Abstract: An apparatus for drilling a circularly curved hole in a workpiece, following a curved path around an arc includes a support, shaped to rest against the workpiece, a chassis mounted to the support on a pivot axis defining a center of the curved path, and a drilling bit. The drilling bit is disposed on the distal end of a shaft which is likewise curved around the path, and is provided with a power transmission section connected to the drilling bit and disposed along the arc, coaxial with the pivot axis of the chassis. An electric motor or electric hand drill with chuck is used to apply power to the power transmission section, while manually forcing the chassis around the pivot axis, thereby moving the drilling bit along the path. The support can be adjustable to span and/or clamp on the workpiece. The power transmission section can include an internal or external member carrying power along a fixed tube or shaft respectively.