Abstract: A digger for digging out substantially vertically-sided holes e.g. for gravestone monument foundations, is in the form of an attachment adapted to be connected on the dipper stick of a backhoe machine. The attachment has a downwardly-depending digger frame pivoted at its upper end to an attachment frame which is connected to the free end of the dipper stick. A vertically extending operating shaft extends upwardly relative to the digger frame and is connected through a pair of lower linkages to the sections of a clam shell bucket mounted on the lower end of the digger frame. The upper end of the operating shaft connects through a connecting link and a rocking lever to the piston of the dipper stick piston and cylinder arrangement.