I have not used this particular drill bit but I have spent some time with others from Cobra Carbide which have not failed me. I was a little frustrated as the picture shown for this item is for the 3/8" diameter version, not the 1/4" version I ordered. I didn't pay attention to the picture as the price was great given the quality of this ridge. Buyers beware, read the actual title and description before believing the painting is what you are buying.