A device for support of a portable router above a work table so as to convert a portable router into a pin router assembly. The device includes a mounting plate which is directly attached to the base portion of the router. The mounting plate is formed integral with a support carriage assembly that is mounted in a housing assembly to permit the router to be smoothly and accurately positioned above the work table in preselected positions. A guide pin is carried in a block assembly that is received in the work table in a manner which permits the adjustment of the guide pin into alignment with the router chuck.