As of yet, I've only come across two spellings in this family. My step-father is spelled...Dansak. His father supposedly changed the spelling from Dancsak. These are the names I'm currently researching...
Paul Dancsak and Mary Sikur had Arthur, Rudolph and Joseph Dancsak. I'm sure I should be able to find someone somewhere that spells it Danchak, because that's the way I'm told it is pronounced.