I use dedicated countersink bits from Bosch. I have this cheap set of combined countersink bits, but I don't recommend them because they have the same problem your set has, the bits come lose when the drill stops spinning, so I have to tighten them again before starting a new hole. A PITA.
Hi im looking to buy a table saw with a budget of £400 - £600 Not for industrial use just projects and some carpentry work. Can anyone recommend one? I'm currently thinking about getting this one below or could i get something better for my money? http://www.amazon.co.uk/gp/product/B007PB02RI?colid=TYKFUEOATWY4&coliid=I2UT06OEOMCYEI&redirect=true&ref_=s9_wish_co_d74_g60_i8