I bought this set to replace old bits I had and have been using for over 10 years and put them in my tool kit for several months. return. I used the largest bit 2 days ago to drill 6 holes just to get the hex shaft turning on the shank. Upon closer inspection I found that the pin attaching it to the shaft had been sheared off rendering the bit unusable. Needless to say I am very disappointed with the product.