Well ,I have to say here, that I've bought a lot of "tin" drill bits and the other day I was drilling some bronze and as Boggy informed me a while ago, bronze can catch the drill bit from time to time ,I f***ed 3 of my ,apparently good bits trying to get through and in the end I got through with some Dormer bits that I bought from a local supplier, because I needed some in between (.1,.3 etc) sizes,they weren't so expensive ($3 apiece for 6.3mm) obviously the bigger they are the more they cost but if you buy one every now and again it won't break the bank, and you'll have indestructible drill bits that'll last a long time, they are so well made that you almost get a reamed hole!. IMO use the cheap bits to go near size but get good ones to finish the hole, otherwise it's false economy... in a sense you still get what you pay for, buy 5 cheap ones for the price of 1 good one?..plus it's not so easy to sharpen say a 6.2mm drill bit so that it will still make a 6.2mm hole unless you have some serious sharpening gear...anyway, thats my 10 cents worth!.....Giles