... Keep it in water and you will have no problems... I use plumbers putty and make a circular damn around the area to drill ... fill with water and drill away.