I couldn't find a thread on this. I mean actors who worked together on a movie and detested each other, not stuff going on in their private lives. The most famous was the war between Joan Crawford and Betty Davis during the filming of Whatever Happened to Baby Jane. They were suppose to repeat in Hush, Hush, Sweet Charloette, but Crawford decided to bail out.
There are conflicting reports about Lugosi and Karloff. I have the impression they got along reasonably well, although Lugosi may have privately resented Karloff and wasn't happy he had to participate in Karloff's tea breaks. Not so with Lugosi and Chaney Jr. Lugosi didn't like Chaney calling him, "Pop," and a possibly drunken Chaney almost slugged Lugosi during the filming of "Black Sheep."