
A machining center comprises a bed and an arch-shaped column having a pair of post portions spaced from each other in the transverse direction of the bed and a crossbeam portion connecting the post portions. A spindle head is supported on the crossbeam portion of the column to be movable both in the vertical direction and in the transverse direction of the bed and supports a spindle which is rotatable about a substantially vertical rotating shaft and on which a tool is demountably mounted. A bas...











