I do not think it is possible to use the press on adapters with the steel shank bits from the set. My 90 from the set (as well as other 1/4" shanks from the set) measure a little small and the press on adapters would not be tight enough. In fact, I can get the adapters on by hand without any heat or force. Carbide bits have very precise shank diameters whereas steel shanks seem to vary more. I have other steel shank router bits which would work. One would have to be careful. No go with my CW set.