A power tool for forming a channel in a work surface includes a first section carrying a rotatable shaft having a shaft axis and a second section that engages the work surface; a cutting disc having a substantially circular blade provided on the rotatable shaft; a first support portion on one side of the cutting disc and a second support portion on the opposite side of the cutting disc which cooperate to hold the cutting disc at an oblique angle relative to the shaft axis. A first locking feature of the first support portion and a second locking feature of the second support portion extend through a circular opening of the cutting disc and cooperate to resist relative rotation of the first and second support portions. The first section is movable relative to the second section to move the cutting disc into and out of engagement with the work surface.

A portable machining apparatus facilitates addition of new electric components with an intended arrangement of various electric components. The portable machining apparatus includes a housing, an electric motor installed in the housing and including a motor shaft extending in an axial direction, a tip tool partially or fully exposed outside the housing and rotatable by the electric motor, a controller installed in the housing and aligned with the electric motor in the axial direction to control an operation of the electric motor, and a first electric component and a second electric component installed in an electric component compartment between the controller and the electric motor. The first electric component and the second electric component are aligned in a same plane perpendicular to an axis of the motor shaft.