Hi All, After TIN coated tools came onto the market the next generation available seems to be cheap Colbalt Steel Drills. I bought a set but keep them for special jobs like when I broke a bolt off in the cylinder head of my car and I used one to make a hole down it, so that I could use a stud extractor.It went in like drilling cheese. Regards Clif MODEL ENGINEERING DISCUSSION LIST. To UNSUBSCRIBE from this list, send a blank email to, modeleng-request@xxxxxxxxxxxxx with the word "unsubscribe" in the subject line.