I've drilled about 50 holes in ceramic pots of various thicknesses and these drill bits did the job! Some of the pots were quite thick and I didn't think the pieces would pull through. I didn't actually use the smallest two so all 50 holes were drilled between the three big ones. They're starting to get a little boring, but still work. I highly recommend using water when drilling. I bought a drill bit from the hardware store for about $15 and for the same price I could get anything. Very happy with this purchase.