Abstract: The combination of a pile driving apparatus having a hammer operating mechanism mounted above a downwardly extending pile sleeve having an internal cross-section dimensioned to receive the top of a pile of a first diameter, whereby the apparatus may be guided onto and supported on the top of a pile, with an adaptor fitted within the pile sleeve and having an internal cross-section dimensioned to receive the top of a pile of smaller diameter than said first diameter, said adaptor being fabricated as a unit and the adaptor unit and pile sleeve being interconnected preventing withdrawal of the adaptor unit from the pile sleeve.