A circle cutter includes a beam with a central arbor and a pair of tool holders concurrently oppositely adjustable along the beam and having a pair of vertically spaced longitudinal bores carrying screws for engaging cutting members. An extension member engages the tool holder outer face and is detachably attached by screws engaging bores in the extension member and those in the tool holder and used for securing a tool to the extension outer face. A threaded third bore is formed in the extension below the first pair permitting the vertical adjustment of the attached tool.
