Thank you Robertmet and EdStainless for your answers to my inquiry. I have asked because I was looking for a cannulated drill bit (3.20 mm x 1.70 mm) and a particular supplier informed me that their drill bits are made out of grade 202 stainless steel. We normally use 17-4 PH and 304 grade and our passivation process employs more than 40% nitric acid solution. Again, Thank you.