If i remember well,you can remove the stud from the case by hitting it,they are not screwed in the case.It will fall in the empty oil tank,use a small magnet to get it out.The are pressed in the case,not hard to remove usually.You can check studs from Husky or Jonsered,the should be the same size but with a different "head" shape.You can modify the head to bring it like the Partner.