Cut flawless circles from 10" to 52" in diameter without complicated math equations! The Rockler Circle Cutting Jig sets up in minutes and mounts quickly to many popular routers made by Porter Cable, Makita, Hitachi, DeWalt, and Bosch. Or, easily drill your own holes to custom fit any router. Includes two center pivot pins which are used as a pivot point to rout perfectly arced circles (one pin is used for soft woods, use the other if your design allows drilling a center hole). A recessed groove in the jig lets you slide the center pivot pin (your center point) up or down the length of the jig to find the correct, exact diameter of your circle. Use the 4-star knob to tighten the T-bolt with the center pivot pin installed and you're ready to go!Fits the following Routers: Porter Cable 100, 690, 890, 7529, 8529 Makita 1100 Series Hitachi M12VC Dewalt DW616, DW618, DW625 Bosch 1617 Series, 1618 Series, 1619 and 1619 EVS Note: This item is not predrilled for the Bosch Plunge Base.